helix delta t-5_help

Introduction to Helix delta-T

Welcome to the Helix delta-T Conveyor Design Program - an essential tool for engineers, contractors and plant operators to quickly and easily optimise Conveyor system designs.

Automatic Selection of Belt and Tension, Power Calculations

Equipment Selection from Databases for Belts, Idlers, Pulleys & Shafts, Gearboxes, Motors, Fluid Couplings, Brakes etc.

Create a 3D model of the conveyor

Calculate Vertical Curve radii and super-elevation (banking) angles for Horizontal curves

Add any number of Conveyor Pulleys, Drives, Loading points, Trippers, Brakes etc.

Over 60 reports can be viewed, printed or exported to Word, PDF files or Excel etc.

Helix delta-T has been used as the design tool and proven in many hundreds of real conveyor installations in more than 25 countries around the world for than 10 years. The latest version Helix delta-T 5 brings you even more power and flexibility in your conveyor designs.

New Dynamic Analysis version available - November 2003

A new version of the program which has full Dynamic Analysis capabilities has been added to the existing Lite, Standard and Professional versions of the software.

This new version calculates the transient belt Tensions and Velocities during starting and stopping of a conveyor. It can model the conveyor belt transient behaviour during Starting Fully Loaded, Starting Empty, Stopping Fully Loaded and Stopping Empty. The program allows the user to input any number of Drives or Brakes and allows for input of Drive Torque / Speed curves, Delay times, Braking Torques, Flywheels and inertia effects. After the Dynamic Calculations have been performed, the user can view and Print two dimensional and surface plot three dimensional graphs for Belt Tensions, Belt Velocities, Strain rates and Takeup movement versus time step for all points along the conveyor.

The Dynamic calculation process uses sophisticated Variable Step Runge Kutta method integrators for solving the complex differential equations, including flexible, easy to use boundary condition specification by the user.

The Dynamic Calculations are easy use to use and Engineers who have static conveyor design experience can perform these complex dynamic simulations using this very powerful software.

The program will automatically calculate the belt tensions in the system, select a suitable belt from the database, calculate the pulley and shaft sizes required, select a suitable electric motor, fluid coupling and gearbox from the databases, calculate the idler shaft deflections and bearing life and then present the full conveyor design in reports which can be viewed, printed or exported to Word for Windows, Excel, PDF files and other applications.

Belt tensions can be viewed graphically, and the Calc section provides useful procedures for calculating discharge trajectories, vertical curve radii and other frequently performed routines. Context sensitive on screen Help will guide you through the operating procedures and provide the formulae used in the calculations.

You can also create and view a 3D model of the conveyor and merge in a digital terrain model. The program also allows you to dynamically calculate vertical and Horizontal curve geometry for the conveyor.

In addition, delta-T provides an in-depth analysis of conveyor belt tensions under different operating conditions such as running fully loaded, running empty, starting fully loaded, starting empty, braking fully loaded, braking empty and coasting. A new sketch facility allows users to sketch the conveyor profile and enter data in tabular format.

delta-T will save you time and reduce your plant capital, maintenance and operating costs.

New Features in delta-T version 5

The new Professional version includes the following features:

• Powerful OpenGL 3D modeling of the conveyor and terrain

• Completely New design report formats - over 50 reports can be generated easily, with excellent presentation of the design.

• Belt Tension calculations for Running, Starting and Braking including accelerating and stopping times.

• Calculation to ISO and CEMA standards with auto friction factor calculation.

• Bar and 3 D line graphs of belt tensions under different loading and starting and braking conditions.

• Improved Braking calculations including a Brake database and Brake Selection routines.

• Improved equipment database for Belts, Idlers, Motors, Gearboxes, Fluid Couplings, Brakes etc. Copy and Paste data from Excel.

• New Database system compiled directly into the program - this eliminates previous issues with the MS MDB files system.

• Ability to import or copy and paste data directly from Excel spreadsheets to conveyor design or equipment databases.

• New Sketching facility to quickly add pulleys, hoppers and drives to your conveyor

• New scale drawing system for live feedback on Vertical curve radii - just drag an intersection point on the screen and the vertical curve is redrawn in front of you so that you can see immediately if you can fit the radius into the geometry.

• New Horizontal Curve Calculation routines - belt drift and banking angle calculations, with live on-screen feedback about radii.

• Completely New design report formats - over 50 reports can be generated easily, with excellent presentation of the design.

• Export design reports directly to MS Word® Excel® or PDF® file formats plus others.

• Improved Belt Selection routines with diagrammatic feedback on belt width vs. load area and edge distance.

• Estimating and Costing schedules for all conveyor equipment from civil & electrical to conveyor components.

• New comprehensive instruction and context sensitive help files

• New Belt Feeder / Hopper pullout calculations.

• Software Operation & Technical conveyor Design support.

Dynamic Analysis Calculation Features

• Easily model the belt transient tensions and velocities during Starting and Stopping of conveyors.

• Add Torque Control or Speed Control on drive acceleration.

• Add Delay times for multiple drives for Dynamic Tuning

• Add Flywheels to pulleys to optimize starting and stopping

• Add Brakes to pulleys as required.

• View the movement of the Takeup pulley during Starting and Stopping

• Predict the maximum Transient Belt Tensions at any point along the conveyor as well as the timing of these transients.

• Compare the Dynamic Calculations results with the rigid body static calculations in the delta-T5.

• Predict the magnitude of transient loads on conveyor structures.

• Calculate the torque loadings on gearboxes and couplings during starting and stopping. Eliminate conditions which may cause costly equipment failures.

• Perform Dynamic Tuning by changing the start delay times on different drives

References

The following references were used during the development of this program :

BELT CONVEYORS FOR BULK MATERIALS, Conveyor Equipment Manufacturers Association (CEMA), 2nd onwards

HAND BOOK OF CONVEYOR AND ELEVATOR BELTING, Goodyear Tire and Rubber Company

CONVEYOR BELT DESIGN MANUAL, Bridgestone

CONVEYOR BELT DESIGN MANUAL, Dunlop Industrial Products

CONVEYOR BELT SYSTEM DESIGN, Continental

CONTINUOUS MECHANICAL HANDLING SYSTEMS - BELT CONVEYORS WITH CARRYING IDLERS ISO 5048, International Standards Organisation

BELT CONVEYORS FOR BULK MATERIALS, Deutsche Norm, DIN 22101

THE MELCO PRECISMECA BELT CONVEYOR IDLER ROLL, Melco Mining Supplies (Pty) Ltd

CONVEYOR IDLERS - MATHEMATICAL SELECTION CRITERIA, Adi Fritella

Criteria for Minimising Transient Stress in Conveyor Belts

A. Harrison Mech Eng Transactions 1983

On the Appropriate Use of dynamic Stress Models for Conveyor Design

A. Harrison Bulk Solids Handling Vol 8, No 6 December 1988

Future Design of Belt Conveyors using Dynamic Analysis

A. Harrison Bulk Solids Handling Vol 7, No 3 June 1987

On the application of beam elements in Finite Element Analysis of Belt Conveyors Part 1

G. Lodewijks, Netherlands

Bulk Solids Handling Vol 14, No 4 October 1994

Analysis of Belt dynamics in Horizontal Curves of Long Belt Conveyors

G. Schulz, Germany

Bulk Solids Handling Vol 15, No 1 Jan/March 1995

Transient Belt Stresses During Starting and Stopping: elastic

L.K. Nordell, Z.P. Ciozda, USA

Bulk Solids Handling Vol 4, No 1 March 1984

Response simulated by FEM

Technical Requirements for Operating Conveyor Belts at High Speed

A. Harrison and A.W. Roberts

Bulk Solids Handling Vol 4, No 1 March 1984

Flexural Behaviour of Tensioned Conveyor Belts

A. Harrison The Institute of Engineers, Australia

Experimental Investigations and Theory for the Design of a Long-Distance Belt Conveyor System

H. Funke & F.K. Konneker, Germany

Bulk Solids Handling Vol 8, No 5 October 1988

Stress Front Velocity in Elastomeric Belts with Bonded Steel Cable reinforcement

A. Harrison Bulk Solids Handling Vol 6, No 1 February 1986

Analysis of a Long Belt Conveyor using the Multi-body Dynamics Program

Hyung-Suk Han et al, Korea

Bulk Solids Handling Vol 16, No 4 Oct/Dec 1996

Uphill and Downhill Conveying of Important Mass Flows

G. Schulz, Germany

Bulk Solids Handling Vol 15, No 4 Oct/Dec 1995

Feedback Control of Conveyor systems

L.F. Wee and G. Ledwich, Australia


Non-Linear Dynamics of Belt Conveyor systems

G. Lodewijks, Netherlands


Dynamic Behaviour of steel cord conveyor belts

A. Harrison Colliery Guardian vol 221 sept 1981 pg 459

Transient Stresses in long conveyor belts

A. Harrison

Further Results in the Analysis of Dynamic Characteristics of Belt Conveyors

Schulz G Bulk Solids Handling, Vol.13, No. 4, p. 705-710. November 1993.

Schulz G.: Calculation of the Dynamics of Long Belt Conveyors

Viscoelastic Properties of conveyor belts modeling of vibration phenomena in belt conveyors during starting and stopping

Zur, T.W Bulk Solids Handling, Vol.6, No. 3, p. 705-710. November 1986.

Getting Started with delta-T

To start using Helix delta-T 5 follow these steps :

Start the program and select the File, New File menu or press the New button.

Press F1 for Help at any point in the program or use the Help Contents or Search menus.

Type in a new file name - for example - My new File and press Open. A new set of design files will be created. This set of files will all be preceded by the file name you entered e.g. My New File. A list of files and their contents can be viewed under the Design Files. Help topic. When you crate a new file the contents of the Master design file are copied into the new files.

Now create the conveyor sketch profile. Press the Conveyor Profile Schematic Diagram tab sheet and the current conveyor profile sketch will be displayed. This may look something like the one shown below:

Click the Delete Items button to delete pulleys, hoppers etc that you do not want in the conveyor. Use the Add Pulleys, Drives, Intersection Point, Hopper and Take-up buttons to add items at the end of the list. Refer to the Adding Pulleys, Drives Hoppers input form for details on how to build the conveyor model.

Move, select Items

Delete Items

Add Pulley

Add Drive

Add Intersection Point

Add Hopper

Add Take-up Pulley

Insert Item

The program automatically starts at the Tail pulley and works in a clockwise direction around the conveyor towards the Head on the Right hand side and then returns back to the tail pulley.

Once you have drawn the conveyor profile sketch, input the Conveyor Capacity, Idler Spacing etc on the Conveyor Sections input tables.

Now select each of the Duty Input menu options and input the data for the following input Forms :

Input Project Details.

Input Conveyed Material

Input Conveyor Pulleys and Sections You may already have done this above.

Input Take-up Details

Input Carry Idlers

Input Return Idlers

Input Drive Details

Input Motor Details

Input Gearbox Details

Input Fluid Coupling / Soft-starter Details

Input Brake Details

Input Pulley Shaft Details

You can now perform a Conveyor Design Calculation using the ISO or CEMA calculation buttons.

The Design Reports can now be Viewed and Printed or Exported using the Reports menu or the Report buttons on the toolbar.

Check that the Take-up Tension is sufficient by viewing the Take-up and Drive Traction report and the Tension Summary Report. If not, increase the Take-up mass manually and re-calculate.

Review all Design Reports and refine your design.

Note any warning messages during the design calculation and modify your input data accordingly.

The program automatically saves your data in the design file as you go along. If you want to investigate different design options, use the Save as… menu to create a new file before making your changes.

You can now build a Cost Estimate and also create Equipment Schedules.

Create a 3D model of the conveyor and view Terrain data.

Calculate Vertical Curve radii and super-elevation (banking) angles for Horizontal curves

Add any number of Conveyor Pulleys, Drives, Loading points, Trippers, Brakes etc.

Over 60 reports can be viewed, printed or exported to Word, PDF files or Excel etc.

Helix delta-T has been used as the design tool and proven in many hundreds of real conveyor installations in more than 25 countries around the world for more than 10 years. The latest version Helix delta-T 5 brings you even more power and flexibility in your conveyor designs.

The program will automatically calculate the belt tensions in the system, select a suitable belt from the database, calculate the pulley and shaft sizes required, select a suitable electric motor, fluid coupling and gearbox from the databases, calculate the idler shaft deflections and bearing life and then present the full conveyor design in reports which can be viewed, printed or exported to Word for Windows, Excel, PDF files and other applications.

Belt tensions can be viewed graphically, and the Calc section provides useful procedures for calculating discharge trajectories, Belt Feeder and Hopper pullout forces, vertical curve radii and other frequently performed routines. Context sensitive on screen Help will guide you through the operating procedures and provide the formulae used in the calculations.

You can also create and view a 3D model of the conveyor and merge in a digital terrain model. The program also allows you to dynamically calculate vertical and horizontal curve geometry for the conveyor.

In addition, delta-T provides an in-depth analysis of conveyor belt tensions under different operating conditions such as running fully loaded, running empty, starting fully loaded, starting empty, braking fully loaded, braking empty and coasting. A new sketch facility allows users to sketch the conveyor profile and enter data in tabular format.

delta-T will save you time and reduce your plant capital, maintenance and operating costs.

Conveyor Design Files

Each conveyor design consists of many files, all linked together by a common file name. When you open a New Conveyor Design File the program copies the Master files as a template for the new project. This program uses the popular DBISAM database engine for storage of all data.

Every time you start the program, it automatically opens the Master.DES Conveyor Design file. You can then use the File, Open menu to open an existing file, or create a New Design file before proceeding to do your design.

Conveyor Design FilesThe Master File set consists of the following file names which make up a conveyor Design:

File Name Contents

New FileCreated

Remarks

Master.DES Header file only Yes File name is used as prefix for all other Conveyor Design files

Master.DAT Conveyor Input and Output Data

Yes The main data storage file for a conveyor Design

MasterCostCategory.DAT Cost Estimate Category Table Yes Estimating Form Contents

MasterCostTab.DAT Cost Estimate Items Table Yes Estimating Form Contents

MasterDrive.DAT Conveyor Drives Table Yes All conveyor Drive Data

MasterPull.DAT Conveyor Pulley Table Yes All conveyor Pulley Data

MasterSect.DAT Conveyor Sections Table Yes All conveyor Sections Data

MasterTerrain.DAT Conveyor Terrain Data Table Yes Terrain Data X,Y,Z co-ordinates

MasterDynDrives.DAT Drive Starting Torque data for the Dynamic Analysis Program

Yes Only required by the Dynamic analysis version

MasterDynInput.DAT Dynamic Analysis Design input data

Yes Used by Dynamic Analysis version only

Note: Each of the above files has an Index file, denoted by .IDX file extension, as well as a .DBK file which is a backup of the .DAT data file, and a .IBK file which is a backup copy of the Index file.

When you create a new project, the Master files listed above are copied, the tables emptied, and the new file name is appended as a prefix in place of the word Master.

For example, if you create a new project called My New Conveyor, new files called My New

Conveyor.DES, My New Conveyor.DAT, My New ConveyorCost Category.DAT etc. will be created.

Only files with a Yes in the New File Created column above are created.

The Conveyor Design files are actually live DBISAM database files, which means the data is Automatically saved as you go along.

If you want to make changes to a file, but keep the original data intact, you must create a New conveyor design file using the File, Save as.. menu option. This will create a duplicate file with the new name and if you need to revert to the old file, use the File, Open menu to open the original file.

Database Files

In Addition to the conveyor Design Files, there is a set of Equipment Database files. The files are located in the Data subdirectory of the main program.

File Name Contents Remarks

Belts.DAT Conveyor Belting Data Table Add you own data if required

BeltWidths.DAT Conveyor Belt Widths Data Ditto

BrakeTable.DAT Conveyor Brake Data Ditto

Covers.DAT Conveyor Belt Covers Data Ditto

FLCplgs.DAT Fluid Coupling Data Ditto

Gboxes.DAT Conveyor Gearbox Data Ditto

Idlers.DAT Conveyor Idler Data Ditto

Materials.DAT Conveyed Materials Data Ditto

Motors.DAT Motor Data Ditto

Pulleys.DAT Pulley Data Ditto

PulleyShafts.DAT Pulley Shaft Data Ditto

PulleyWidths.DAT Pulley Face Width Data Ditto

ReportList.DAT List of Reports to Print Internal use only

UnitsEnglish.DAT Units Internal use only

UnitsMetric.DAT Units Internal use only

These files are not project or design specific. They can be accessed to capture data into the current

design file, or to do equipment selections during the design calculation process.

Backing- up Data

It is recommended that regular back-up's are made of all data files. The files are installed in the c:\program files\Helix\delta-T5\Data sub-directory. Exit the program before making the back-ups.

Copying a Project to send to another PC

You can copy all the files listed in the table above and move them to a new PC or send by email to someone else who has the Helix delta-T5 program to use.

Freezing or Preserving a Design file

You should set all the Equipment selection options to Manual on the Duty/Input forms if you want to preserve your equipment selections. If any switches are left on Auto, when the file is run again, the program will try to select equipment from the current database files, and if the data files are different, different equipment will be selected.

A further method of tracking revisions, and one which we recommend, is to implement a conveyor design file naming system which contains the revision number. For instance, you could name a design file

‘ABC Mining Project Conveyor CV102 Rev A.des’

When the next revision is issued, the file is saved as (name is changed and saved before modification)

‘ABC Mining Project Conveyor CV102 Rev B.des’

and the original file is preserved, using the ‘Freeze’ method mentioned above.

Click the Duty/Input, Project Details main menu. Press the Freeze / Protect Design File form button. The following form will be displayed.

You can set individual items to Manual or use the Freeze All / Un-Freeze All buttons.

Data Recovery

If your data becomes corrupted, you can make copies of the files and then try to restore the original file by renaming the .DBK file to a .DAT extension, and the .IBK file to a .IDX file extension.

Exit the Helix delta-T program

Copy all files in the \Data sub-directory to a temporary backup directory

Rename .DBK files to .DAT files

Rename .IBK files to .IDX files

Try running the delta-T program again and opening the project file.

If this doesn't work, contact Helix for a utility to recover your data.

Repair Database Utility - DBSYS.EXE

If a data or design file becomes corrupted, you can try to repair the file using the Database Utility program supplied with Helix delta-T. This program is called DBSys.exe and is located on the Helix CD ROM and in the main program file directory. Copy it to your hard disk and then run it and select the Utilities, Repair Database menu option. Then select all the DAT files in the Data (or Project )

directory. The DBSys program will repair the files. Once the DAT files have been repaired a log file will be displayed showing what if any errors were found

Open / Create a New Design File

You should create a New Conveyor Design file for each design.

Select the File, New menu and type in a new file name and press the Open button.

The default file extension is .DES, denoting a Conveyor Design File.

This DES file links together all the various sub-files which make up a Conveyor Design.

For example, if you type in a file name 'MyFile.DES', the program will copy the contents of the Master Design files into a New set of design files preceded by the word MyFile

Refer to Conveyor Design Files for a list of files and the data contained in them.

Setting Up your Project Details

Once you have opened a New Conveyor Design file, you can set up the Project details.

Select the Duty / Input, Project details menu and the following form will be displayed.

Record your current project details in this form. You can add notes and comments about the conveyor design in the Designers Comments text window at the bottom of the form.

The ISO or CEMA calculation method displays the last calculation method used. This calculation method will be set automatically when you press the ISO or CEMA buttons on the main form to perform a design calculation.

The Temperature window is to record the Minimum expected site temperature. When you edit this temperature, the temperature correction factor Kt is automatically calculated and will be applied to the design power requirements. Refer to the Temperature Correction help topic for more details. The Kt value will be printed on the Design Summary report form.

The Metric units check box is for future use.

Drawing the Conveyor Profile

Introduction and Overview

The heart of the delta-T program is the Conveyor Profile sketch. This sketch, along with the Pulley and Section Tables, form the basis of the conveyor design.

The Pulley table is a list of Pulleys, Loading Hoppers, Drive Pulleys, Intersection Points and the Take-up of the conveyor.

The Sections table is a list of the conveyor sections between the items or pulleys listed in the Pulley table and contains information such as the Idler spacing, the capacity loaded on the section, skirt and scraper details and so on.

By definition, every item in the pulley table must have a corresponding Section in the sections table. The total number of pulley items must equal the total number of sections.

The Drives table is the third link to the conveyor Profile sketch. Every Drive pulley must have a corresponding Drive in the Drives Table. The Link to Drive No column in the Pulley Table tells the program which drive in the Drives table to link to each drive pulley.

Every Drive Pulley MUST be linked to a Drive in the drives table by typing in the Drive number in the Pulley table.

Important rules for creating a conveyor

The number of Pulleys must equal the number of sections.

Every conveyor must have at least one Drive and one Take-up pulley (and of course two Sections - one Carry, one Return).

Each Drive in the Pulley Table must be linked to a Drive number in the Drives Table.

Start at the Tail pulley of the conveyor. Place this pulley on the left of the screen. Add pulleys in a clockwise direction (following the belt travel direction) towards the Head or discharge pulley at the right hand side and then add the return side items back towards the Tail pulley. The program will automatically link the last item back to the first item.

0 Refer to the Adding Pulleys, Drives, Hoppers and Takeup's help topic for details.

Adding Pulleys, Hoppers, Drives & Take-up

Introduction and OverviewStart the program and select the File, New File menu or press the New button.

Type in a new file name - for example - My new File and press Open. A new set of design files will be created. This set of files will all be preceded by the file name you entered e.g. My New File. A list of files and their contents can be viewed under the Design Files. Help topic. When you crate a new file the contents of the Master design file are copied into the new files.

Press the Conveyor Profile Schematic Diagram tab sheet and the current conveyor profile sketch will be displayed. This may look something like the one shown below:

Your conveyor will probably have a completely different layout - you can delete the existing pulleys and then add your own pulleys.

The Following Tool Buttons are provided on this form

Move, select Items

Delete Items

Add Pulley

Add Drive

Add Intersection Point

Add Hopper

Add Take-up Pulley

Insert Item

The easiest way to draw your Conveyor is to delete all items from the list and then add your own items in the order required.

Press the Delete Items button and move your mouse over any of the Pulleys - you will notice that the cursor changes to a "Delete" item view. Click on the last intersection point or pulley on the sketch - this will be the one just before the belt returns to the tail pulley.

Delete all of the pulleys, intersection points etc until only the first two items remain. Do not delete the Tail pulley and the Hopper. Each conveyor must have at least two items (Take-up and Drive), but we will add these later. When deleting a Drive, you will be asked whether to delete the drive

linked to this Pulley - Press Yes.

You should now have something like this on the screen:

Note that there are only two items in Pulley table.

Click on the Sections tab next to the Pulley Data tab sheet. You will note that only two Sections remain in the list. This is because delta-T tries to maintain the same number of sections as pulleys at all times.

You can now add your own pulleys. Click on the Add Intersection Point button. A new Intersection point will be added to the sketch at the top left hand side. Now drag the new intersection point down and to the right of the loading hopper using the Left mouse button. When you release it, the new conveyor line is drawn back to the tail, and the new Int. Pt is added into the table.

Press the Add Drive button. A new drive will be added on the top left of the screen. The Link to Drive No cell will automatically be entered as 1. It is the users responsibility to Ensure that each Drive Pulley is linked to the Correct Drive number in the Drive table.

2 Drag the new drive to right and above the previously added Int. Pt. The belt line will be re-drawn. Right click on the Drive Pulley. The Input Drives form will be displayed.

This form can also be accessed from the Duty/ Input, Drive Details main menu. You can input the type of Lagging, Wrap angle Load Share % and other inputs. Click on the Drive Table tab sheet. A Table with the Drive details will be displayed. Refer to the Input Drives Help Topic.

Click on the Drive Table tab sheet. A Table with the Drive details will be displayed.

This table contains all the drive parameters for all drives. Close this form and return to the Sketch

Press the Add New Pulley button

Drag the new pulley to below the Drive pulley. This will be a snub Pulley

Note the Belt is not drawn correctly on the snub pulley as it contacts the top of the pulley and leaves it at the bottom. We need to adjust the Belt Contact and Departure Angles on the pulley to correct this.

Click in the Pulley Data, Pulley Co-ordinates table row number 5 (the pulley we have just added). Move to the Ptype column and click once on the Word Pulley. A Drop down arrow will appear. Click on this drop down arrow and a list of Pulley Types will be displayed. Select Snub from the list by clicking on it. The Ptype will now Display Snub.

Now move to the right in the Pulley table until the Contact Angle and Departure Angle columns are visible. These cells control where the belt line contacts and departs from the pulley using the following co-ordinate system and angles.

The contact angle in the above sample is 295 degrees, the departure angle is 80 degrees and the direction of Rotation is Clockwise.

Returning to our Snub pulley key in a contact Angle of (say) 70 degrees and Departure Angle of 90 degrees, and in the clockwise Column, click on the Drop Down Arrow and Choose False to set Rotation Direction to Anti-clockwise (True = Clockwise, False = Anti-clockwise). The Rotation direction determines the angle of Wrap on the pulley.

Move the Snub pulley in close to the drive pulley in the sketch. The Belt Line will now be re-drawn at the correct Contact and Departure Angles.

We have now got a basic conveyor, except for one important thing - there is no Take-up pulley in the system. Click on the Tail pulley in the sketch to give it the focus. Now, in the Pulley data, Pulley Co-ordinates table, find the PType column and in the Drop Down box select the Take-up from the list by clicking on it. This will change the Tail pulley to a Take-up pulley. We now have a basic conveyor, but we need to add more details.

We have now entered the basic profile but we still need to enter the actual co-ordinates of each pulley in the system. These co-ordinates indicate the relative positions of each pulley or

intersection point in space, using a 3 dimensional co-ordinate system, with the Z-axis being the vertical axis.

In the Pulley Data, Pulley Co-ordinates table, select the take-up pulley row and move the X column. This is the X co-ordinate of the centre of this pulley. Key in a 0. In the Y co-ordinate, key in a zero and also for the Z co-ordinate. X=0, Y=0 Z=0

Now enter an X, Y, and Z co-ordinate for the Hopper of 2, 0, 0.4 respectively. This means the Hopper is 2m away from the centre of the tail pulley. You have raised the hopper to the Belt line by increasing the z co-ordinate to 0.4 (half the pulley diameter, say 0.4m).

Continue to enter the X, Y Z co-ordinates of each item in the sketch. In the example we have the Drive pulley 15m away from the Tail / take-up pulley.

We now need to enter the details of the conveyor Sections - Load on each section, the idler spacing, skirts etc. click on the Sections tab sheet to see the data required.

Refer to next Topic, Conveyor Sections to continue.

Insert a Pulley or Hopper etc.To insert a pulley or item in the sketch follow the instructions in the Insert Pulley, Drive, Hopper or Int. Pt help topic.

Insert Pulleys, Hoppers, Drives etc.

Inserting a Pulley or other item in the Profile Sketch

0 You can add items into the pulley sketch using the buttons for Pulley, Int. Pt, Drive etc on the toolbar.

1 Add at end of list.

2 These buttons add the new item at the end of the list of pulleys and the belt line is drawn from the first item to the last in a clockwise direction.

3 If you want to insert an item into the sketch at an intermediate position in the list, move the mouse to the position of the pulley where you want to insert and then Right Click and press the Insert Pulley popup menu. A copy of the pulley or item will be inserted.

4 Alternatively, follow these steps:

Click on the Pulley Data, Pulley Co-ordinates tabsheet.

Scroll to the position of the Pulley, Drive, Int. Pt or Hopper located just before the position you want to insert an item at.

Click on this item in the Pulley Co-ordinates Grid to give it the focus. This row will be copied.

Move the mouse up to the Insert button on the left of the sketch and click. Do not move the mouse over the sketch, as this will change the position of the cursor in the pulley grid.

The new item will be inserted as a copy of the current Row selected in the Pulley Grid.

Change the inserted Row PType to suit the type of item required i.e if you inserted an Int. Pt you can change it to a Pulley, Hopper etc.

Conveyor Sections

The Conveyor Sections table allows you to input details about the conveyor between Pulleys, Intersection Points, Loading hoppers / points etc. This data includes the Capacity in Tonnes per hour loaded on the sections, the Idler Spacing, the Friction Factor, Skirt Lengths and also the number of Scrapers on the section. Click on the Sections tab sheet and select the Input Section Lengths, Lifts, Capacities … tab sheet.

The sections must numbered consecutively from 1 upwards. The Section Type column allows you to select whether the section is a Carry or Return Section. In the example above, we would need to set sections 4 and 5 to return sections by clicking on the Drop Down Arrow and selecting Return from the list.

The Length of section and the Lift of each section are calculated from the X, Y, and Z co-ordinates entered in the Pulley Data tables.

The Capacity column is where you enter the loaded capacity of the section. A loaded section is drawn with a thicker black line than an unloaded section in the sketch. Enter a Capacity of 777

tph over sections 2 and 3 in our example.

Alter the Carry Idler spacing to 1.2 m (say) for the carry sections and 3m for the return sections. You can lookup Recommended Idler Spacing.

The f Factor input column is the Friction Factor to apply over this section during the Tension Calculations. If this column is left as a 0 (zero) the program will automatically calculate a Friction factor which will appear in the f Factor Calculated column. Using the CEMA calculation button will result in a friction factor obtained from the CEMA Ky tables, and if the ISO calculation button is used, a Friction factor will be interpolated from the following table, based on the belt sag and the idler trough angle for the conveyor section:

The following table is used by the ISO calculation method to determine the friction factor values:

Loaded Belt Empty BeltCarry Side Average

Belt Sag %35 degree Idlers

fx45 degree Idlers

fxAll Idlers

fy

2.00 to 3.00 % 0.030 0.035 0.0151.00 to 2.00 % 0.024 0.032 0.0150.75 to 1.00 % 0.023 0.029 0.015

0.50 to 0.75 % 0.022 0.027 0.0150.40 to 0.50 % 0.021 0.025 0.0150.30 to 0.40 % 0.020 0.024 0.0150.20 to 0.30 % 0.019 0.022 0.0150.15 to 0.20 % 0.018 0.020 0.015

< 0.15 % 0.016 0.018 0.015

Intermediate values are calculated by interpolation, and repetitive iterations of the calculation algorithm are performed in order to arrive at the final f Factor vs Sag values.

The average belt sag is displayed on the Belt Tension Summary Report.

Details of the friction factors used can be obtained from the Loading Tensions reports.

Temperature Correction

Where the minimum site Temperature falls below zero degrees Celsius, an increased Friction factor Kt may be applied according to the CEMA method.

This Kt factor is detailed in the Temperature Correction Factor help topic.

Declined conveyor sections - reduced Friction

For decline sections of the conveyor, where the slope exceeds 2.5%, a reduced friction factor will be used if the CEMA method of calculation is used. This reduced friction is 0.66 times the normal friction and it is intended to increase the power that would be required to restrain a declined belt. The concept is explained in the CEMA manual, but it is essentially a safety factor to ensure that Friction on declined sections is not overestimated resulting in a motor power which would be insufficient to stop the belt from running away.

Warning: A conveyor with inclined and declined sections should be examined very closely by the user in order to avoid under-sizing the motors because a reduced friction factor has been used on the declined sections. As a general rule, the designer should investigate the power required under full friction and using a reduced friction factor, and then choose a large enough drive to overcome the worst case.

No reduced friction factors are applied when the ISO calculation method is used, and the user should adjust the Friction factors downwards if the conveyor is re-generative.

To view the Friction factors used refer to the Design, Loading Tensions menu reports. The Friction factor used for each conveyor section is shown in the last column of the Loading Tension reports.

SkirtsEnter the total linear length of the Loading Skirt in m. The program will calculate the additional tension due to friction between the skirt and the belt and the material and the skirt and add this tension to the tension of the first conveyor section. The formula used for skirt tension is given under the Skirt Friction Help topic.

Scrapers and Ploughs

Enter the number of Belt Scrapers. This number is used to calculate the additional tension caused by the scraper on the belt, using the formula given in the Scrapers Help Topic.

Tension Adjustments

Tension Adjustments - You can add a tension adjustment to any section of conveyor. This adjustment may be to compensate for Hopper Pullout forces, or additional tension due to belt driven equipment.

The tension value added here is added to the calculated tension values for the conveyor section under consideration.

Brakes

To add a brake to a drive pulley is easy. Select the Pulley Data, Pulley Brakes tab sheet on the main form. In the Braking Torque Inp column, enter the value of the Low Speed Braking torque, in kNm for metric users, to apply at this pulley. The program will apply this torque during the stopping calculations and the belt tensions under braking will be calculated. You can view the stopping times on the Conveyor Dynamics report and adjust the braking torque up or down as required. You can have as many brakes as you wish in the system. The additional inertia of the brake disc should be added in Drive Inertia input field.

Refer to the Input Brake Details form for more details on brake selections.

Deleting Pulleys etc

You can delete any Pulley or item from the conveyor Profile sketch. Select the Conveyor Profile Sketch Tab sheet and then the Pulley Data, Pulley Co-ordinates table

Press the Delete Items button and move your mouse over any of the Pulleys - you will notice that the cursor changes to a "Delete" item view. Click on the intersection point or pulley on the sketch that you want to delete. You will be prompted to confirm the deletion and if you press Yes the item will be deleted from the list.

If the Item deleted is a Drive pulley, you will also be prompted to Delete the Drive linked to the Pulley, Select Yes to confirm the deletion of the drive too.

Changing Pulleys to Hoppers, Takeup etc

You can change any Pulley or item to any other type of item. Select the Conveyor Profile Sketch Tab sheet and then the Pulley Data, Pulley Co-ordinates table, find the PType column and in the Drop Down box select the Take-up (or whatever type of item you require) from the list by clicking on it. This will change the currently selected pulley to the type specified by you.

Input Material Details

Select the Duty / Input, Input Conveyed Material main menu. The following form will be displayed:

You may enter the Material details or you can press the Select a Material from Database button and then scroll down the material database to the material you require and select it by clicking in the row. Now right click with your mouse and press the Copy to Current Design file menu. The material from the database will be transferred to the design file, where you can edit the input properties if you wish.

Do not leave any input values blank - it is better to estimate a value rather than not to input one at all. Blank values may result in incorrect calculation results.

For definitions of terms refer to the follow:

Angle of Repose

Surcharge Angle

Flowability of Material

Abrasion

The maximum Incline angle is for information only - the program will still calculate a conveyor section that is steeper than this angle.

Material Lump size affects belt width. As a general rule, you should select a belt width at least three times the maximum lump size.

The Uniform Lump size option should be set if the material is uniform and mixed with fines.

Press the Tick button on the Datacontrol to save your inputs and then Exit.

Input Belt Details

Select the Duty / Input, Input Belt Details main menu. The following form will be displayed:

You may enter the Belt details or you can press the Belt Database button and then scroll down the Belt Database to the belt you require and select it by clicking in the row. Now right click with your mouse and press the Copy to Current Design file menu. The Belt from the database will be transferred to the design file, where you can edit the input properties if you wish.

Do not leave any input values blank - it is better to estimate a value rather than leave it blank. Blank values may result in incorrect calculation results.

Selecting a Belt Width

Select the Belt Category using the drop down box list. If you set the Belt Selection Mode to Manual, the form will be extended to show a list of belts in the currently selected belt category. You can now scroll down the list and right-click to select a belt.

Enter the Belt Capacity you require - this value must be at least as great as the largest capacity entered in the Conveyor Sections input table.

Enter the Allowable % Full. This figure is for future use and has no effect on the selection process.

Enter the Belt Speed. You can use the Recommended Speeds button to look up a table of recommended belt speeds. Note that as conveyor technology improves, the recommended belt speeds are increasing. Consult your idler and belt manufacturer for their recommendations if you are unsure or if you want to increase speeds beyond those given in the table.

Note regarding Belt Speed: Power absorbed is affected by the belt speed entered. An increase

in belt speed increases the power required to drive the empty belt, however, the power required to lift the load remains the same. Belt power in kW = Te x V.

Select the Idler Trough angle from the drop down box. This list shows all the trough angles in the idler database. If the trough angle you require is not listed, you will have to add it to the Idler Database

Select the Belt Width you require from the drop down list.

Press the Calc button and the program will draw the belt cross-section and calculate the % full and the edge distance. These will be displayed on the form. You can select a wider or narrower belt as required.

Enter the Top and Bottom cover thickness you require. You can press the Lookup Covers button to lookup the recommended cover thickness, based on the material characteristics.

Enter the maximum allowable Belt Sag % between idlers. If a loaded troughed belt sags too much spillage can occur. The default value is 2%. The formula used to calculate sag is:

SAG

( )y

S Wb Wm gT

=+ ⋅⋅

2

8 andy sag S=

⋅%100

where: y is the sag in mS is the idler spacing in mWb is the mass of belt in kg/mWm is the mass of load in kg/mT is the belt tension in Ng is gravitational acceleration in m/s2

The % sag is normally limited to a maximum of 5% during stopping and starting and 3% maximum during running, although many designers use 2% sag during running. Increasing allowable sag may decrease the take-up mass required (if the sag is the limiting factor), but it may also increase the effective tension as the friction may be increased. Refer to Conveyor Sections input help topic for more details.

The program will print the belt sag under the various operating conditions such as running loaded or during braking on the Belt Tension Summary Report.

Belt Mass input. You may enter a belt for the program to use. If you enter a zero value, the program will calculate the belt mass for you from the belt carcass mass plus the cover masses.

Maximum Allowable Tension Rise - This is the allowable belt tension rise during starting, usually limited to a maximum of 150% of operating tension by the belt manufacturers. This value is used to calculate the minimum starting time in seconds. Refer to the Starting Times report form for more details.

Enter the Allowable Belt Edge Tension Rise. This is the allowable tension rise in a troughed belt due to convex curve effects - the raised edge of the belt has to stretch to fit around the curved section. Refer to Vertical Curve Calculations.

Enter the Percentage Belt Mass to use for Belt Lift-off radius calculations. As the belt wears, the mass reduces and so the down force in the concave vertical curve is reduced. This input allows you to calculate the minimum curve radius required to prevent belt lift-off using a reduced or worn belt mass. Refer to Vertical Curve Calculations.

Concave Curve Safety factor - this safety factor increases the curve radius in direct proportion. For example, a factor of two will double the minimum radius.

Manual Belt Selection

It is possible to select a belt class manually. Press the Belt Selection Mode, Manual button. The form will be extended to include the current belt category data:

You can scroll down and select the belt class and strength you want by clicking in the row with the right mouse button and then using the Copy to Current Design file menu. The Belt from the database will be transferred to the design file, where you can edit the input properties if you wish.


Refer to the Belt Details design report topic for further information.

Input Take-up Details

Select the Duty / Input, Input Take-up Details main menu. The following form will be displayed:

Select the Type of take-up from the drop down list.

Click the Auto calculate Take-up mass check box to ON for Automatic calculation. The program will calculate the minimum take-up mass to limit the belt sag to the maximum specified and to prevent belt slip during running. The program will increase the take-up mass in mass steps specified in the Take-up Calculation Increment box. E.g. if you enter 500 kg it will go up in steps of 500 kg.

For Manual Take-up mass input, Switch the Auto OFF and input a take-up mass in the Manual Take-up mass edit box.

Note that the actual effective take-up mass will be slightly different to the value input by you as the take-up pulley has a Pulley Rotational Effective Tension Tp which has to be compensated for. The take-up mass input is the total mass including the mass of the take-up pulley and shaft.

Important Note:

After performing a conveyor calculation, always refer to the Drive Traction report and the Tension Summary reports to see if there is sufficient take-up tension to prevent belt slip during running, starting or braking and to prevent excessive belt sag. You can also use the Tension Graphs to see at a glance if you have low or negative tensions in the system. If, so increase the take-up mass.

Input Idler Details

Select the Duty / Input, Input Carry (or Return) Idlers main menu. The following form will be displayed:

Select the Idler Category from the Drop down box. All categories in the Idler Database will be listed.

Enter the Nominal Idler Spacing. See Recommended Idler Spacing for recommended idler spacing settings. The actual idler spacing for each conveyor section is entered in the Conveyor Sections form. This nominal spacing is used for calculating the load on the idler, the bearing life and the shaft deflection.

Select the Idler Troughing Angle, Number of Rolls, Roll Diameter and Shaft Diameter from the drop down boxes provided. The contents of these combo boxes depend on the data in the idler database.

Enter the Idler Misalignment and the Belt Deviation Load at convex curve due to curvature of belt. The default value is 500N. In a convex vertical curve, the belt tension imposes an additional load on the carry side idlers, this load being a function of the belt tension at the curve, the curve angle and the idler spacing. The program adds this load to the other idler loads imposed by the belt mass, roll rotating mass and dynamic factors. It then calculates the resulting deflections and expected bearing life for that idler.

If the conveyor does not have a convex curve, this value can be set to zero, although it is recommended that that you allow for an additional load which could be applied due to misalignment of adjacent idlers. This load is also known as the Belt Deviation Load and it can be calculated from the following formula :

Belt Deviation Load

PT D g

Ldevrun=

× × ×0 204.

where Pdev = Belt Deviation Load in NTrun = Belt Tension in kND = Misalignment of idler in mmg = gravitational acceleration in m/s2 L = idler spacing in m

Normal installations have a deviation of 3 mm on the carry side and 6 mm on the return side.

The Belt Deviation load can be calculated using the Calc button on the form, and the values transferred to the input data boxes on the left of the Calc box.

Enter the Dynamic Load Factor, Ca. The default value is 0.009. This is a factor that is added to the load on the idler roll due to movement of the load on the roll. See Recommended Idler Dynamic Load Factor.

Select the Bearing type - Ball or Roller. This alters the Bearing Life calculation.

Repeat the input process for the Return Side idlers. Note that the Dynamic Factor to input here is set to a default value of 1.4, as the type of material has no influence on the return idlers.

Automatic Idler Selection

Click the Auto option in the Idler selection Mode box if you want the program to find an idler which matches your input data (number of rolls, roll diameter, trough and shaft diameter).

Manual Idler Selection

You can let the program select the idler from the database, or you can pre-select an idler. To do this, click on the Manual option in the Selection mode box. The form will be expanded to look something like this:

Scroll down the list of idlers and right click on the idler required then press the Use this Idler for the design calculation popup menu. The selected idler will be inserted in the fields below the table

You may also type in the details of the idler if it is not in the database, or you can go to the Idler Database form and select an idler by right clicking on the database table.


Refer to the Idler Details design report topic for further information.

Input Drive Details

Select the Duty / Input, Input Drives main menu. The following form will be displayed:

This form gives a snapshot of the current drive. Click on the Drive Design Input Data tab sheet to show a table of the drives in the conveyor. This is the input data required for each drive.

The Drive Table tab sheet lists all data about a drive such as the Motors, Gearboxes etc. It is not necessary to enter all this data in this table, as the Motors, Gearbox and Fluid coupling data is captured in other input screens.

Each Drive Pulley in the Conveyor Profile and Sketch must be linked to a Drive in the Conveyor Drives list. The number of Drive pulleys in the sketch must equal the number of drives. You can have as many drives in the system as you wish. You must ensure that the Load Share for all drives totals exactly 100%.

Return to the Drive Traction Tab sheet:

Click on the type of Drive in the drop down box. The type of drive has no effect on the calculations - it is for information only.

Click on the Pulley Condition in the drop down box. The options are WET, MOIST or DRY. Each option will input a different drive co-efficient of Friction. You can override the co-efficient of friction by entering the value you require.

Choose a lagging type and enter a lagging thickness. The type of lagging also affects the suggested co-efficient of friction.

Enter the Belt wrap angle on the pulley. Make sure that this value corresponds to the value entered in the Pulley Data table form. You can use the Calculate Belt Wrap Angle form to calculate a Wrap angle if you know the layout of the Drive pulley and the snub pulley.

Enter a co-efficient of friction between belt and pulley during running conditions. The program depending on the pulley condition and type of lagging will suggest this value. The table below may be used as a guide.

Values of co-efficient of friction, u under Running conditions

Type of LaggingPulley Condition Bare Steel Rubber CeramicWet 0.10 0.20 0.25Moist 0.15 0.25 0.35Dry 0.30 0.35 0.45

For starting conditions, a higher co-efficient of friction may be used. This value is usually 0.10 more than the running co-efficient of friction.

The drive factor is calculated automatically from the Wrap angle and co-efficient of friction.

Definition of Drive Factor Cw

Cweu=

−1

1θ

where Cw is the drive factore is the base of the Naperian logu is the coefficient of friction between pulley and belt is the angle of wrap in radians

Also

CwTTe eua= =

−2 1

1 and

T T Te2 1= −

From the above, it is apparent that as the effective tension Te on a drive increases, the T2 slack side tension must be increased to prevent slippage. This means that the counterweight mass needs to be increased. Alternatively, increasing the Wrap angle will increase the contact area between belt and pulley and therefore increase the effective tension, which can be input.

Enter the estimated Drive Efficiency %. Refer to the Drive Efficiency lookup table for recommended values.

Enter the Load Share percentage for the drive. This indicates the proportion of the total effective tension that has to be input by the drive. If there is only one drive, this value should be set to 100 %. You must ensure that the Load Share for all drives totals 100%.

Starting Torque Factor for a fully loaded and empty start- this value determines the motor torque during starting. The % factor is applied to the full load motor torque. It is used to calculate the torque available from the drive to accelerate the conveyor. For a squirrel cage electric motor starting direct on line, a value of between 200% and 230% is normally used. If a fluid coupling or some other form of soft-start device is used, this value may fall as low as 130%. The lower the value, the longer the starting time and the lower the starting tensions. Refer to the Motor Database of an explanation of the Full Load torque.

Drive Inertia J - Enter the equivalent high-speed inertia of the total drive train. This should be the sum of the Motor inertia, the high speed coupling, the Gearbox inertia referred to the high speed shaft, the Fluid coupling and the brake disc and flywheel inertia. i.e. Drive Inertia = Motor + HS Coupling + Fluid Coupling + Gearbox + Brake disc + Flywheel.

The Total Drive Inertia is a very important input value as it affects the system equivalent mass and the starting and stopping belt tensions and acceleration times of the conveyor. The Drive Equivalent mass is calculated using the square of the gearbox ratio, and so changing the gearbox ratio or pulley diameter can affect the starting and stopping tensions of the conveyor. For example, a flywheel fitted on a 4 pole motor drive will have an equivalent mass of about 2.25 times [(1500/1000)^2 = 2.25 ] the same flywheel on a 6 pole motor drive and as F = ma, if you increase mass m, then acceleration rate a is reduced for the same starting torque force F. High inertia reduces starting belt tensions, and should not be over -estimated.

When a fluid coupling is fitted, you should enter only the proportion of the fluid coupling and motor inertia which has to be accelerated simultaneously with the conveyor belt, not the proportion which is accelerated before the main conveyor has to start moving.

The low speed coupling inertia (coupling between gearbox output shaft and pulley shaft) should be

added as part of the Pulley inertia, or alternatively if the device is fitted to the low speed side of the drive, the inertia is adjusted by the square of the reducer ratio to obtain an equivalent High-Speed Side inertia and then included in the Total Drive inertia value.

Moment of inertia, J mR= 2 (SI units)

where J is in kgm2m is the mass in kgR is the radius of gyration in m

You can look-up typical Moments of Inertia for AC motors in the Inertia Look-up table.

Note: Some motor manufacturers publish moment of inertia figures in MKS units as GD2 values.

J GD=

2

4See Conveyor Starting and Stopping. report for more information

The Direct Drive check box is a switch for selecting a Fluid Coupling or not. If it is set to OFF, the program will try to select a fluid coupling, if ON the program will skip the Fluid Coupling selection, but it will still use the Starting Torque % entered for the starting procedure.

It is only necessary to enter the information on the Drive Traction tab sheet in this form. Other data for Motors Gearboxes Fluid Coupling is captured in other input forms.

Refer to the Conveyor Drives design report topic for further information.

Input Motor Details

Select the Duty / Input, Input Motor Details main menu. The following form will be displayed:

Each Drive in the system must have motor selection input data entered. You can view a table list of all drives by clicking on the Drive and Motor Table tab sheet.

Select the Drive number using the Datacontrol at the top of the form.

Select the Motor Category from the Drop down box. All categories in the Motor Database will be listed. You can select motors from different categories for different drives in one conveyor design file.

Enter motor Voltage. This limits the motor selection to only motors with the voltage input.

Enter motor poles and Frequency.

Enter the Motor Selection Safety factor. The selection process involves sorting the motors by Voltage, Poles, Frequency and Power Rating and then selecting the smallest motor which meets the selection criteria. The Motor power rating required is calculated from the Belt Power at the Drive (Te x V) divided by the Drive Efficiency and then multiplied by the Motor Selection Safety factor.

For Example:

Belt Power = 100kWDrive Efficiency = 94%Motor Selection Safety Factor = 1.1

Minimum motor size = 100 / 0.94 * 1.1 = 117 kW so select next motor size (say 132 kW motor)

Number of Motors on Drive - each drive may have one or 2 or even four motors on it, depending on the gearbox arrangement. A multiple here effectively decreases the drive power but increases the number of motors required. You can use this for Tandem Drives where you may have a single drive pulley fitted with a gearbox and motor at each end of the shaft.

Manual Motor Selection

You can let the program select the smallest motor from the category that will do the job, or you can

pre-select a motor on any drive. To do this, click on the Manual Motor Selection mode option. The form will be expanded to look something like this:

Scroll down the list of motors and right click on the motor required then press the Use this Motor for the design calculation popup menu. The selected motor will be inserted in the fields below the table as well as in the Manually Selected tab sheet fields. This motor will be used for this drive.

You may also type in the details of the motor if it is not in the database, or you can go to the Motor Database form and select a motor by right clicking on the database table.


Refer to the Motor Details design report topic for further information.

Input Fluid Coupling / Soft Starter Details

Select the Duty / Input, Fluid Coupling / Soft Starter main menu. The following form will be displayed:

If there is no Fluid Coupling on the Drive, set the Direct Drive option to ON.

Each Drive in the system must have fluid coupling selection input data entered, unless there is no Fluid Coupling, in which case you should check the Direct Drive option to ON. You can view a table list of all drives by clicking on the Drive and Motor Table tab sheet.


Select the Coupling Category from the Drop down box. All categories in the Coupling Database will be listed. You can select motors from different categories for different drives in one conveyor design file.

Enter motor poles. This limits the coupling selection to only couplings with the correct speed rating.

Enter Peak Torque %. This factor limits the coupling selection to a coupling with a Peak Torque rating equal to or less than the value input.

Enter the Slip %. For fluid couplings, the efficiency is equal to 100% - Coupling Slip %. For Example, a coupling with slip = 3 % will have an efficiency of 97%.

Manual Coupling Selection

You can let the program select the smallest coupling from the category that will do the job, or you can pre-select a fluid coupling on any drive. To do this, click on the Manual Coupling Selection mode option. The form will be expanded to look something like this:

Scroll down the list of coupling and right click on the coupling required then press the Use this Coupling for the design calculation popup menu. The selected coupling will be inserted in the fields below the table as well as in the Manually Selected tab sheet fields. This coupling will be used for this drive.

You may also type in the details of the coupling if it is not in the database, or you can go to the Fluid Coupling Database form and select a coupling by right clicking on the database table.


Refer to the Fluid Coupling Details design report topic for further information.

Input Gearbox Details

Select the Duty / Input, Input Gearbox Details main menu. The following form will be displayed:

Each Drive in the system must have Gearbox selection input data entered. You can view a table list of all drives by clicking on the Drive and Motor Table tab sheet.


Select the Gearbox Category from the Drop down box. All categories in the Gearbox Database will be listed. You can select Gearboxes from different categories for different drives in one conveyor design file.

Enter the gearbox Service Factor. This factor is multiplied by the absorbed power to arrive at a design power. The torque is then calculated using the design power, and a suitable gearbox with a sufficiently high torque rating is selected from the category specified.

Enter the Speed Ratio Tolerances. The plus and minus tolerances form a selection band around the actual ratio of the gearbox. For instance, if the pulley design speed is 145 rpm, and the motor speed is 1480 rpm and the Fluid Coupling Slip is 3%, then the input speed to the gearbox would be 1480 * (1-0.03) = 1436 rpm. If the gearbox ratio were 1:10, the output speed would be 143.6 rpm. The design speed = 145 - 143.6 = 1.4 rpm. As this is less than the 5% tolerance, the gearbox is suitable.

Click on the minimum number of gearbox stages required. The program sorts the gearboxes in order of Number of stages, maximum torque rating, and ratio. If you specify 2 stages as the minimum, the program will skip single stage gearboxes in the selection process.

Manual Gearbox Selection

You can let the program select the smallest gearbox from the category that will do the job, or you can pre-select a gearbox on any drive. To do this, click on the Manual Gearbox Selection mode option. The form will be expanded to look something like this:

Scroll down the list of gearboxes and right click on the gearbox required then press the Use this Gearbox for the design calculation popup menu. The selected gearbox will be inserted in the fields below the table as well as in the Manually Selected tab sheet fields. This gearbox will be used for this drive.

You may also type in the details of the gearbox if it is not in the database, or you can go to the Gearbox Database form and select a gearbox by right clicking on the database table.


Refer to the Gearbox Details design report topic for further information.

Input Brake Details

Select the Duty / Input, Input Brake Details main menu. The following form will be displayed:

Brakes

Helix delta-T requires two inputs for each brake:

The first is the equivalent Low Speed Brake Torque to be applied at the pulley shaft.This torque is converted to a belt line force and all belt tensions are adjusted accordingly during the calculation process and a resulting stopping time is calculated and displayed on the Starting Stopping Report. Check Takeup mass and drive traction after adjusting the brake torque.

Once the low speed braking torque has been optimized you can proceed to the second stage which is to select the brake caliper and disc required to give you the low speed torque required.

Low Speed Braking Torque

To add a brake to a drive pulley is easy. Select the Pulley Data, Pulley Brakes tab sheet on the main form. In the Braking Torque Inp column, enter the value of the Low Speed Braking torque, in kNm, to apply at this drive pulley. The program will apply this torque during the stopping calculations and the belt tensions under braking will be calculated. You can view the stopping times on the Conveyor Dynamics report and adjust the braking torque up or down as required. You can have as many brakes as you wish in the system. The additional inertia of the brake disc should be added in Drive Inertia input field.

There are two inputs required for brakes:

The first is to input a Braking Torque on any Drive pulley you wish. The program will use this low speed braking torque for all the belt tension and stopping time calculations. See Pulley Input data table. The low speed torque is added to a drive pulley because we need to calculate the Drive Traction during braking. If the pulley is not a Drive Pulley but only a Low Speed brake

pulley, you must nominate it as a Drive Pulley, add a new drive in the Drives Table but allocate it a zero Load Share percentage. This ensures that it will apply the braking torque but not affect the starting of the conveyor.

In addition, you can input Brake Selection details on any Drive pulley, and the program will try to select a brake from the database to meet the selection criteria. The above form is where we input the brake selection details.

If you do not have a brake fitted on a drive set the Brake Selection Mode to No Brake on Drive. This is the default setting when you add a new drive.

You can view a table list of all drives by clicking on the Drive and Motor Table tab sheet.


Select the Brake Category from the Drop down box. All categories in the Brake Database will be listed. You can select Brakes from different categories for different drives in one conveyor design file.

Enter the Design Braking Torque. This torque is the braking torque that the brake will be required to transmit. If the Brake is fitted to the high-speed side of the drive, the torque that the brake has to input is reduced by the gearbox ratio, less any gearbox losses. You can use the following conversion from Low Speed torque to High Speed torque:

For example if the Low Speed toque is say 10 kNm, the reducer ratio is 16:1 and the Reducer Efficiency is 94% then

High Speed torque = 10 x 1000 / (16 x 0.94) = 665.9 Nm

Enter the Disc Speed of the brake. If it is a high speed brake, this would be the motor speed reduced by Fluid Coupling slip. E.g. 1450 x (1 - 0.03) = 1406.5 rpm. If the brake is a low speed brake, the disc speed should be equal to the pulley rpm. Click on the appropriate High Speed or Low Speed option button

0 To arrive at some of the brake input data, you may have to do a design calculation first and then input the brake data, such as motor speed, pulley speed etc. It may also be necessary to adjust the Low Speed braking torque input values once you have done the Brake Selection and obtained the actual braking torque which will be applied by the brake.

Enter the Disk Diameter and Disc Thickness and the Ambient Temperature. The Disc Thickness should normally be between 15mm and 50mm, and diameters from 300mm to 1000mm are common.

Enter the Design Stopping Time. This time is calculated by the program and can be viewed on the Conveyor Dynamics design report.

The number of Consecutive stops and the Average number of stops per hour are used for the thermal design calculations for the brake.

The Disc Temperature after the total number of consecutive stops will be calculated and displayed on the Brake Report form. As a rule, the brake disc temperature should not exceed 300 degrees C. If the temperature exceeds this value, you should increase the disc diameter, increase the disc thickness or select a larger brake with a larger Pad offset Width W.

Choose a Disc Material - Mild Steel (u = 0.4) or Stainless Steel. (u = 0.25). The program suggests the co-efficient of friction between pads and disc, but you may enter your own values.

Manual Brake Selection

You can let the program select the smallest brake from the category that will do the job, or you can pre-select a brake on any drive. To do this, click on the Manual Brake Selection mode option. The form will be expanded to look something like this:

Scroll down the list of brakes and right click on the brake required then press the Use this Brake for the design calculation popup menu. The selected brake will be inserted in the fields below the table as well as in the Manually Selected tab sheet fields. This brake will be used for this drive.

You may also type in the details of the brake if it is not in the database, or you can go to the Brake Database form and select a brake by right clicking on the database table.


Refer to the Brake Details design report topic for further information.

Pulley Dimensions

The Pulley Dimensions tab sheet allows you to view and input the currently selected pulley dimensions. The program will automatically select the pulley diameters and sizes from the Pulley Database unless you Override the pulley sizes and enter your own dimensions.

The pulley diameters selected by the program depend on the Belt Manufacturers recommendation for minimum pulley sizes. These minimum pulley diameters are entered in the Belt Database

Click on the Pulley Dimensions tab sheet on the main form.

After you have built your conveyor Profile and entered the Data required in the Duty / Input menu forms, you can perform a design calculation using the ISO or CEMA calculation buttons on the main form.

You can now view the pulleys selected by the program, and if you wish, adjust the dimensions as well as the Inertia of the pulley. To input your own dimensions, click in the OverrideSizes column cell and from the Drop down box select the True option. This switch sets the sizes to manual input. You can now scroll along and enter pulley and shaft dimensions. The Input values you can change are the cells with a white background colour. Greyed out cells will be automatically re-selected and calculated.

Warning: If you set the OverrideSizes to On, ensure that you input appropriate dimensions. The program will not warn you if the Pulley or Shaft sizes selected by you are unsuitable. An asterisk appears on the Pulley and Shafts report to indicate that the OverrideSizes option was used.

Setting a Minimum Pulley Diameter

It is possible to force the program to select a larger pulley than the belt needs by entering a minimum pulley diameter in the MinPulleyDia column. This forces the program to select the next available pulley sizes from the pulley database.

Rationalising Pulley Sizes

You can also use the Allow Selection switch in the Pulley Database form to rationalise your pulley sizes. By switching off pulleys in the database, the program will skip them and select the next size available. This is an easy way of forcing the program to use (say) only three pulley sizes for a whole project.

Vertical Curves

Helix delta-T allows you to input a vertical curve radius at any point along the conveyor profile. During the conveyor calculation process, the program determines if there is a vertical curve at any intersection point (Int.Pt) along the profile by checking if there is a change in slope between the preceding and following sections. If there is a change in slope, a vertical curve exists and it may be a concave or convex curve. In either case, the different curve radii required for various conveyor conditions are calculated as detailed in the Vertical Curve Calculations report.

The user may then review these curve calculations and decide on a curve radius to input at that point along the conveyor. To input a curve radius, select the Pulley Data, Vertical Curves tab sheet from the main form. Also, select the Plan & Section Scale Drawing tab sheet. The following form will be displayed.

To draw the Longsection and Plan of the Conveyor, click in the Plan and Longsection panels in turn. The lower panel shows a Longsection drawing of the conveyor.

To add a vertical curve radius at any point, select the Vertical Curve Radius column cell from the table and key in the radius required. Now click on the sketch and the curve should be drawn in red on the sketch. The curve Length should also be shown in the table. The Curve length is calculated for you and depends on the radius and the change in angle at the curve.

You can also key in the vertical curve increment (default = 20). This is the number of segments into which the curve is divided for drawing purposes.

You can see the current X and Z co-ordinates of the mouse as you move it over the Longsection drawing.

You can change the Scale of the Drawing. Click on the Scale and Origin button on the toolbar.

The following form will be displayed:

This form determines where the drawing is placed in the panel and what the horizontal (X) and vertical (Z) scales are. The scale refers to the ratio of screen pixels to real X, Z co-ordinates.

The scales are in m (or ft) per pixel.

The Origin X is the X co-ordinate to place at the left edge of the window. The Origin Z value is the Z co-ordinate of the bottom of the window. You can see this by moving your mouse to these points.

You may have to draw the conveyor using a different X and Z scales, especially if you have a long conveyor.

You can let the program determine the scales to use by pressing the Auto Calc button. Pressing the Save button saves the settings and closes the form.

Adjusting the curve radius

Under some circumstances it will be necessary to try to fit a particular curve radius into a conveyor. The Longsection form provides a powerful feedback to the designer of what combination of Intersection point co-ordinates and curve radius can be fitted into the conveyor geometry. Just Click with the Left mouse button on a curve intersection point and drag the Int. Pt on the screen. You will see the program draws the new curve in the sketch, and you will see the effect of changing the section lengths, curve radius and position of the intersection point.

The above sketch shows the Intersection Point before the first drive moved downwards and the new curve is drawn in red - it now projects beyond the drive pulley, and so you can see that it is not possible to have this radius in the curve. You can now change the radius, or you will have to re-position the curve Intersection point until the curve does fit.

Moving Pulleys and Points

The Longsection drawing allows you to physically change the position of a point or pulley. Click on the pulley or point and whilst holding the left mouse button down, drag it to the new position and release it. As you do this you will see the X, Y or Z co-ordinates changing in the table.

Changing the drawing size of the window.

You can change the drawing are size by clicking with the right mouse button in the window and pressing the Set Longsection Image size menu. You will then be prompted to enter the width of the Window in pixels. The default value is 688 pixels wide - this value matches the printout form size on the Design Reports and gives a good aspect ratio for printing, but you should experiment with the sizes which suit your system best. The next input value you will be prompted for is the depth of the Window, also in pixels. A value of about 200 to 250 usually works well.

Horizontal Curves

Helix delta-T allows you to input a Horizontal curve radius at any point along the conveyor profile. During the conveyor calculation process, if the designer has entered a Horizontal curve radius at a point, the program will calculate the belt drift and banking angle required under the different loading conditions as detailed in the Horizontal Curve Calculations report.

The user may then review these curve calculations and decide on a curve radius to input at that point along the conveyor. To Input a curve radius, select the Pulley Data, Horizontal Curves tab sheet from the main form. Also, select the Plan & Section Scale Drawing tab sheet. The following form will be displayed.

To draw the Longsection and Plan of the Conveyor, click in the Plan and Longsection panels in turn. The lower panel shows a Longsection drawing of the conveyor and the upper the plan of the conveyor.

Horizontal Curve Radius

To add a Horizontal curve radius at any point, select the Horizontal Curve Radius column cell from the table and key in the radius required. Now click on the plan sketch and the curve should be drawn in red on the sketch. The curve Length should also be shown in the table. The Curve length is calculated for you and depends on the radius and the change in angle at the curve.

You can also key in the Horizontal curve increment (default = 20). This is the number of segments into which the curve is divided for drawing purposes.

You can see the current X, Y co-ordinates of the mouse as you move it over the Plan drawing.

You can change the Scale of the Drawing. Click on the Scale and Origin button on the toolbar.

The following form will be displayed:

This form determines where the drawing is placed in the panel and what the horizontal (X) and alignment (Y) scales are. The scale refers to the ratio of screen pixels to real X, Y co-ordinates.

The scales are in m (or ft) per pixel.

The Origin X is the X co-ordinate to place at the left edge of the window. The Origin Y value is the Y co-ordinate of the bottom of the window. You can see this by moving your mouse to the edges of the window and observing the co-ordinate labels.

You may have to draw the conveyor using a different X and Y scales, especially if you have a long conveyor.

You can let the program determine the scales to use by pressing the Auto Calc button. Pressing the Save button saves the settings and closes the form.

Horizontal Curve Input data required

Curve RadiusYou must enter a curve radius. Refer the Horizontal Curve Calculations report for more details.

Belt DriftEnter the allowable belt drift in the curve. The default units are mm. The more belt drift you allow, the less the banking angle required to resist the motivating force in the curve which tends to bring the belt off the idlers on the inside of the curve. View the Reports, Horizontal Curves, Banking Angle menus.

Super Elevation AngleEnter the Super Elevation (Banking) angle in Degrees. The program will calculate the Belt Drift that results if the idlers are tilted at this angle. Perform a design calculation and then view the Reports, Horizontal Curves, Belt Drift menus. A positive Calculated Belt Drift means that the belt is creeping

up the idlers towards the centre of the horizontal curve. A negative Belt Drift value means the belt is sagging down the idler away from the Horizontal curve centre.

H Curve IncrementThis is the number of segments into which the curve is divided for drawing purposes and banking angle calculation purposes. The default value is 20.

Friction Factor us1This is the co-efficient of friction between belt and idler roller that is used to calculate the resisting force of the belt acting against the motivating force. Care should be used not to enter a value, which is too high, especially if the belt and idlers may become wet. Refer to Conveyor Drives for typical values of co-efficient friction between belt and a steel drum under various conditions such as wet, moist or dry.

Load Factor Ks and KmThese are the correction factors for the "shifting" of the load cross-sectional area on the belt as the belt drifts off line towards the centre of the curve. The default values are 1.1 and 0.9 respectively.

Adjusting the curve radius

Under some circumstances it will be necessary to try to fit a particular curve radius into a conveyor. The Plan form provides a powerful feedback to the designer of what combination of Intersection point co-ordinates and curve radius can be fitted into the conveyor geometry. Just Click with the Left mouse button on a curve intersection point and drag the Int. Pt on the screen. You will see the program draws the new curve in the sketch, and you will see the effect of changing the section lengths, curve radius and position of the intersection point.

The above sketch shows the Intersection Point before the curve moved upwards and the new curve is drawn in red. If the curve projects beyond the intersection point at the end of the section, the curve radius is too long. You can change the radius, or you will have to re-position the curve Intersection point until the curve does fit.

Moving Pulleys and Points

The Plan drawing allows you to physically change the position of a point or pulley. Click on the pulley or point and whilst holding the left mouse button down, drag it to the new position and release it. As you do this you will see the X, Y or Z co-ordinates changing in the table.

Changing the drawing size of the window.

You can change the drawing are size by clicking with the right mouse button in the window and pressing the Set Plan image size menu. You will then be prompted to enter the width of the Window in pixels. The default value is 688 pixels wide - this value matches the printout form size on the Design Reports and gives a good aspect ratio for printing, but you should experiment with the sizes

which suit your system best. The next input value you will be prompted for is the depth of the Window, also in pixels. A value of about 200 to 250 usually works well.

View Design Reports

Helix delta-T is supplied many different reports. After completing a design calculation run using the ISO or CEMA buttons on the main form toolbar, the Reports main menu will be enabled and you can then view, print or export any of the Design Reports.

Select the Reports, Design Summary main menu to view the following form

The tool bar at the top of the form allows you zoom in or out, scroll to the end or beginning of the document (if there is more than one page in the report), setup the current printer details and select which pages of the report to print, print the report or save it as a file with various file formats.

Refer to the Export Reports help topic for details on the File formats you can save the reports as.

The native Report format is a file called a QuickReport file and it has a file extension of QRP.

You can save a file as a QRP file and open it later for viewing, printing or exporting.

Note: Input data is normally shown in Italics on the Reports, with calculated data in normal upright text.

Print Design Reports



The tool bar at the top of the form allows you zoom in or out, scroll to the end or beginning of the document (if there is more than one page in the report, setup the current printer details and select which pages of the report to print, print the report or save it as a file with various file formats.

Select the Printer using the Printer Setup Button, then press the Print Button. See picture above for button details.

You can print selected pages of a report by specifying the pages in the Printer setup form.

You can also specify the number of copies of the report to print.

Refer to the Export Reports help topic for details on the File formats you can save the reports as.

Export Design Reports



The tool bar at the top of the form allows you zoom in or out, scroll to the end or beginning of the document (if there is more than one page in the report, setup the current printer details and select which pages of the report to print, print the report or save it as a file with various file formats.

You can Export a report to various file formats by using the Save File button shown above.

The file formats supported are:

File Type File Extension

Remarks

Quick Report File QRP Native file format for Design Output Reports

HTML (Web) Document HTM For Web File Deployment

Adobe Acrobat Document PDF PDF file - good format for electronic storage and email - good quality printing. Does not Require Adobe Acrobat, but does require the Free Acrobat Reader from www.adobe.com/acrobat

Rich Text Format RTF For use in most word processors including MS Word, WordPerfect

Excel Worksheet XLS Export Reports to Excel file formats. Sometimes data is not transferred accurately due to screen / font size combinations. In this case export the file as a text file and then import it into Excel

Text Document TXT Text file. Can be used as an intermediate stage between other applications / files

JPEG JPG JPEG image file

Bitmap File BMP Windows bitmap image file

Enhanced Metafile EMF Vector file - can be used to transfer to CAD packages etc.

Refer to the Print Reports help topic for details on printing the reports.

Refer to the Print Selected Reports help topic for details on printing or Export multiple reports at once.

Printing / Exporting Multiple and Selected Design Reports


Select the Reports, main menu will allow you to view and print individual reports. However, because delta-T has many reports, this can be tedious if you want to print out a whole design - don't despair, there is a way to print multiple reports at once.

Select the Reports, Print Selected Reports menu after doing a design calculation. The following form will be displayed:

The table lists the available reports for this function. To print a selection of reports, set the Report Print Column cell to True by clicking in it and selecting true form the drop down box. Now you can print all reports set to True by clicking the Print button.

If the Report Format option is set to Individual Reports, each report will be printed exactly as it appears under the Design menu option i.e. as if it was a stand-alone report.

If the Report Format option is set to Combined Reports, each report will be assembled into a composite report and then printed as a single document. The composite report will not be exactly the same as the individual reports, as some formatting may be lost. For example, reports with multiple

columns may have the Column headers omitted when the report is created. This is a limitation of the QuickReports section of the program. A work around is to print individual reports.

You can also export the selected reports to the file formats shown near the Export button. The Exported files will be saved to the Sub-directory shown in the Tree view above the Exit button. You can select the directory to export the file to before pressing the Export button.

The Preview and Print buttons at the bottom of the form only work if the Combined Report option is set to ON.

Report - Design Summary

After completing a design calculation run using the ISO or CEMA buttons on the main form toolbar, the Reports main menu will be enabled and you can then view, print or export any of the Design Reports.


This output screen summarises the salient points of your design. It shows brief details about the design, ranging from the Material Details, Conveying distance, Tensions, Installed Power, Belt and Idlers to Pulley Diameters.

The information on this report is usually sufficient for a feasibility study or a design check.

The Designers Comments section allows you to record details about the load case or other assumptions made.

Report - Tension Summary Report


Select the Reports, Tension Summary main menu to view the following form

The Running, Starting and Braking Tensions under various conditions are displayed, as well as the belt sag at the point under consideration. The 2% and 5% sag tensions are displayed. Designers would normally limit the maximum sag on the carry side of the conveyor during running to 2% and during braking to 5%. If the minimum tensions fall too low during braking, spillage of material may occur. You should inspect the tensions and increase the take-up mass if necessary.

The carry side sag tensions can be used to determine whether a suitable friction factor was input. To assist with this, the friction factor input is displayed in small letters to the left of the running tensions column and the AVERAGE sag over the section is displayed in small letters to the right of this column.

Refer to Input Conveyor Sections help topic for more details about the recommended friction factor at certain sag conditions.

Note: Negative tension values must be avoided by increasing the Take-up mass. The suggested take-up mass deficiency is shown on the report. Add this mass to the take-up mass shown at the top of the report and input this value on the Input Take-up Details form and then re-calculate.

The tension at any point should exceed the tension required to prevent excessive sag. Under normal running conditions the sag is normally limited to a maximum of 2% and under Starting and Stopping conditions to a maximum of 5%. These are input values, which you can adjust. The equivalent tension required to maintain these sag values are shown at the top of the Tension Summary form.

Excessive sag can lead to material spillage or even belt buckling and damage to the belt due to miss tracking.

Report - Take-up and Drive Traction Report


Select the Reports, Take-up & Drive Traction Report main menu to view the following form

This report indicates whether there is sufficient T2 (Slack Side) tension on the Drive pulleys to prevent belt slippage during Running, Starting and Braking conditions.

The Required T2 value is compared to the actual T2 value, and if the difference is negative the take-up mass needs to be increased. The suggested additional take-up mass is calculated and shown.

You should adjust the Take-up mass upwards by the amount shown. Use the Input Take-up Details form and then re-calculate.

Notes regarding Drives and Belt Slippage follow - also refer to the Input Drive Details form.

Co-efficient of friction between belt and pulley during running conditions. This value will be suggested by the program depending on the pulley condition and type of lagging. The table below may be used as a guide.

Values of co-efficient of friction, u under Running conditions

Type of LaggingPulley Condition Bare Steel Rubber CeramicWet 0.10 0.20 0.25Moist 0.15 0.25 0.35Dry 0.30 0.35 0.45

For starting conditions, a higher co-efficient of friction may be used. This value is usually 0.10 more than the running co-efficient of friction.

The drive factor is calculated automatically from the Wrap angle and co-efficient of friction.

Definition of Drive Factor Cw

Cweu=

−1

1θ

where Cw is the drive factore is the base of the Naperian logu is the coefficient of friction between pulley and belt is the angle of wrap in radians

Also

CwTTe eua= =

−2 1

1 and

T T Te2 1= −

From the above, it is apparent that as the effective tension Te on a drive increases, the T2 slack side tension must be increased to prevent slippage. This means that the counterweight mass needs to be increased. Alternatively, increasing the Wrap angle will increase the contact area between belt and pulley and therefor increase the effective tension which can be input.

Report - Belt Details Report


Select the Reports, Belt Details main menu to view the following form

The belt details report gives details relating to the belt strength, capacity load area etc. as well as showing a sketch of the cross-section of the load on the belt. In addition, the flooded belt load area and masses are given. This Flooded condition is when the belt is loaded up to its edge.

Standard edge distances are also given, being 5.5% of belt width plus a 20mm margin as detailed in the CEMA and ISO specifications.

You will note slight differences in load area between CEMA and ISO calculations due to different methods used by each code.

Note, it is possible to perform calculations using a belt which has full skirts or a sidewall belt - do a manual calculation of the effective load area of the sidewall or skirted belt, then adjust the belt width downwards (and adjust the material surcharge angle) until the same area is calculated by the program. Now the material mass per unit length will be correct and any tension calculations will be as for a skirted or sidewall system.

You may also add a 90 degree troughing angle idler to the database and use this for the sketch of the load area, however it is the users responsibility to ensure that the load area used by the program is the actual load area required.

Report - Idler Details Report


Select the Reports, Idler Details main menu to view the following form

A warning message will be displayed if the idler Shaft Deflection exceeds the allowable deflection.

The Load on the Centre Roll of the idler includes the load from the belt mass, material mass and the belt deviation load which may be due to idler misalignment or to a convex curve load. This belt deviation load is an input value and may be calculated on the Input Idler Details form

The Idler load also includes an Idler Dynamic Load Factor which is related to the speed of the belt and the lumps in the material and whether there is a cushioning layer of fines.

The Idler Bearing life (L10h) is calculated and the user should ensure that this L10h life is sufficient for the duty. If not, select an idler with higher load rating bearing. Normal life requirements range from 20,000 hours upwards, depending on the specifications and requirements of the project.

Report - Pulley Details Report


Select the Reports, Pulley Details main menu to view the following form

Note: Shaft length = Bearing Centres + 2 x Bearing Width + Shaft Extension Length.

Pulley diameters marked with an * indicate the pulley dimensions have been overridden and input by the user.

Refer to the Shaft Calculations help topic for details on pulley shaft calculations.

Report - Pulley Shafts Report


Select the Reports, Shaft Details main menu to view the following form


Shafts marked with an * indicate the pulley dimensions have been overridden and input by the user.


Note: For Drive pulleys, the shaft size is selected on the larger diameter of the Torsion diameter and the Deflection diameter.

Report - Pulley Sketch Report


Select the Reports, Pulley Sketch main menu to view the following form




Report - Running Fully Loaded Tensions


Select the Reports, Loading Tensions, Fully Loaded Tensions main menu to view the following form

This report shows how the tensions for this loading condition are made up:

T1 is the tight side tension on the pulley

T2 is the slack side tension on the pulley

Tp is the tension required to rotate the pulley - i.e. overcome bearing friction losses and the additional tension required to wrap the belt around the pulley. It is calculated in accordance with the CEMA Appendix 3 method.

Te is the effective tension input at a drive pulley

Material acceleration is the Tension required to accelerate the material on the belt from rest to the belt speed. Every time the program encounters an increase in capacity from one section to the next, it will automatically add this Acceleration tension.

Skirt Friction is the tension required to overcome the friction between the material and the skirts. Refer to the Skirt Friction help topic for more details.

Scraper Friction is the tension required to overcome the friction between the belt and scrapers and ploughs and other cleaning devices. Refer to the Scraper Friction help topic for more details.

Section Effective Tension is the effective tension over the section due to the belt and material moving over the idlers plus the tension required to lift (or lower) the belt and material (if applicable). Refer to the ISO Calculation help topic for more details.

The Friction Factor column shows the actual friction factor used to arrive at the effective tension over the section. This factor may be an input value, or it may be calculated using the tables described in the Input Conveyor Sections form help topic. If you input a zero friction factor for the conveyor section, then the program will calculate a value for you, using the CEMA or ISO method depending on which method you use for the calculation.

The summary panel at the bottom of the Loading Tensions report shows the minimum and maximum values, total values as well as average tensions for this loading condition. The weighted average stationary belt tension is also calculated and subtracted from the weighted average tension for this loading condition, and when the belt modulus is applied, the resulting belt elongation and take-up movement are calculated.

The Belt Power for this loading condition is also shown.

Similar reports are produced for the Belt Running Empty, Inclines and Level sections only loaded, and Declines and Level sections only loaded.

Refer to the Tension Graphs help topic to view a graph of the tensions.

Report - Belt Tensions Bar and Line Graph


Select the Reports, Tension Graphs, Bar Graph or Line Graph main menu to view the following form

These reports show, either in Bar Graph form, or in Line Graph form, the belt tensions shown on the Tension Summary Report form.

The Bar graph makes it easy to see the tensions input at each drive. You should view the graphs and ensure that there are no negative values, or values below the sag tension.

The graphs show the tensions under the different loading conditions as well as during starting, braking and coasting conditions.

Report - Vertical Curves Report


Select the Reports, Vertical Curves main menu to view the following form

Left half of report

Right half of report

The vertical curve calculation report shows the belt lift off radius calculations as well as minimum radii for limiting Edge Tension rise and Centre Tension radii at each point along the conveyor. The largest radius for Concave curves or the Minimum Radius for Convex curves for all conditions and checks is then added to the last column of the report. This radius should then be transferred back as an input into the program under the Input Vertical Curves Radius form, and a check made on the Longsection Drawing of the conveyor that this curve radius can actually fit into the geometry of the conveyor.

For concave curves, a special load case where the conveyor is loaded up the curve intersection point will usually yield the largest radius required to prevent belt lift-off. You will have to alter the conveyor capacities in the Conveyor Sections input form to simulate these conditions. The section capacity is

printed on the form for information purposes.

The last column on the report shows the maximum radius required at the intersection point, for the current loading condition. You can record comments about the loading case in the Designers Comments input box under the Project Details input form.

For Convex curve Belt Lift-off calculations, the reduced belt mass is used. i.e. the worn belt mass. The % worn is input under the Input Belt Details form.

The following formulae have been used for the curve calculations:

Concave Curves

RSWT

gBu=

minimum radius to prevent belt-lift off

where R = radius of curve in mS = safety factor (usually 1.2 to 2.0) see Input Belt Details formW = belt width in mmTu = tension at curve in kN/m - (note units - kN per m)B = worn belt mass per lineal mg = gravitational acceleration in m/s

Note: The belt tension under all possible loading conditions should be considered.

Length of curve

X RSina=

where X = Length of curve in ma = angle of incline or change of grade, in degrees

Concave Curves - Limit Edge sagging Fabric belts

( )uTnEWR

1000=

where R = radius of curve in mn = 0.222 Sin(Troughing angle)E = belt modulus in kN/mW = belt width in mmTu = belt tension at curve in kN/m

Concave Curves - Limit Edge sagging Steel belts

( )uTSinWER

12000φ×

=

where R = radius of curve in mtheta = Troughing angleE = belt modulus in kN/mW = belt width in mmTu = belt tension at curve in kN/m

Concave Curves - Maximum Centre Tension

( )ur TmTnEWR

−=

2000

where R = radius of curve in mn = 0.222 Sin(Troughing angle)E = belt modulus in kN/mW = belt width in mmm = edge tension rise factor = 1 + Edge Tension % / 100 - e.g. 1.15Tr = rated maximum operating tension for belt in kN/mTu = belt tension at curve in kN/m

Convex curves - limit edge tension rise

( )R nEW

mT Tr u

=−1000

where R = radius of curve in mn = 0.222 Sin(Troughing angle)E = belt modulus in kN/mW = belt width in mmm = edge tension rise factor = 1 + Edge Tension % / 100 - e.g. 1.15Tr = rated maximum operating tension for belt in kN/mTu = belt tension at curve in kN/m

Convex curves - to avoid centre buckling

( )R nEW

T mTu r

=−2000

where m = edge tension rise % / 100 e.g. 0.15 other variables as detailed above.

As a rule, the worst case for convex curves is when the belt is running fully loaded and the belt is new. For concave curve lift-off, the worst case is generally during starting with the belt loaded up to the concave curve and empty after the curve. If there is more than one concave curve in the conveyor, you should run different load cases for each curve loaded up to the intersection point.

See Input Belt Details for details of input requirements. Different loading conditions are entered in the Conveyor Sections input form.

Report - Horizontal Curves Report


Select the Reports, Horizontal Curves, Running Fully Loaded main menu to view the following form

The Helix delta-T program has a very powerful routine which is used to calculate the behaviour of the belt in Horizontal curves. The method of calculation involves assuming a curve radius and an allowable Belt Drift (from the centre line). The program then calculates, at user input X co-ordinate increments, the Idler Banking Angle that will be required to keep the belt from slipping off the conveyor. View the Reports, Horizontal Curves, Banking Angle menus.

Alternatively, you can enter a Super Elevation Angle (Banking angle) for each horizontal curve and the resulting Belt Drift will be calculated for each loading and operating condition. View the Reports, Horizontal Curves, Belt Drift menus. A positive Calculated Belt Drift means that the belt is creeping up the idlers towards the centre of the horizontal curve. A negative Belt Drift value means the belt is sagging down the idler away from the Horizontal curve centre. Belt Drift is limited to a maximum of the Idler Roll face width minus 1 mm.

The calculation method involves calculating the Motivating Force which is the force towards the centre of the belt curve caused by the tension in the belt at the curve.

Horizontal Curve Calculations

This motivating force has to be balanced by an equivalent force in the opposite direction, and this resisting force is created by tilting the idlers upward on the inside of the curve. This tilt angle causes the belt and material on the belt to tend to slide off the belt, in the case away from the centre of the curve. The resisting force is a component of the gravitational forces acting on the belt and the material. The amount of belt drift allowed towards the centre of the curve increases this resisting force.

In addition to the mass forces acting on the belt, there is also a frictional resistance between the belt

and idlers. However, this frictional resistance may be very low under certain conditions, such as when it is raining and the idlers and belt are wet, so we recommend that only very low co-efficient of friction values be used. The Input Horizontal Curves form has the facility to input the allowable belt drift, the curve radius, the co-efficient of friction as well as the number of curve increments to calculate.

The Horizontal curve report can be produced for all the different loading conditions, as well as for Starting, Braking and Coasting, and all of these reports should be reviewed so that worst cases are identified before deciding on the final banking angle to use.

As a general rule, the larger the Horizontal curve radius, the better. Trough Training idlers with side rollers should also be considered as a safety measure to prevent the belt drifting off centre by too much.

The return belt curves are calculated using the belt mass only (unless it is a loaded return belt). Provision is made for 1,2, 3, 4 and 5 roll idlers.

The spacing between X co-ordinate calculation increments is also an input value - enter the number of curve increments in the Horizontal Curve Input Form.

Report - Drive Details Report


Select the Reports, Drive Details main menu to view the following form

The conveyor may have as many Drives as you like - each one will be listed as for the sample above.

Backstop Torque

This report indicates whether a backstop or holdback device is required. The method used to determine this is:

Force required to Lift the load = Net lift x Mass of Matl x gHorizontal Force = Te x 1000 - Net lift x Mass of Matl x g

If LiftForce x 2 > Horizontal force then a backstop is required

The backstop torque = Drive Pulley Radius (m) x (LiftForce - HorizontalForce / 2)

The Backstop torque calculated using the above method will be a maximum when only the inclined sections of conveyor are loaded.

Note: For multiple drives, the total backstop torque required is shown at each drive motor report.

The worst case scenario for a backstop would be if the belt was restrained (jammed fast) at some point and an attempt to start the conveyor was made. In this case, the motor would deliver up to 3 times full load torque into the belt. When the overload trips, the backstop would be required to hold this torque. This value is shown on the report for information.

Refer to the Input Drive Details form for more information about drives.

Report - Motor Details Report


Select the Reports, Motor Details main menu to view the following form

Each drive motor will be listed. Motor data is extracted from the motor database. The motor efficiency and power factor are calculated from the 50%, 75% and 100% load values using a regression method.

Note: If a suitable motor is not found in the database, a warning message will be displayed during the Design Calculation. You should then either enter a motor detail manually or add a suitable motor to the database so that the program can select it.

The Motor power rating required is taken from the Belt Power x Load share % on drive divided by the Drive Efficiency input and then multiplied by the Motor Selection Safety factor. The next motor size in the database with the correct voltage, poles and frequency will be selected.

Refer to the Input Drive Details help topic for more information.

Report - Gearbox Details Report


Select the Reports, Gearbox Details main menu to view the following form

Gearbox selection and equipment details are given here. Note that if a Fluid coupling is present, the required gearbox ratio takes into account the % Slip of the Fluid coupling.

The Program sorts the gearbox database in the following order

Category, Metric, Allow Selection, No Of Stages, Max Torque, Ratio

and then selects the first gearbox which meets the requirements:

Torque Required = Motor FL Torque x Service Factor (default 1.5)Speed Required is calculated from Required Pulley speed plus or minus the Speed Selection Tolerance %.

Note that a closer speed ratio may be found by decreasing the Plus and Minus Speed ratio tolerances, and if No Gearbox Selection was possible, it could be because the program is looking for a ratio within a too narrow speed band.

Refer to the Input Gearbox Details form.

Report - Brake Details Report


Select the Reports, Brake Details main menu to view the following form

Brake selection and equipment details are given here. The Program sorts the brake database in the following order

Category, Metric, Allow Selection, Minimum Clamping Force

and then selects the first brake which meets the torque requirements:

The Disc diameter is reduced to an Effective diameter by subtracting the Pad Offset width or distance from the radius, and the braking Torque is calculated using the Clamping force, the co-efficient of friction and the effective disc radius.

The Design Stopping Time. This time is calculated by the program and can be viewed on the Conveyor Dynamics design report.

The number of Consecutive stops and the Average number of stops per hour are used for the thermal design calculations for the brake.

The Disc Temperature after the total number of consecutive stops will be calculated and displayed on the above form. As a rule, the brake disc temperature should not exceed 300 degrees C. If the temperature exceeds this value, you should increase the disc diameter, increase the disc thickness or select a larger brake with a larger Pad offset Width W.

Refer to the Input Brake Details form.

Report - Conveyor Dynamics - Starting Stopping Times Report


Select the Reports, Conveyor Dynamics main menu to view the following form

This Report summarises the Starting and Stopping time calculations for the conveyor as well as giving the mass of material that will be discharged during the conveyor stopping time.

To start a conveyor, the tension at the drives needs to overcome the resisting or 'effective tension' of the conveyor system. As long as the Tension available to start the conveyor exceeds the effective tension, the conveyor will start moving. The rate of acceleration depends on the margin between the Starting tensions and the resisting tensions.

Deceleration

The deceleration rates are calculated from the drive inertia and the inertia of the belt and material on the belt, as well as the inertia of the drives, pulleys and idlers. The deceleration rate is given by the formula

F m a= ⋅where F is the effective tension + the drive losses

m is the total moving massa is the deceleration rate

and

tVa =

where a is the deceleration rateV is the belt speedt is the starting or stopping time

The coasting distance S is given by:

S Va

=2

2The discharge mass is given by

D W Smass m= ⋅

where Wm is the mass of material per unit length ( kg/m)

Braking and Conveyor Coasting

Braking and Conveyor Coasting times are also calculated for loaded and empty conveyor conditions. The Braking force is entered as a low speed torque on the drive pulley, which is converted to a force once the drive pulley diameter has been determined. If the brake is fitted on the High Speed Side of the reducer (which is normally the case) you must convert the braking torque to a low speed torque before entering the value in the Pulley Data, Pulley Brakes table on the main form. You can do this using the following conversion.

The LS Brake Torque = HS Brake Torque * Reducer Ratio * Reducer Efficiency % / 100.

For example, HS Brake torque = 1500 Nm, reducer ratio = 18:1, reducer efficiency = 95%

LS Brake Torque = 1500 x 18 x 95 /100= 25650 Nm= 25.65 kNm which is the value that should be entered on the drive pulley.

Maximum Belt Starting Tension Percentage

This is the maximum allowable increase in belt tension during startup divided by the maximum allowable operating belt tension. It is used to calculate the maximum allowable acceleration rates during starting. The default value is 150%

This increase in starting tension multiplied by the belt rated tension minus the effective tension Te becomes the accelerating force available to start the conveyor. Using the formula F = ma and the belt speed V, an acceleration rate and thus a starting time is calculated. This starting time is compared to the starting time calculated using the allowable peak torque starting percentage (see next item) and the longest starting time of the two is chosen as the minimum starting time required. Thus, the belt starting tension percentage will only affect the conveyor allowable starting time if it is calculated to be the limiting case when compared to the motor and fluid coupling drive starting requirements.

Motor Acceleration Torque Percentage

This Percentage value limits the extent to which the peak drive torque may rise to, expressed as a percentage of the motor full load torque. The selection of the fluid coupling depends on this limitation, as the value of the peak torque percentage of the fluid coupling must be less than or equal to this percentage. See Fluid Coupling / Soft Starter for details.

The acceleration rates and starting time of the conveyor are also affected by this starting torque value. The lower the value, the lower the starting time required, provided that the allowable tension rise in the belt is not the limiting factor. (See item above)

To vary the Starting time of the conveyor, change the Starting Torque % input value on the Input Drives form.

A conveyor fitted with oversized motors may cause an excessive Tension Rise in the belt during starting. The program will issue a warning message during the calculation process if this happens.

The program allows you to input different Starting Torque percentages for a Full and Empty belt. This situation would only occur if the Startup system was specifically designed to do so. In these special cases, the Starting torque of an empty belt is lower than for a full belt (inclined conveyors).

Flywheels

The inertia of the pulleys and drives are reduced to equivalent masses and added to the belt, material, and idler rotating masses. A high inertia at a certain point will keep the belt moving for longer during stopping, and increase the starting time during starting. Fitting a flywheel at a pulley will

allow you to alter the behavior and Starting / Stopping tensions of the conveyor. A flywheel may be simulated by adding the equivalent moment of inertia of the flywheel to that of the pulley. This can be done in Pulley Dimensions input form.

The moment of inertia can be calculated as follows:



For example, the Moment of inertia of a flywheel 1m in diameter and 30mm thick would be:

kgDm 1857850030.04

=××=π

Where 7850 is the density of the steel in kg/m3

2

21 RadiusmJ ××=

So the Moment of inertia J in kgm2 is:

( ) 125.235.018521 2 =××=J

The Low Speed inertia may be calculated using the reducer ratio as follows:

2RatioHSLS inertiainertia ×=

You can look-up typical Moments of Inertia for AC motors in the Inertia Look-up table.

*************************

Datacontrol - Adding Editing, Deleting Records

Helix delta-T is supplied many places where you can add, delete or edit data.

You can use the Data Control to perform actions on your data:

The Plus button adds a new record

The Minus button deletes the current record

Click the Tick button on the Data Control to save your changes.

The Arrow buttons let you navigate up and down the table

View the Tool tips popup by hovering your mouse over the data control buttons.

If you are using one of the many data tables you can also perform the following:

Use Ctrl + Insert to insert a record

Use Ctrl + Delete to delete a record

Use Ctrl + C to copy text

Use Ctrl + V to Paste text

Right click on all Tables, Images and Drawing areas to see if there is a Popup menu available.

Material Database

Helix delta-T is supplied a list of common materials. You can also add your own material details, either to the Duty / Input Materials form, where the material will be used for the current design file, or to the Data, Material Database form. The Material can be added in either form and transferred to the other for design use or for storage in the database for future use.

To add a material to the Database, press the Data, Materials main menu. The following form will be displayed:

You can scroll down the list and select the material to use in the current design file by clicking on the row with the Right mouse button and pressing the 'Copy to Current Design file' menu. This action will send the currently selected material to the current design file.

To add a new material, navigate to the end of the list and use the down arrow on your keyboard to open a new line in the list, or press the + button on the Datacontrol to insert a new item. Now key in the data required in each column.

1. Press Add New + button on the datacontrol. A new record will be added at the end of the list. Click in the new row in the Material Description cell. Enter a Material Description. Use the Tab key or the mouse to move between records and cells.

2. Enter the material Low Bulk Density. This density is used for the belt capacity calculation and belt width selection.

3. Enter a material High Bulk Density. This value is used for the belt load support calculations and belt cover selections.

4. Enter the Maximum Recommended Belt Speed. This value is for information purposes only. If the design belt speed is higher, this value is ignored during the selection process.

5. Enter the material Maximum Lump size. If the material is uniform, i.e. it contains less than 10% fines, then click on the Uniform check box. If the material is mixed with fines and smaller lumps, leave the Uniform check box blank.

6. Enter the Angle of Repose. This is the angle at which the material stockpile sides will form.

7. Enter the Maximum Recommended Incline Angle for the material. The program will not over-ride the design process if the incline angle is larger than this value. It is for information purposes only.

8. Enter the Surcharge Angle of the material. This is the angle (from the horizontal) which the material will form during transportation. It must be less than the Angle of Repose.

9. Click on the Flowability Check Box which applies to this material.

10. Click on the Abrasion Factor Check Box which applies to this material.

11. Enter any Miscellaneous Characteristics of the material in the large text box provided. Use a new line for each characteristic. This is an optional field.

12. When all details have been entered you can use this newly added material for calculations by right clicking on the row and pressing the 'Copy to Current Design file' menu. This will save the new record and select it for use in the calculations. You can also save the newly added record by clicking on any other record in the table. Moving from one record to another automatically saves any changes you have made to the record.

Detail view of Material

The above form is accessed by clicking the Material details tab sheet. It gives a snapshot of one material at a time.

Note: The Material Lump size and Abrasion are used to select the belt covers (if Auto selection is used). So it is important to set these two parameters.

Belt Database

Helix delta-T is supplied a list of belts from various belt manufacturers. You can also add your own belt details, either to the Duty / Input Belt Details form, where the belt will be used for the current design file, or to the Data, Belt Database form. The Belt can be added in either form and transferred to the other for design use or for storage in the database for future use.

To add a belt to the Database, press the Data, Belts main menu. The following form will be displayed:

This is a list of belts in the currently selected Belt Category. You can choose to view another belt category by selecting a different category from the drop down list provided above the table.

To add a new belt, navigate to the end of the list and use the down arrow on your keyboard to open a new line in the list, or press the + button on the Datacontrol to insert a new item. Now key in the data required in each column.

You can also the Edit Menu to Insert, Copy or Delete Records. Copying records and then editing the data is sometimes a quicker way to add a range of belts than typing each individual record.

You can view or print a report listing all the belts in the category. Press the Data Report button on the toolbar.

You can Add new records by pressing the Ctrl Insert button on your keyboard.

You can Delete records by pressing the Ctrl Delete button on your keyboard.

You can view or print a report listing all the idlers in the category. Press one of the Data Report buttons on the toolbar.

You can List All Belt categories by pressing the List all button on the toolbar.

Adding or Importing Data from other applications and files

You can easily import data from MS Excel or other spreadsheet programs:

Set out the data to import in the same columns and the same format as the Database table.

Leave out formatting such as Currency symbols - add words such as True or False where applicable.

Ensure that the cells are values and not formula's - see the spreadsheet help file

Select the cells to import in the spreadsheet program

Press the Edit Copy menu in the spreadsheet program

Click on the Database Table in the Helix program to give it the Focus

Press the Paste From Clipboard button

The data will be pasted into the table.

You can also Import data from a Comma Separated file (CSV) or Export data to a CSV file using the Data Transfer menu.

A quick way to edit a whole category of data is to export the category to a CSV file, then open it in Excel, edit the data and then import the data again.

To add data manually, follow these steps.

Press Add New + button on the datacontrol. A new record will be added at the end of the list. Click in the new row in the Category Description cell and key in the Category description. This category can be any description you choose, but if it is not the same as the current category description, the new record will disappear when you save it. You will then have to select the new category from the drop down list for it to be listed. Use the Tab key or the mouse to move between records and cells.

Enter a Belt Description. Use the Tab key or the mouse to move between records and cells.

Enter the Belt Category description, Description and Class of belt. If the belt is a metric belt, set the Metric column to True. Typing a new Belt Category name will create a new belt category in the drop down list. Note that when you save a new record with a new belt category entered, it will not be displayed until you select the new category from the drop down list.

The Allow Selection column is a switch which allows you to switch the belt ON or OFF for Automatic Belt Selection purposes. If it is set to False, the belt will not be selected by the program during the selection process.

Enter the number of plies if a fabric belt. If it is a steel belt or a solid woven belt, enter a zero.

Enter the material of the reinforcing fibres. Use the words FABRIC for fabric belts, STEEL for steel belts and SOLID W for solid woven belts. Use capital letters only.

Enter the description of the belt if not already entered.

Enter the Maximum Allowable Operating Tension of the Belt. During the belt selection procedure, the program will rank all the belts in the category in ascending order of operating

tension and select the first belt that has an allowable operating tension which is higher than the maximum tension in the system. Note: This Maximum Tension is not the ultimate breaking strength of the belt, but the allowable operating stress. For example, a class 630 belt will normally have an ultimate breaking strength of 630 kN and an allowable operating tension of 63 kN, resulting in a safety factor of 10:1. In this case, enter the 63 kN in the Maximum Operating Tension column.

Enter the belt carcass thickness in mm - the thickness excluding the covers

Enter the belt carcass mass. This is the mass of the belt with zero top and bottom covers.

Enter the belt modulus in kN/m. This will be used for belt Elastic Elongation calculations.

Enter the density of the rubber covers. If unknown, a figure of 1.13 may be used.

Enter the cost of the belt covers per unit volume of rubber. This cost is added to the carcass cost to arrive at an estimate of the belt cost.

Enter the minimum pulley diameters for type A, B and C Pulleys at 61-100% of rated tension, 31-60% of rated tension and <30% of rated tension. The program will select the pulley diameters based on the calculated tension at the pulley and this minimum diameter.

PulleyType

Description

A Drive Pulleys, High Tension Head Pulley.B Tail Pulley, Bend Pulleys, Take-up Pulleys, Snub

Pulleys > 30 degree angle of wrap.C Snub Pulleys < 30 degree angle of wrap

13. Enter the maximum allowable belt width for correct load support at the material densities of 800, 1200, 1600, 2400 and 3000 kg/m3 respectively.

14. Enter the minimum belt width for correct Empty Belt Troughing at 20, 35 and 45 degree troughing angles. Note: It is possible for the program to select a belt width which can carry the tonnes per hour required, but because of the narrow width being less than that specified for correct empty belt troughing, the program rejects that belt (and class) and goes to the next belt or returns a message saying that “No belt selection was possible”. Use the manual minimum belt width override to increase the belt width selected.

The program will select an appropriate cover thickness based on the abrasiveness of the material and the belt trip rate or frequency factor. The bottom cover will be selected at 1/3 of the top cover thickness unless a minimum cover thickness is specified in the input routines. Refer to the Belt Covers help topic for more details.

To Save your changes, move to the next or the previous record, or press the Tick button on the Datacontrol.

You may also view a snapshot of a single belt record by pressing the Individual Belt Detail tab sheet.

Belt Widths and Belt Covers tabs are shown below.

Idler Database

Helix delta-T is supplied a list of idlers from various manufacturers. You can also add your own idler details, either to the Duty / Input Carry Idlers (or Return Idlers) form, where the idler will be used for the current design file, or to the Data, Idler Database form. The idler can be added in either the design form and transferred to the database for future use, or added in the database and then used in the current design.

To add an idler to the Database, press the Data, Idlers main menu. The following form will be displayed:

This is a list of idlers in the currently selected Idler Category. You can choose to view another idler category by selecting a different category from the drop down list provided above the table.

To add a new idler, navigate to the end of the list and use the down arrow on your keyboard to open a new line in the list, or press the + button on the Datacontrol to insert a new item. Now key in the data required in each column.

You can also the Edit Menu to Insert, Copy or Delete Records. Copying records and then editing the data is sometimes a quicker way to add a range of idlers than typing each individual record.




You can List All Idler categories by pressing the List all button on the toolbar.












A quick way to edit a whole category of data, is to export the category to a CSV file, then open it in Excel, edit the data and then import the data again.




Press Add New + button on the datacontrol. A new record will be added at the end of the list. Click in the new row in the Idler Category cell. Enter an Idler Category description. This idler category can be any description you choose, but if it is not the same as the current category description, the new record will disappear when you save it. You will then have to select the new category from the drop down list for it to be listed. Use the Tab key or the mouse to move between records and cells.

Enter the Idler Category description. The records are sorted alphabetically by category description.

Enter the Idler description, and Series description, Drawing number

Enter the number of idler rolls.

Enter the roll diameter in mm.

Enter the troughing angle in degrees.

Enter the shaft diameter in mm. This is also sometimes called the idler series. This value is used for shaft deflection calculations.

Enter the bearing number or designation.

Enter the bearing dynamic C rating in N. This value will be used for bearing L10h life calculations.

Click on the Carry, Return or Impact idler check box. An idler may be both a carry and return idler if required.

Move to the Idler Belt Width check boxes and click on the widths for which this idler is available. These widths are from the Belt Width database, and can be edited; however, any changes to the widths will also affect the belt database.

Now enter the roll face widths for each idler in mm.

Enter the bearing centres and support centres.

The FaceToSprtDim is the dimension from the roll face edge to the support point.

The Support Centre dimension is the Face Width plus twice the FaceToSprtDim value.

The FaceToBrgDim is the dimension from the Roll face edge to the bearing.

The Bearing Centre dimension is the Face Width minus twice the FaceToBrgDim value.

Enter the allowable shaft deflection at the bearing. This is usually a limitation of the bearing design and is between 8 to 12 minutes.

Enter the rotating mass of all the idler rolls combined i.e. the sum of the individual Roll rotating masses. (Previous versions of Helix delta-T used the individual rotating masses.)

Enter the Idler Set mass - for information only.

Enter the Fixing Width of the Idler - - for information only.

Enter the idler prices, if available, or use a zero.

The User Data cell is for any other information you may want to store.

You can save the data by pressing the Tick button on the datacontrol or by moving to another record in the table.

Detail view

You may also view a snapshot of a single idler record by pressing the Idler Details tab sheet.

This view shows a Three, Two or Single roll idler in the sketch. You may add other numbers of idler rolls such as 4 or 5 roll idlers, but the sketch will only display up to three rolls.

Pulley and Shaft Database

Helix delta-T is supplied a list of Pulleys and Shafts from various manufacturers. You can also add your own Pulley and Shaft details.

To add data to the Database, press the Data, Pulleys main menu. The following form will be displayed:

The Pulley data is separated in to Pulley Diameters, Pulley Widths and Shaft details. These three parameters are combined to make up a Pulley and Shaft combination during the selection process.

You may have as many pulley and shaft combinations as you wish. You can also add data but switch it off so that it is not used in the current selection process. To switch off a pulley or shaft, set the Allow Selection column to False by clicking in the cell and selecting False.

To add a new record, navigate to the end of the list and use the down arrow on your keyboard to open a new line in the list, or press the + button on the Datacontrol to insert a new item. Now key in the data required in each column.

You can also the Edit Menu to Insert, Copy or Delete Records. Copying records and then editing the data is sometimes a quicker way to add a range of data than typing each individual record.


















To add data manually, follow these steps.Pulley Diameters

Press Add New + button on the datacontrol. A new record will be added at the end of the list. Click in the new row in the Description cell. Enter a description. Use the Tab key or the mouse to move between records and cells.

Enter the Shell Diameter of the pulley excluding lagging. Lagging is added in the design file.

Set the Metric value to True for a metric pulley or to False for a pulley with dimensions in Inches.

Enter the Shell Thickness - this value is used to calculate the pulley inertia.

Enter the End Disc Thickness - this value is used to calculate the pulley inertia, so enter the average thickness if it has tapered end discs.

To switch off a pulley or shaft, set the Allow Selection column to False by clicking in the cell and selecting False. This will mean that the program will not select this item during the design calculations. This is a useful feature for rationalising equipment sizes, or for forcing the program to select a particular pulley.

Enter the cost of the pulley per unit mass. This cost per kg will be used to calculate a cost for the pulley in the Cost Estimating portion of the program.

Pulley Widths

Select True if the data is in metric units.

Enter the Belt Width for the pulley.

Enter the Pulley Face Width.

Key in the Bearing Centres for this pulley - this is for a pulley not mounted in a discharge chute.

Enter the bearing centres for a pulley mounted in a discharge chute. This value can be used for Head pulleys.


The User Data cell is for any other information you may want to store.

Pulley Shafts

Enter a Description for the Shaft. This is an optional input value.


Enter the Shaft Diameter at the Hub.

Enter the Shaft Diameter at the Bearing.

Key in the width of the Bearing. This value is added to the bearing centres to calculate the shaft length.

Enter the bearing designation. This value is optional and for information only.

Enter the cost of the pulley shaft per unit mass. This cost per kg will be used to calculate a cost for the pulley in the Cost Estimating portion of the program.

Enter the cost of the bearing. Two bearings are added for the shaft costing.


Motor Database

Helix delta-T is supplied a list of Motors from various manufacturers. You can also add your own motor details, either to the Duty / Input Motors form, where the motor will be used for the current design file, or to the Data, Motor Database form. The motor can be added in either the design form and transferred to the database for future use, or added in the database and then used in the current design.

To add a motor to the Database, press the Data, Motors main menu. The following form will be displayed:

This is a list of motors in the currently selected Motor Category. You can choose to view another motor category by selecting a different category from the drop down list provided above the table.

To add a new motor, navigate to the end of the list and use the down arrow on your keyboard to open a new line in the list, or press the + button on the Datacontrol to insert a new item. Now key in the data required in each column.




You can view or print a report listing all the motors in the category. Press one of the Data Report buttons on the toolbar.

You can List All Motor categories by pressing the List all button on the toolbar.
















Press Add New + button on the datacontrol. A new record will be added at the end of the list. Click in the new row in the Motor Category cell. Enter a Motor Category description. This motor category can be any description you choose, but if it is not the same as the current category description, the new record will disappear when you save it. You will then have to select the new category from the drop down list for it to be listed. Use the Tab key or the mouse to move between records and cells.

Enter the Motor Category description. The records are sorted alphabetically by category description, then by Number of Poles, Voltage and Power Rating.

Enter the Motor description.


To switch off a motor, set the Allow Selection column to False by clicking in the cell and selecting False. This will mean that the program will not select this item during the design calculations. This is a useful feature for rationalising equipment sizes, or for forcing the program to select a particular motor.

Enter the Voltage, Poles, Power Rating, Speed etc. All data should be entered as blank values

may cause an error during the design calculations. If you do not know a value, enter an estimate or 9999 or some other value you can recognise as a dummy value.

The actual running speed n is where the Motor Torque and Load Torque curves intersect.

Moment of Inertia of motor

The motor manufacturer will normally supply the Moment of Inertia of the motor rotor. However, if this is not available, the Moment of Inertia Look-up table may be used as a guide.

Detail view

You may also view a snapshot of a single record by pressing the Motor Details tab sheet.

Gearbox Database

Helix delta-T is supplied a list of Gearboxes from various manufacturers. You can also add your own Gearbox details, either to the Duty / Input Gearbox form, where the Gearbox will be used for the current design file, or to the Data, Gearbox Database form. The Gearbox can be added in either the design form and transferred to the database for future use, or added in the database and then used in the current design.

To add a Gearbox to the Database, press the Data, Gearboxes main menu. The following form will be displayed:

This is a list of Gearboxes in the currently selected Gearbox Category. You can choose to view another Gearbox category by selecting a different category from the drop down list provided above the table.

To add a new Gearbox, navigate to the end of the list and use the down arrow on your keyboard to open a new line in the list, or press the + button on the Datacontrol to insert a new item. Now key in the data required in each column.




You can view or print a report listing all the Gearboxes in the category. Press one of the Data Report buttons on the toolbar.

You can List All Gearbox categories by pressing the List all button on the toolbar.
















Press Add New + button on the datacontrol. A new record will be added at the end of the list. Click in the new row in the Gearbox Category cell. Enter a Gearbox Category description. This Gearbox category can be any description you choose, but if it is not the same as the current category description, the new record will disappear when you save it. You will then have to select the new category from the drop down list for it to be listed. Use the Tab key or the mouse to move between records and cells.

Enter the Gearbox Category description. The records are sorted alphabetically by category description, then by Number of Stages, Maximum Torque Rating and then Ratio.

Enter the Gearbox description and Type.


To switch off a Gearbox, set the Allow Selection column to False by clicking in the cell and selecting False. This will mean that the program will not select this item during the design calculations. This is a useful feature for rationalising equipment sizes, or for forcing the program to select a particular Gearbox.

Enter the Code, Size, Number of Stages and Ratio of the gearbox. All data should be entered as blank values may cause an error during the design calculations. If you do not know a value, enter an estimate or 9999 or some other value you can recognize as a dummy value.

The Max Input Speed and Min Input Speed is the speed range of the motor. A gearbox will not

be selected if the motor speed falls outside this range.

Enter the Moment of Inertia in the MomI column if you have this value. If not, you may leave it blank.

Detail view

You may also view a snapshot of a single record by pressing the Gearbox Details tab sheet.

Brake Database

Helix delta-T is supplied a list of Brakes from various manufacturers. You can also add your own Brake details, either to the Duty / Input Brake form, where the Brake will be used for the current design file, or to the Data, Brake Database form. The Brake can be added in either the design form and transferred to the database for future use, or added in the database and then used in the current design.

To add a Brake to the Database, press the Data, Brakes main menu. The following form will be displayed:

This is a list of Brakes in the currently selected Brake Category. You can choose to view another Brake category by selecting a different category from the drop down list provided above the table.

To add a new Brake, navigate to the end of the list and use the down arrow on your keyboard to open a new line in the list, or press the + button on the Datacontrol to insert a new item. Now key in the data required in each column.




You can view or print a report listing all the Brakes in the category. Press one of the Data Report buttons on the toolbar.

You can List All Brake categories by pressing the List all button on the toolbar.
















Press Add New + button on the datacontrol. A new record will be added at the end of the list. Click in the new row in the Brake Category cell. Enter a Brake Category description. This Brake category can be any description you choose, but if it is not the same as the current category description, the new record will disappear when you save it. You will then have to select the new category from the drop down list for it to be listed. Use the Tab key or the mouse to move between records and cells.

Enter the Gearbox Category description. The records are sorted alphabetically by category description, then by Minimum Clamping Force.

Enter the Brake description and Caliper description.


To switch off a Brake, set the Allow Selection column to False by clicking in the cell and selecting False. This will mean that the program will not select this item during the design calculations. This is a useful feature for rationalising equipment sizes, or for forcing the program to select a particular brake.

Enter the Caliper Size, Minimum Clamping Force of the brake, Loss of Force per mm of gap, Maximum allowable air Gap, and the Pad offset distance.

The other input data is for information only and may be omitted if you wish.

Detail view

You may also view a snapshot of a single record by pressing the Brake Details tab sheet.

Cost Estimating

You can build up cost estimate for the conveyor, including Engineering and Design costs, Civil works, Mechanical, Electrical and Installation and Commissioning costs for the conveyor.

Select the Estimating, Conveyor Cost Estimate menu from the main form. The following form will be displayed:

The Estimating system consists of a two-table system. The top table contains Cost Categories, and each category can have as many Cost Items associated within it.

To add a new cost category, navigate to the end of the list and use the down arrow on your keyboard to open a new line in the list, or press the + button on the Datacontrol to insert a new item. Now key in the data required in each column.

Once you have added a new category and saved it, the bottom table will reflect all items associated with that category (-usually none, for a new category). You can now add items in the bottom table, ensuring that you link the items to the Category by using the same description in the category columns of each table. The Auto Add Category name option will ensure that the Category name is automatically added in the items table each time you add a new item

You can view or print a report listing all the Cost items in all the categories. Press the Data Report button on the toolbar.














A quick way to edit a whole category of data is to export the category to a CSV file, then open it in Excel, edit the data and then import the data again.

Extracting Equipment and Cost Data from the current design File

Right click in the Cost Items table. The following popup menu will appear:

The Popup menu allows you to perform a whole range of activities such as Factoring All Prices, Pasting data etc. The Factor Prices menu allows you to adjust all prices in the current category by a factor.

The Margin % column in the Categories table allows you to enter a Gross Margin % to add to the costs. This can be used for calculating a Selling Price for conveyor system

This menu also allows you to extract cost data from the current conveyor design file. You can get the motors, gearboxes, fluid couplings, belts, idlers and Pulley and shaft costs. The actual quantities in the design file will be extracted and merged with the costs from the Database files. You can change the quantities and cost rates if you wish, after importing them from the design file.

You can view or print a report listing all the Cost Items in the Estimate. Press one of the Data Report buttons on the toolbar. The Cost Report will be created and displayed. You can Print or Export this report.

Equipment Schedules

After doing a number of Conveyor Design Calculations you may want to construct equipment schedules. These schedules summarise the equipment from a number of designs onto one report. For instance, you may do 5 conveyor designs and then construct a schedule showing the Belt details for the 5 conveyors on one report. Equipment schedules are also provided for Idlers, Motors, Pulleys, Fluid Couplings and Gearboxes.

In addition, you can set up a Project Design Summary Report. This is a summary of the main conveyor design features from any number of conveyors, such as belt details, speed, capacity etc. You can export this report to PDF, Word (RTF) Excel etc. and use it as basis for your own customised reports.

To construct Equipment Schedules, first do your conveyor designs. Each design should be done in a New Conveyor Design File.

Select the Equipment Schedules main menu option. The following from will be displayed.

How to Construct an Equipment Schedule

Select the subdirectory in which the design files are stored. This will usually be in the Projects subdirectory. You can use the Directory Tree list provided to do this.

Select the design files you want to include in the reports. You can double click on a file in the file list to add it the schedule list at the bottom of the form, or select multiple files using the Ctrl button and your mouse and then press the Add File to Schedule List button. Ensure that the full path of the file is in the Schedule list, not just the file name.

Click on the Equipment Schedule required in the group on the top right hand corner of the form.

Press the View / Print Schedule button. The program will now construct the schedule and display it.

To create a new report for different equipment for the same group of designs, click on the report type required and press the View / Print Schedule button.

These schedules may be used for cost estimates, pricing, faxing to suppliers for prices or just for record purposes.

Sample of Equipment Schedule - Conveyor Summary Report

One of the most useful Equipment schedules is the Pulley Schedule - sample shown below:

ISO Calculation Method

The ISO Tension calculation is based on:

( ) ( )[ ]T C f L g Q Q Q Q Cos Alpha Q H g F Fro ru b g g s s= ⋅ ⋅ ⋅ + + ⋅ + ⋅ + ⋅ ⋅ + +2 1 2

where T is the tension in NC is the adjustment factor for secondary resistancesf is the artificial friction coefficientL is the conveying distance in mg is gravitational acceleration in m/s2Qro is the rotating mass of the troughing idlers in kg/mQru is the rotating mass of return idlers in kg/mQb is the belt mass in kg/mQg is the mass of material in kg/mH is the vertical lift in mFs1 are the special main resistances in NFs2 are the secondary resistances in NAlpha is the incline angle

The ISO method of calculation uses a so-called C factor to compensate for secondary losses. This is a factor by which the tensions are adjusted upwards to allow for secondary resistance’s such as pulley inertia etc. On short conveyors, the C factor is relatively high because the proportion of secondary resistance’s to the total resistance’s is high, however on long conveyors (over 2000m ) this factor tends to be equal to 1.05.

The formula used for calculating C is:

[ ]CLn LL

=⋅

+17

1

where C is the adjustment factorLn is the natural logarithm = log to the base eL is the conveying distance in m

The Helix delta-T program does not use the C factor as all secondary resistance's such as Scrapers, Pulley Rotation, Skirts, Material Acceleration etc. are calculated each time a calculation is performed.

Refer to ISO 5048 for further details.

Skirt Friction

The program will calculate the additional tension due to friction between the skirt and the belt and the material and the skirt and add this tension to the tension of the first conveyor section.

Ts u I r L gV b

=⋅ ⋅ ⋅ ⋅

⋅

2

2 2See ISO 5048 and DIN 22101

where Ts is the skirt resistance in Nu is the coefficient of friction between material and belt - usually 0.5 - 0.7I is the conveyor capacity in m3/sL is the length of skirt in mV is the belt speed in m/sr is the material density in kg/m3b is the effective width of skirt = 2/3 belt width

Scraper Resistance's

The following formula is used to calculate the additional tension caused by the scraper (or ploughs) on the belt.

Ts n W g=

⋅ ⋅254.

where Ts is the scraper tension in Nn is the number of scraper bladesW is the belt width in mmg is gravitational acceleration in m/s2

Hopper or Feeder Pullout Forces

You can calculate the additional forces required to pull material out of a hopper or bin. Select the Calcs, Hopper Pullout Forces menu from the main form. The following form will be displayed:

This form allows you to calculate the Additional Tension required to pull a material out of a hopper. We use the term additional tension, because the forces calculated here are not the normal running tensions of the feeder, but the extra tension required to pull the material out of the hopper.

Once you have the magnitude of these Pullout force tensions, you should design the Feeder as a normal conveyor and add the Pullout Tension as a Tension Adjustment in the Conveyor Sections form.

Two methods of calculation are offered - Bruff's method and the method proposed in the Bridgestone conveyor design manual. Generally, Bruff's method is more conservative and is the preferred choice for safety.

You will note that two Tensions are given:

Starting or Initial Pull-out forceRunning or Flow conditions Pullout force.

The higher Starting force is required to overcome the interlocking (or bridging) of the material whilst stationary. Once it is flowing, the force required reduces.

After Calculations are done you can view, Print or Export the following report:

Discharge Trajectory

You can calculate the Trajectory of the material as it leaves the head pulley of a conveyor. Select the Calcs, Discharge Trajectory menu from the main form. The following form will be displayed:

This form allows you to calculate the X, Y position of a particle discharged from the belt. The main inputs required are the Belt Speed, The discharge Radius from the centre of the pulley to the particle sitting on the belt, the angle of the belt incline (minus for decline) at the discharge pulley, and a time period.

Enter your conveyor parameters and press the Calc button. You can save your settings by using the Datacontrol buttons.

You can input two discharge radii - one for a particle sitting at the belt line and one for a particle (a lump say) which is on top of the material on the belt. This system yields an 'envelope' which should cover the spread of the material (ignoring wind etc) during its path towards the ground.

The Time after discharge is broken into the number of Calc increments you input and the program calculates the relative X and Y co-ordinates of the particle, relative to the Pulley Centre line, at these time increments.

The X and Y co-ordinates can be viewed and printed by selecting the Print, Print Co-ordinate menu option:

The program calculates the point at which the particle will leave the belt which is wrapped around the pulley. If the pulley is moving relatively slowly, the particle will not be leaving belt immediately to begin its fall, but will be carried around the perimeter of the pulley / belt to some point until gravitational force causes it to begin its fall.

This phenomenon, can cause a lump perched on top of the material, to actually begin falling before a particle which was sitting directly beneath it on the belt line at time t = 0, because it is effectively hanging out further. This is a sort of avalanche effect. This can make the discharge lines cross paths.

Bearing Life L10h

Idler and pulley shaft bearing life calculations are performed using the L10h bearing life formula.

The bearing life is calculated as follows:

Where L10h is the basic rating life in hoursC is the dynamic load rating of the bearing in NP is the load on the bearing in N (half the pulley load)P = 3 for ball bearingsP=10/3 for roller bearingsN is rotational speed in rpm

Shaft Calculations

Idler and pulley shaft bearing life calculations are performed using the L10h bearing life formula.

The shaft calculations are based on the running tensions using the following formulae:(Consult your pulley manufacturer for final shaft sizing)

Resultant Force on shaft

( )R T T CosT T= + − ⋅ ⋅ ⋅12

22

1 22 2 θ

where R is the resultant force on the pulley in kNT1 is the tight side tension in kN T2 is the slack side tension in kNtheta is the angle of wrap of the belt on the pulley

The Deflection Diameter is given by:

( )DE Tan

R a L ad = ⋅ ⋅⋅

⋅⋅ − ⋅

644

24π α

where Dd is the deflection diameter in mmE is the Modulus of Elasticity = 210000 Mpaalpha is the allowable angular deflection in minutes - default is 5 minutesR is the resultant force on the shaft in NL is the bearing centres in mm

a =Bearing Centres - Pulley Hub Centres

2 in mmNote that pulley hub centres are assumed to be the same as the belt width on the pulley.

The combined stress formula used is :

T Pn

=⋅ ⋅⋅ ⋅60 10

2

6

πwhere T is the torque in Nmm

P is the installed power in kWn is the pulley rotational speed in rpm

The bending moment is given by

M R a=

⋅2

where M is the bending moment in NmmR is the resultant force

a =Bearing Centres - Pulley Hub Centres

2 in mm

Minimum shaft Diameter combined stresses Dt

( )Dt M M T=⋅

⋅ + +16 2 223

π Allowable Stresswhere all symbols are as detailed above. Refer to The Machinery’s Handbook or similar for more details.

The allowable stress is usually taken to be 41 Mpa for axle steels and 55Mpa for higher strength K4140 steels.

Consult your pulley manufacturer before finalising shaft details.

The program allows a margin of 3mm on the diameter calculated to the diameter selected. For example, if the diameter calculated is 127.9 mm and there is 125mm shaft in the database, the 125mm will be selected. This is to prevent the program from oversizing the shaft when the calculated diameter is only marginally larger than the shaft diameters available.


Temperature Correction Factor

Cold weather increases the Idler Frictional resistances as well as the flexing resistance of the Belt during operation. This increased friction is catered for by multiplying the normal Friction Factor values by a factor Kt. Details of the Kt values versus temperature are given in the CEMA manual.

To apply a Temperature correction factor, Select the Duty / Input, Input Project details main menu. The Project Details form allows you to enter a minimum expected site temperature, and a Kt factor is calculated. This Kt factor is applied to the Friction factor calculated.

The charts show how Kt varies with temperature. Note that only temperatures below freezing point result in a Kt value larger than 1.

Special grease for idlers and bearings may be required for operation at temperatures below -15 degrees F (-26 deg C). Conveyor belting may also be affected. Check with equipment suppliers.

In high ambient temperature regions, the power required to drive the conveyor is not affected, but there may be limits on motor and gearbox operations. Again, check with suppliers on the thermal ratings of equipment for temperatures above 35 deg C.

Angle of Repose

The Angle of Repose of a material is the angle that the sides of a stockpile of the material makes with the horizontal plane. See also Surcharge Angle

General Characteristics of Materials, Flowability, Surcharge Angle and Angle of Repose

Very FreeFlowing

Free Flowing Average Flowing Sluggish

5 deg Angle ofSurcharge

10 deg Angleof Surcharge




0 -19 degAngle ofRepose


30 -34 degAngle of Repose


> 40 degAngle ofRepose

Material CharacteristicsUniform size,

very smallroundedparticles,

either wet orvery dry, suchas dry silica

sand, cement,wet concrete.

Rounded, drypolished

particles ofmedium

weight, such aswhole grainand beans

Irregular,granular or

lumpy materialsof medium

weight, such asanthracite coal,

cottonseedmeal, clay

Typicalcommon

materials suchas bituminouscoal, stone,most ores.

Irregular,stringy,fibrous,

interlockingmaterial, such

as woodchips,

bagasse,tempered

foundry sand.

Surcharge Angle

The Surcharge Angle of a Material is the Angle of the Slope of the material, measured from the horizontal, that it makes when on a moving conveyor belt. The Surcharge angle is usually between 5 to 15 degrees less than the Angle of Repose of the material.


Very FreeFlowing

















particles ofmedium






Typicalcommon




as woodchips,

bagasse,tempered

foundry sand.

Flowability of Material

The Flowability of a Material is an indication of the load cross-section which a material forms during transportation on a moving conveyor belt. Small, rounded particles are freer flowing than angular sharp particles which interlock.


Very FreeFlowing

















particles ofmedium






Typicalcommon




as woodchips,

bagasse,tempered

foundry sand.

Reference: Belt Conveyors for Bulk Materials - CEMA, 2nd Edition, pg. 39

Abrasion Factor

The Abrasion factor is used in the cover selection of the belt.

Minimum Belt Cover Thickness is listed in the following table. The program uses these parameters for the automatic belt cover thickness calculation, and then searches the belt database and selects the first cover thickness equal to or larger than this value. The bottom cover is selected as one third of the thickness of the top cover.

FrequencyFactor LV

=⋅2

(sometimes called “Trip Rate”)

where Frequency Factor is in secondsL = Conveying distance in mV = Belt Speed in m/s

Minimum Belt Top Covers in mmFreq.Factor

No Abrasion or LightAbrasion

Medium Abrasion Heavy Abrasion

Lump Size, mm12 50 150 >150 12 50 150 >150 12 50 150 >150

12 1.6 3.0 6.3 8.0 3.2 6.3 10 10 8.0 10 10 1025 1.6 2.5 3.2 5.0 2.5 3.2 6.3 10 4.0 8.0 10 1040 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 4.0 8.0 1060 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 6.3 1090 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 6.3 6.3120 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 5.0 6.3180 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 5.0 6.3240 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 5.0 6.3

Belt Cover Thickness

The Abrasion factor is used in the cover selection of the belt.

Minimum Belt Cover Thickness is listed in the following table. The program uses these parameters for the automatic belt cover thickness calculation, and then searches the belt database and selects the first cover thickness equal to or larger than this value. The bottom cover is selected as one third of the thickness of the top cover.

FrequencyFactor LV

=⋅2

(sometimes called “Trip Rate”)

where Frequency Factor is in secondsL = Conveying distance in mV = Belt Speed in m/s

Minimum Belt Top Covers in mmFreq.Factor

No Abrasion or LightAbrasion

Medium Abrasion Heavy Abrasion

Lump Size, mm12 50 150 >150 12 50 150 >150 12 50 150 >150

12 1.6 3.0 6.3 8.0 3.2 6.3 10 10 8.0 10 10 1025 1.6 2.5 3.2 5.0 2.5 3.2 6.3 10 4.0 8.0 10 1040 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 4.0 8.0 1060 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 6.3 1090 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 6.3 6.3120 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 5.0 6.3180 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 5.0 6.3240 1.6 2.5 3.2 5.0 2.5 3.2 4.0 5.0 3.2 3.2 5.0 6.3

The bottom cover is usually taken as one third of the top cover thickness.

Idler Spacing

Recommended Idler spacing is shown in the table below:

SUGGESTED NORMAL SPACING OF BELT IDLERS.Belt

Widthmm

Troughing Idler Spacing in m

Bulk Density of Material in kg/m3

ReturnIdler

Spacing500 800 1200 1600 2400 3200

450 1.7 1.5 1.5 1.5 1.4 1.4 3.0600 1.5 1.4 1.4 1.2 1.2 1.2 3.0750 1.5 1.4 1.4 1.2 1.2 1.2 3.0900 1.5 1.4 1.2 1.2 1.0 1.0 3.0

1050 1.4 1.4 1.2 1.0 0.9 0.9 3.0

1200 1.4 1.4 1.2 1.0 0.9 0.9 3.01350 1.4 1.2 1.0 1.0 0.9 0.9 3.01500 1.2 1.2 1.0 0.9 0.9 0.9 3.01650 1.2 1.0 1.0 0.9 0.75 0.75 2.4

1800 1.2 1.0 1.0 0.9 0.75 0.75 2.42100 1.0 1.0 0.9 0.75 0.75 0.60 2.42400 1.0 1.0 0.9 0.75 0.60 0.60 2.4

Source: CEMA Handbook, 2nd Edition, Pg. 68

Idler Dynamic Load Factor

Recommended Idler Dynamic Load Factors are shown in the table below:

Dynamic Load Factor, CaType of Bulk Material Fixed Idler Set Suspended Idler Set

Fine-grained Material 0 0Individual small chips 0.005 0Coarse Chips on layer of cushioning material 0.009 0.005Coarse Chips without layer of cushioning material

0.014 0.009

Exclusively Coarse lumps weighing up to 100kg 0.050 0.02

The Dynamic Factor is calculated from :

F Ca V= + ⋅1 2

where F is the Dynamic load factorCa is the Factor from the table aboveV is the belt speed in m/s

The dynamic factor F is multiplied by the load on the idler roll imposed by the mass of the material on the roll.

Gearbox Efficiencies

Mechanical Efficiencies of speed reduction equipment.

Type of ReducerApproximateEfficiency %

V belts and pulleys 94%Roller Chain and cut sprockets, open guard 93%Roller Chain and cut sprockets, oil bath lubrication 95%Single Reduction Helical Gear reducer 95%Double Reduction Helical Gear reducer 94%Triple Reduction Helical Gear reducer 93%Worm Gear Reducers (20:1 ratio) 90%Worm Gear Reducers (20:1 to 60:1 ratio) 70%Worm Gear Reducers (60:1 to 100:1 ratio) 50%Cut Spur Gears 90%Cast Spur Gears 85%

Source: CEMA handbook, Fenner Power Transmission Handbook

Recommended Maximum Belt Speeds

Recommended Maximum Belt Speeds are given in the table below:

RECOMMENDED MAXIMUM BELT SPEEDS - CEMA MANUAL

MATERIAL BEING CONVEYEDBELT SPEED BELT

WIDTHm/s mm

Grain or other free flowing non-abrasive material

2.53.545

450750

10502400

Coal, damp clay, soft ores, overburden and earth, fine crushed stone

2345

450900

15002400

Heavy, hard, sharp-edged ore, coarse-crushed stone

1.82.53

450900

>900

Foundry sand, prepared or damp, shakeout sand with small cores, with or without small castings (not hot enough to harm belting)

1.8 Any Width

Prepared foundry sand and similar damp (or dry abrasive) materials discharged from belt by rubber-edged plows

1.0 Any Width

Non-abrasive materials discharged from belt by means of plows.

1.0,except forwood pulp

where 2.0 ispreferable

Any Width

Feeder belts, flat or troughed, for feeding fine, non-abrasive, or mildly abrasive materials from hoppers and bins.

0.25 - 0.50 Any Width

Take-up Travel or Stroke

The take-up stroke or movement depends on a number factors including Belt Elastic Elongation, Permanent Belt Stretch and Initial Belt stretch. The following table gives a guideline on take-up travel distances which should be allowed:

Screw or Manual Take-up

Minimum Take-up Travel in % of Centre Distance

Fastened joints Vulcanised Splices

Operating Tension 100% of RatedTension

75% of RatedTension

100% of RatedTension

75% of RatedTension

Belt Type

All Fabric Belts 1.5% 1% 4% 3%

Automatic or Gravity Take-up

Minimum Take-up Travel in % of Centre Distance

Fastened joints Vulcanised Splices

Operating Tension 100% of RatedTension

75% of RatedTension

100% of RatedTension

75% of RatedTension

Belt Type

Fabric - Cotton Fibre 1.5% 1% 4% 3%

Fabric - Cotton / Nylon 2% 1.5% 2.5% + 0.65m 2% + 0.65m

Fabric - Rayon / Nylon 1% 1% 1.5% + 0.65m 1% + 0.65m

Fabric - Nylon 2% 1.5% 2.5% + 0.65m 2.5% + 0.65m

Steel Cable - - 0.25% + SpliceLength

0.25% + SpliceLength

You can refer to the Loading Tension Reports for details of the take-up movement due to Elastic Elongation of the belt due to tension changes between stationary and operating conditions.

Moment of Inertia, AC Motors

The following table lists typical Rotor inertia values for AC Electric motors. As a guide, these values can be multiplied by 1.25 and used as the Input Value for Drive Inertia, if exact figures are not available.

J moment of Inertia AC motorsPower

kW

Moment of Inertia [ kgm2] for different rpm

3000 rpm 1500 rpm 1000 rpm 750 rpm

11 0.055 0.065 0.1 0.25

22 0.13 0.24 0.33 0.73

30 0.19 0.35 0.73 0.9

45 0.31 0.43 1.2 1.7

55 0.6 0.7 1.5 2.4

75 1.2 1.2 2.4 3.2

90 1.4 1.4 2.9 4.0

110 2.2 2 3.5 6.0

250 3.7 5.6 9.1 13

Note: Some motor manufacturers publish moment of inertia figures in MKS units as GD2 values. These should be converted to J values as follows.

J GD=

2

4

Note that values for DC motors and Wound Rotor motors may vary significantly from these values which are supplied as a guide only. Consult the manufacturer for exact details.



For example, the Moment of inertia of a flywheel 1m in diameter and 30mm thick would be:

2

21 RadiusmJ ××=

5.0=Radius

kgDm 1857850030.04

=××=π

Where 7850 is the density of the steel in kg/m3

So the Moment of inertia J in kgm2 is:

( ) 125.235.018521 2 =××=J

The Low Speed inertia may be calculated using the reducer ratio as follows:

2RatioHSLS inertiainertia ×=

Viscoelastic friction factor calculation method

Introduction

Friction factor fConveyor resistances have traditionally been estimated using a Coulomb friction factor applied to the mass per m of the load and conveyor belt.

where u is the co-efficient of friction, m is mass and g is 9.81m/s2

This friction factor is usually estimated to be between 0.015 and 0.035. Use of the ISO and CEMA buttons in the Helix delta-T program will use the appropriate friction factor calculated in accordance with CEMA tables or the belt sag vs f factor tables shown in the Helix help file topic called Input Sections

You can also override the Automatic friction factor calculation by inputting the value you want to use for each Section on the Sections tab sheet, in the f.

Long level conveyorsWhilst the above methods work very well for in-plant and inclined conveyors, there is evidence from existing conveyor installations, that if the conveyor is very long (say more than 4km) and does not have a large vertical lift and is operating in a hot climate, the traditional methods have been known to yield a friction factor which is higher than measured friction factor. For example, the Channar 10km long conveyor operated by Rio Tinto in Western Australia has been measured to have an equivalent friction factor of about 0.011 under some operating conditions. This low friction factor results in a much lower power requirement, in the Channar case the conveyor can operate with two drives totaling 1400kW whereas the traditional methods predicted a power requirement of 3 drives totaling 2100kW.

It is apparent that the large discrepancy on long conveyors between conventional methods and actual measured values is due to the cumulative effects a large number of small variations between the predicted and actual friction factors for the conveyor. On short conveyors, the errors are not significant, but on long ones, where the bulk of the power required goes into overcoming internal conveyor friction and not on lifting the load, the errors accumulate until they are significant.

Much research has been undertaken and many papers have been published on the subject - See References in this help file for details.

Helix Technologies have reviewed these papers, and with assistance of consultants and other Engineers, formulated a method of calculating and predicting the friction factor for these conveyors. This method has been incorporated in the program and can be used to refine the friction factor estimate for the conveyor. This calculation method is intended to allow the design engineer to justify the use of a particular friction factor based on making up the friction factor based on known input data, rather than relying purely on experience and judgment to decide on a friction factor.

Main Conveyor ResistancesIn this Helix delta-T program we deal with four main components of the conveyor resistance. These are:

Belt to Idler Indentation resistance - fi

Belt and Material Flexure Resistance- fm

Idler Rotation or Drag resistance - fr

Frictional resistance caused by belt scuffing over forward tilted, skew and misaligned idlers - ft

Total friction factor f = fi + fm + fr + ft

This friction factor is calculated for each individual conveyor Section, allowing you to alter idler spacing of individual sections in order to optimize power consumption.

There are many other secondary resistances such as Belt Scrapers, Skirts, Material Acceleration etc. but these are covered in the normal conveyor calculations by the program and so are not considered as part of the friction factor.

Proportion of Friction factor

Typical breakdown of fProportion of friction factor for long horizontal conveyors

60%25%

9% 6%

Rubber IndentationMaterial & Belt FlexureIdler Rim DragIdler Misalignment

Indentation Resistance - Belt on Idler

Indentation Resistance

This resistance is caused by the idler roll pressing into the relatively soft belt cover rubber. It is intuitively apparent that the more the penetration of the idler roll into the belt cover, the more resistance there is likely to be. Many people have researched this subject and names such as Jonkers, Spaans, Hager, Maton, Lodewijks and Wheeler come to mind. . See References

From this research it is evident that the main factors which affect the indentation resistance are the actual rubber properties of the belt cover, the diameter of the idler rolls and the load on the idler roll, which for a fixed tonnage and belt speed is dependent on the idler spacing.

Jonkers developed the following formula for the Indentation resistance

( ) ( )343

1

2'' 14.1 rr

rer Bq

BDEZdeltaTanF ⎟⎟

⎠

⎞⎜⎜⎝

⎛=

Where F' is the Indentation resistance

Z is the belt rubber cover thickness

E' is the Dynamic Modulus of the rubber cover in N/mm2

Tan(delta) is the Loss Factor Tan(delta) property of the rubber cover

D is the idler roll diameter

Br is the idler face width

Qr is the load on the idler

This Resistance is calculated for centre and wing roll idlers and summed to get the total indentation resistance for the conveyor section under consideration, and then the friction factor fi for indentation is obtained by the program.

The parameters E' and Tan(delta) for the belt rubber cover properties are obtained by a laboratory test procedure called Dynamic Mechanical Analysis, usually performed by the Belt manufacturer or specialist laboratories. There is DIN standard number 53513 which covers the procedure for obtaining these values and they are normally in the following ranges

E ' = 4 to 35 Mpa

Tan(delta) = 0.1 to 0.6

These values are dependent on the temperature of the rubber as well as the rate of deformation (in radians per second or Hz) of the rubber cover, which in turn is related to belt speed, idler roll diameter and idler spacing. The deformation rate is calculated by the Helix delta-T program and it is shown on the Viscoelastic Friction Factor report. It normally ranges from about 300 rad/s up to 3000 rad/s.

Dynamic Mechanical Analysis - Sample Data for 4 types of rubber.

Rubber Sample 1

Rubber DMA Properties - Low Resistance Rubber 1 at 10Hz

0

10

20

30

40

-50 -30 -10 10 30 50

Temperature, deg C

Dyn

amic

Mod

ulus

E'

N/m

m2

00.10.20.30.40.50.60.70.8

Tan(

delta

)

E' Tan(delta)

Temp deg C E' Tan(delta)

-50 35 0.7

-40 18 0.55

-30 8 0.4

-20 6 0.25

-10 5.5 0.19

0 5.2 0.16

10 4.85 0.14

20 4.64 0.13

30 4.5 0.11

40 4.4 0.1

50 4.3 0.09

Rubber Sample 2


0

10

20

30

-50 -30 -10 10 30 50

Temperature, deg C

Dyn

amic

Mod

ulus

E'

N/m

m2

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Tan(

delta

)

E' Tan(delta)


-30 27 0.58

-20 14 0.38

-10 10 0.25

0 9 0.192

10 8.2 0.17

20 7.5 0.144

30 7.2 0.132

40 6.95 0.118

50 6.5 0.108

Rubber Sample 3


0

10

20

30

40

-50 -30 -10 10 30 50Temperature, deg C

Dyn

amic

Mod

ulus

E'

N/m

m2

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Tan(

delta

)

E' Tan(delta)


-30 37 0.58

-20 17.5 0.38

-10 11.4 0.25

0 9 0.192

10 8.2 0.17

20 7.2 0.144

30 6.3 0.132

40 5.95 0.118

50 5.85 0.108

Rubber Sample 4


0

10

-50 -30 -10 10 30 50

Temperature, deg C

Dyn

amic

M

odul

us E

' N

/mm

2

00.050.10.150.20.250.30.35

Tan(

delta

)

E' Tan(delta)


-30 7.3 0.306

-20 6.2 0.21

-10 5.5 0.17

0 5 0.152

10 4.6 0.147

20 4.3 0.142

30 4 0.139

40 3.7 0.135

50 3.45 0.128

The curves and tables above show typical values of Low Resistance rubber Dynamic Mechanical Analysis showing E' and tan(delta) values. Rubber properties can vary widely and it is important for users to obtain data from their own suppliers, or obtain independent laboratory analysis of the rubber.

The curves above are from tests carried out at a deformation frequency of 10Hz. The values will increase as the deformation frequency increases, and for a frequency of 1000Hz, the values may be about 10 percent higher than shown here. The increase in E' and Tan(delta) due to frequency increase may be estimated as 10 percent per decade on a log scale. i.e. 10% for a jump from 1 Hz to 100 Hz, a further 10% for a jump from 100 Hz to 1000Hz etc. Refer to [10] "Physical Testing of Rubber by R.P Brown, page 149. See References

The user must ensure that the input values for the E' and Tan(delta) are applicable to both the temperature and the deformation rate. There are methods, namely Williams Landel Ferry (WLF) and Arrenhius for adjusting the E' and Tan(delta) values - refer to references for details.

At different temperatures and frequencies, the rubber properties can vary over a wide range and it is important to use the applicable E' and Tan(delta) values for your operating conditions. It is also worth noting that the deformation of the rubber increases the rubber temperature due to hysteresis, and this in turn reduces the E' and Tan(delta) values, however, a decrease in Tan(delta) reduces the indentation resistance proportionally whilst a reduction in E' increases the resistance by the power of 1/3.

Some texts indicate that for most rubbers at room temperature, the E' and Tan(delta) values reduce by 1% for every 1 degree C increase in temperature, and that the E' and Tan(delta) values increase by 10% for every decade increase in the deformation frequency. E' and Tan(delta) values should not be extrapolated linearly, as the rubber can pass through a transition zone where large variations in E' can have a big effect on the Tan(delta) values as well. Care must be taken to ensure that the values used in the program have been estimated from the so called 'Master Curve' for the rubber using appropriate WLF shift factors.

Certain rubbers may contain a large proportion of filler such as carbon black, and this changes the properties of the rubber, possibly even reducing the amount of indentation due to the added 'stiffness' of the rubber due to the filler, but also increasing the loss factor Tan(delta).

Factors which affect the Indentation rolling resistanceThe following factors indicate the sensitivity of the indentation rolling resistance. For example, if you alter input data by a factor of 2, the following influence on the indentation resistance factor fi will result:

Vertical load on the belt is factored exponentially to a power of 2^4/3 = 2.52

Diameter of Idler rolls is factored 2^2/3 = 1.58

Viscoelastic Property E' is factored as 0.5^1/3 = 0.79

Viscoelastic property Tan(delta) is directly proportional i.e factor is 2 times.

Belt Cover thickness is factored 2^1/3 = 1.26

Belt Speed increases the deformation frequency and E' and Tan(delta) increase marginally as the frequency increases, so belt speed increase will generally increase indentation rolling resistance. The user must ensure that the E' and Tan(delta) values used in the input data are applicable at the actual deformation frequency calculated and shown on the calculation reports. However, belt speed decreases the vertical load, which has a significant effect as seen from the factor above.

Idler Spacing - closer idler spacing reduces the load on the individual rolls, but increases the number of idlers in turn increasing the rim drag and skew and tilt resistance. It also has a marked effect on belt sag, which in turn affects the material and belt flexure resistance which is very sensitive to changes in belt sag.

Belt Condition - worn belt

It is worth noting that the friction factor can reduce significantly with a worn belt. If measurements on power consumption are being made on existing conveyors, it is important to record the actual belt mass and cover thicknesses of the worn belt and to use this mass for the calculations.

Design Optimisation and Sensitivity AnalysisThe Helix delta-T program combines all of the factors affecting the power calculations so that the user can quickly perform a sensitivity analysis to determine the optimum configuration by trial and observation.

Even if you do not have exact figures for the belt rubber tan(delta) properties, or the idler rim drag, or the misalignment of the idlers, you can still optimize your design. Change the idler spacing, note the effect on friction factor, change belt speed, change the idler roll diameters, note the effect, change rim drag, note effects etc.

Belt and Material Flexure

Belt and Material Flexure ResistanceThis resistance can be described as the resistance caused by the bending and flexing of the belt over and between each idler roll along with the flexure of the material over each idler roll. It is apparent that if you had a perfectly flat belt which did not sag at all between idlers, then there would be no flexure resistance. This implies that the flexure resistance is proportional to the belt sag between idlers.

The Helix delta-T program uses a method developed by Ozster, Behrens and Vincent (See References) and it depends on the amount of belt sag, which in turn depends on load per m, idler spacing and belt tension. Now belt tension depends on takeup mass and also on belt sag, so an iterative process is required in order to determine the belt sag vs belt tension equilibrium values, and hence the Flexure resistance.

According to Behrens, the flexure resistance friction factor is given by the following:

( )m

ave

nmb

TWW

ccfm+

= 54

Where C4 is a function of the troughing angle

C5 a function of number of idler rolls and configuration .i.e. 3 or 4 or 5 roll idlers

m is an exponent function of the troughing angle (0.76 for 45 deg, 0.83 for 35 deg)

n is an exponent function of the troughing angle (2.06 for 35 deg and 2.26 for 45 deg)

T is the belt tension in kgf

The delta-T program shows the Flexure friction factor fm calculated in the Viscoelastic friction factor report, as well as the percentage this makes up of the total friction factor.

According to Wheeler, the material flexure resistance is proportional to the kinematic internal friction angle of the bulk material - see [10] in References

Adjustment factor for FlexureIn the Helix delta-T software, rather than having an input value for the internal co-efficient of friction for the material, we have provided an adjustment factor for the material flexure fm. This adjustment factor allows the user to adjust the fm values according to the material properties.

Length of Conveyor SectionBecause the friction factor due to material and belt flexure varies with the amount of belt sag, and in turn belt sag is dependent on belt tension, it is important to try to balance the lengths of individual sections of conveyor. You should avoid having exceptionally long sections of conveyor in the model, as the friction is calculated based on the average belt tension over the section of conveyor. Having very long or unbalanced length sections can allocate more or less weight to the section in the form of a high or low friction factor than it deserves.

Idler Rolling Resistance

Idler Rotation resistanceThe idler rolls have a rolling resistance due to seal drag and bearing rolling friction. Once again, many experiments, research and papers have been published on this subject. Bearing friction formulae are also published in bearing manufacturers catalogues - refer to SKF and FAG catalogues for more details.

Seal drag and effects of viscosity of the lubricant are more difficult to quantify as these can vary not only due to manufacturing variations but also due to site conditions such as temperature, ingression of dust, age of installation etc. For this reason, the Helix delta-T program uses a simple input for the rolling resistance and this is the actual resistance per roll. The resistance per roll is usually in the range of between 1N to 4N per roll.

Some idler manufacturers have published measured data and we reproduce data from Sandvik Materials Handling (Prok Idlers) below as a guide. Actual rolling resistance may be substantially different due to site conditions - consult your supplier.

Rolling Resistance for Prok Idlers

Idler Series Roll Diameter, mm

Rim Drag, per Roll, N

10 102 1.55

11 114 1.53

12 127 1.50

05 114 1.60

15 127 1.58

20 152 1.55

22 127 2.10

23 152 1.90

25 127 2.40

30 152 2.35

32 178 2.25

35 152 2.60

40 178 2.50

45 152 3.20

50 178 3.00

54 152 3.50

59 178 3.30

59(impact) 178 3.00

55 152 3.90

60 178 3.80

65 194 3.70

*Above figures are on the conservative side

Figures above are tested at 4 m/s belt speed and after 2 hours running with Shell Albania grease. Prok are constantly striving to improve designs and reduce the roll drag - we recommend that you obtain the latest data from your supplier.

In some cases the actual rolling resistance can be significantly lower due to the idlers becoming "run-in". This is due to smoothing of the bearings, freeing up of the labyrinth seals, bedding in of the lip seals, and reduction in grease viscosity due to temperature rise. It is known that for 152mm 3 roll idlers this rolling resistance has reduced to 1.18N per roll on carry idlers and 1.2 N per roll on vee return idlers.

More information can be obtained from the South African bureaux of Standards SABS 1313 - 1: 2002 and also SABS 1313 - 1: 1998 and DIN standard.

Idler Skew and Tilt misalignment

Idler Skew and Forward TiltIf the idler rolls are not aligned perpendicular to the belt travel direction, a scuffing resistance results. The magnitude of this scuffing resistance depends on the amount of misalignment as well as the co-efficient of friction between the belt and idler roll. The co-efficient of friction will in turn depend on whether the belt surface is dry, wet or moist.

The inputs are the amount of Skew angle in degrees, which is the misalignment in a plan view of the conveyor and also the amount of forward tilt angle in degrees for wing rollers. The user can adjust the amount of Skew and Tilt angle to suit the average misalignment of the idlers in the installation.

The scuffing resistance is calculated from the load on each conveyor roll using the co-efficient of friction between belt and idler roll of u = 0.35.

Scuffing Resistance θμmgSinR =

Where u = 0.35 is co-efficient of friction

mg is down-force on roll in N

theta is skew angle in degrees.

Where the conveyor has inclined side roll idlers such as normal 3 roll idlers and you input both a skew and a forward tilt angle, the angle theta in the resistance calculations is taken as the square root of the sum of the squares of the individual angles.

22 βαθ +=

Where alpha is the Skew angle and beta is the Forward Tilt angle.

Viscoelastic friction factor - References

Ref Paper Title Authors Publication

1 The Indentation Rolling Resistance of Belt Conveyors

C.O Jonkers Fordern und heben vol.30 (1980) No 4

2 Large Capacity Belt Conveyors - Motion Resistance Evaluation

Z.F. Oszter, W.k.Behrends, D.Vincent

Mining Engineering, December 1980

3 The Effects of Idler Alignment and Belt Properties on Conveyor Belt Power Consumption

A.E. Maton Bulk Solids Handling Vol 11 No 4 January 1991

4 The Development of Low Friction Belt Conveyors for Overland Applications

D.E Beckley Bulk Solids Handling Vol 11 No 4 January 1991

5 The Rolling Resistance of Conveyor Belts

G. Lodewijks Bulk Solids Handling Vol 15 No 1 January 1995

6 Viscoelastic Properties of Polymers John D Ferry University of Wisconsin

7 Physical Testing of Rubber R.P. Brown Technical Manager RAPRA Technology Ltd, U.K

8 Properties of Polymers D.W. van Krevelen, P.J Hoftyzer

Elsevier Scientific Publishing Co, Amsterdam

9 The Calculation of the Main Resistances of Belt Conveyors

C. Spaans Bulk Solids Handling Vol 11 No 4 November 1991

10 Bulk Solid Flexure Resistance Craig A Wheeler Bulk Solids Handling Vol 25 (2004) No 4

11 Calculating Flexure Resistance of Bulk Solids Transported on Belt Conveyors

Craig A. Wheeler, Alan W. Roberts, Mark G. Jones

Particle Systems Characterisation 21 (2004)

12 Application of Time Temperature Superposition Principles to DMA

TA Instruments www.tainst.com

13 Application of Time Temperature Superposition Principles to Rheology

TA Instruments www.tainst.com

14 Viscoelasticity and dynamic mechanical testing - AN004

A. Franck, TA Instruments Germany

www.tainst.com

15 The Power of Rubber - Part 1 L.K Nordell Bulk Solids Handling Vol 16 No 3 November 1993

16 The Energy Saving Design of Belts for Long Conveyor Systems

M. Hager and A Hintz Bulk Solids Handling Vol 13 No 4 November 1993

17 Theory and Practice of Engineering with Rubber

P.K. Freakley and A.R Payne

Applied Science Publishers Ltd, London

18 Overland Conveyors Designed for L.K Nordell Bulk Solids Handling Vol 26 (2006)

Efficient Cost and Performance No 1

19 DIN 53513 - Determination of the viscoelastic properties of elastomers on exposure to forced vibration at non-resonant frequencies

Deutche Industrial Norm

DIN 53513

http://webstore.ansi.org/ansidocstore/

20 Indentation Rolling Resistance of Belt Conveyors - A Finite Element Solution

Craig A Wheeler Bulk Solids Handling Vol 26 (2006) No 1

21 Elastomers, Collected Applications of Thermal Analysis

Mettler Toledo, GmbH http://us.mt.com/mt/products

22 Investigation on Causes and Value of the Indentation Rolling Resistance of Belt Conveyors

M. Hager, L. Overmeyer and F. Scholl

Bulk Solids Handling Vol 25 (2005) No 2

23 Theoretical basis industrial applications of energy-saving and increased durability of belt conveyors

Jerry Antoniak Acta Montanistica Slovaca Rocnik * (2003) Eislo 2-3

24 Mechanical Properties of Solid Polymers, 2nd edition

I.M Ward John Wiley & Sons

Acknowledgement

Helix Technologies wishes to acknowledge, with gratitude, the valuable assistance provided by Mr. A. E. Maton in the development of the Viscoelastic calculations, including passing on his considerable knowledge in this field, as well as for testing and verification of the software against known conveyor installations.

Viscoelastic friction factor - Belt Properties Inputs

The following form shows the Viscoelastic belt properties input form.

The first tab sheet is for the belt properties.

Enter Description for the belt rubber - this is for record purposes.

Enter the Dynamic Modulus E' for the top cover of the belt. This value should be adjusted for the expected operating temperature of the belt cover as well as the calculated deformation frequency which will be realized (refer Viscoelastic Friction Factor Report for the calculated frequency), remembering that running the conveyor raises the temperature, however, at low temperatures, the E' value is usually higher. A higher E' values results in a lower indentation resistance. Also, at higher frequencies, the E' value usually increases.

Enter the Loss Factor Tan(delta) for the top cover. Again this must be for the temperature and frequency for the calculation case. Refer to the Viscoelastic friction - Indentation help topic.

Repeat above for the belt bottom cover rubber.

If the conveyor has a belt turnover on the return belt run which turns the belt over after the takeup or head end so that the clean side of the belt is in contact with return rollers (same side as in contact with carry rollers), then click the Conveyor has belt turnover on return run button to ON. This ensures that the bottom cover rubber properties are also used for the return belt run.

Enter an adjustment factor for the Material and Belt flexure friction factor. The program uses the methods developed by Behrens for estimating the flexure resistance flexure resistance. This paper was based on Iron Ore conveyors, and so if your application has an appreciably lower or higher material flexure resistance, you can adjust the values up or down. Wheeler [10, 11] has published research into the effects of the Internal Co-efficient of Friction of the material on this flexure resistance.

Viscoelastic friction factor - Idler Inputs

The Idler Roller Details tab sheet requires the inputs relevant to the Viscoelastic Calculations which are not already captured by the program elsewhere, such as in the idler input forms.

These inputs allow you to input different Roll Diameters and roll length for centre and Wing Rollers. For example, increasing the centre roller to the next size up may have a significant reduction in indentation rolling resistance

Enter the Centre Roll Diameter in mm for the Carry Side - the current selected idler diameter is shown in grey.

Enter the Wing Roll Diameter in mm for the Carry Side - the current selected idler diameter is shown in grey.

Enter the Centre Roll Rim Drag in N per Roll. His value is multiplied by the number of rollers to get the total resistance per idler set.

Repeat inputs for Wing Rollers and also for Return Idlers.

For Vee type 2 roll carry or return idlers, enter the Idler Roll data in the Centre Roll input section. Data in the Wing roll sections will be ignored. For 4 roll idlers, the two centre roller data is taken from the Centre Roll inputs and the two outer roller data is from the Wing Roll inputs. 5 roll idlers are one Centre roll and 4 wing rollers.

Now input the Idler Set Skew Angle and Forward Tilt angle. See Idler Skew and Tilt for details of the angles and nomenclature.

Dynamic Analysis - Introduction

New Dynamic Analysis moduleA new version of the program which has full Dynamic Analysis capabilities has been added to the existing Lite, Standard and Professional versions of the software.

This new version calculates the transient belt Tensions and Velocities during starting and stopping of a conveyor. It can model the conveyor belt transient behaviour during Starting Fully Loaded, Starting Empty, Stopping Fully Loaded and Stopping Empty. The program allows the user to input any number of Drives or Brakes and allows for input of Drive Torque / Speed curves, Delay times, Braking Torques, Flywheels and inertia effects. After the Dynamic Calculations have been performed, the user can view and Print two dimensional and surface plot three dimensional graphs for Belt Tensions, Belt Velocities, Strain rates and Takeup movement versus time step for all points along the conveyor.

The Dynamic calculation process uses sophisticated Variable Step Runge Kutta method integrators for solving the complex differential equations. All the numerical analysis is compiled into the program and it does not require any other software to perform the calculations or display graphs etc. It also allows flexible, easy to use boundary condition specification by the user.

The Dynamic Calculations are easy use to use and Engineers who have static conveyor design experience can perform these complex dynamic simulations using this very powerful software.

• Easily model the belt transient tensions and velocities during Starting and Stopping of conveyors.

• Add Torque Control or Speed Control on drive acceleration.

• Add Delay times for multiple drives for Dynamic Tuning

• Add Flywheels to pulleys to optimise starting and stopping

• Add Brakes to pulleys as required.

• View the movement of the Takeup pulley during Starting and Stopping

• Predict the maximum Transient Belt Tensions at any point along the conveyor as well as the timing of these transients.

• Compare the Dynamic Calculations results with the rigid body static calculations in the delta-T5.

• Predict the magnitude of transient loads on conveyor structures.

• Calculate the torque loadings on gearboxes and couplings during starting and stopping. Eliminate conditions which may cause costly equipment failures.

• Perform Dynamic Tuning by changing the start delay times on different drives

Belt Velocities during Starting Fully Loaded

Movement during Starting

Drive Starting Torques Curve for Wound Rotor Motors

Dynamic Analysis - Overview

Helix delta-T uses a Finite Element model of the conveyor to perform the dynamic analysis. The conveyor is broken up into segments, and for each segment, we use a Kelvin solid model, which is a spring in parallel with a viscoelastic element, as shown below:

Kelvin Solid Model

Conveyor Model DiagramThe conveyor model created and captured in the normal delta-T program is automatically broken up into segments in the Dynamic Calculation process. The program already knows the geometry of each section of conveyor, as well as the idler spacing, rotating masses, resistances, inertias, drive power and location, takeup mass and the equivalent mass of each element in the conveyor. The Dynamic calculation breaks the standard conveyor sections into smaller segments. The designer can specify the maximum segment length to be used.

( ) ( ) ( ) miiiii FtWgmtTtTVm +−−−= + θsin1

.

Delta-T uses the Finite Element method of dynamic analysis.

Once the conveyor is segmented, the moving mass, length etc. of each segment is known. The Tension force acting on segment i at time t is given by the sum of the spring and viscoelastic Tension forces, Ts and Tv respectively. At each time step of say 0.1 seconds, the rate of change of velocity, combined with the strain on each conveyor segment is calculated. The peripheral force at the drive pulleys is the motivating force. The main conveyor resistances, represented by the Coulomb friction factor f, which is a function of instantaneous belt tension and belt sag at the segment under consideration, are taken into account. All idler roller rotating masses and pulley, drive and brake inertias are included in the acceleration and tension calculations. The Drive Torque or Velocity is input graphically, and the resulting Belt Tensions, strains and belt Velocities are output for each time step and for each point along the conveyor. These values are presented graphically for ease of interpretation.

Sample of 3D surface plot Belt Tensions of a conveyor stopping

A typical conveyor Dynamic Analysis run of say 60 seconds may include 60,000 individual Tension (or Velocity, Strain) values and the best way to present these values is graphically. Delta-T allows you to view a two dimensional graph of (say) Tension vs Time for any point along the conveyor.

Belt Tensions during Starting Fully LoadedIn the sample graphs only a few conveyor stations such as Tail, Head, Drive, Takeup have been plotted for clarity. You can plot any station's values merely by clicking on the label and pressing a button.

For more details about the Theory of Conveyor Dynamics refer to the list of References.

Dynamic Analysis - Drive Torque Speed Principles

Helix delta-T allows the designer to control the starting of a conveyor by means of

• Torque Control

• Speed Control

Torque ControlTorque control means that the Torque, expressed as a % of Full Load Torque is the controlled parameter at the Drive. This means that the Driving Peripheral force on the drive pulley is controlled and the magnitude of the force depends on the actual pulley speed at each time step expressed as a % of Full Load Speed.

Typical Starting Torque Curve for an Induction motor

Load Torque

Starting Torque

Pull-up Torque

Pull-out Torque

Negative Torque - braking

AcceleratingTorque

Typical Induction Motor starting Curve input into Delta-T program

The delta-T program allows you to model each Drive's Starting Torque vs Speed characteristics. The method used is a tabular description of the % of Full Load Torque vs the % of Full load speed. All you need to do is enter the Torque % at the relevant % Speed values and the program will draw the curves for you and then use regression methods to get the actual values of Torque to apply during the calculation process.

The Full Load Speed and Torque and is reached when 100% Speed is reached. Note that if the conveyor tries to run at speeds above the Full load speed of the motor, the available torque from the drive drops off rapidly, and the Conveyor load will then tend to bring to reduce the speed. Above the asynchronous speed the torque is reversed ie it becomes negative and the motor acts as brake.

This overspeed braking effect is very important in Conveyor operation and Dynamic Analysis, as it helps to control the drive speed and keep it from overspeeding. For regenerative conveyors, the motor operates in the band above the 100% FL speed range and thus acts as a brake.

Load Torque vs Drive TorqueDuring the Dynamic Analysis calculations, the Torque supplied by the drive is applied to the drive pulley. When the Drive starts, the Starting Torque is applied and as the drive pulley accelerates, the Torque % along the curve is progressively applied until the pulley reaches 100% of Full Load speed. If the drive pulley is pushed over the full load speed by a Tension wave, the Torque reduces to below the Load Torque and the drive slows down. Eventually equilibrium is reached where the Drive Torque equals the Load Torque.

Load Sharing between DrivesThe above equilibrium explains why Squirrel Cage electric motors automatically load share. If one Drive takes less than its fair share of load, the other drives takes more share. This causes the second drive to slow down, and as it slows down, the first drive will automatically take more load.

Wound Rotor or Slip Ring MotorSlip ring motors or wound rotor motors are a variation on the standard cage induction motors. The slip ring motor has a set of windings on the rotor which are not short circuited, but are terminated to a set of slip rings for connection to external resistors and contactors. The slip ring motor enables the starting characteristics of the motor to be totally controlled and modified to suit the load. As the motor accelerates, the value of the resistance can be reduced altering the start torque curve in a manner

such that the maximum torque is gradually moved towards synchronous speed. This results in a step controlled starting torque from zero speed to full speed at a relatively low starting current. The sliprings and brush assemblies need regular maintenance which is a cost not applicable to the standard cage motor.

Resistors are switched to control Startingtorque between 150% and 110% in this case

Wound Rotor Motor Speed Torque Curve Input into Delta-T

Delta-T applies the calculated torque at each time step to the Drive pulley according to the relationship shown in the Torque speed Curve. This means that the program can model any Torque Speed relationship you wish.

Fluid Coupling Torque ControlA Fluid Coupling is a device consisting of an impeller and a runner where the impeller is driven by the motor and torque is transmitted to the runner by fluid between the impeller and runner. This allows the motor to start freely and as fluid is drawn into the impeller / runner interface, the torque on the output shaft of the fluid coupling increase gradually until it is sufficient to move the conveyor and accelerate it. To use a Fluid Coupling Start in Helix delta-T, merely enter the output shaft Torque Speed curve for the fluid coupling as a mapped dataset in the Torque Speed curve table. The program will then use whatever shape of curve you specify.

Cross sectional drawing of a soft start fluid coupling and some typical Torque speed curves - Drawing and Graphs Courtesy Voith Transmissions.

Speed ControlThe second method of starting control is known as Speed Control or a Velocity Ramp control. This method of control does not specify the amount of Torque applied to the Drive pulley. It specifies a pulley Speed at each time step during acceleration and sufficient Torque is applied in order to maintain the specified speed. This method of starting is usually provided by electronic solid state Variable Speed Drives which control the motor speed accurately to with fractions of a percent of Full Load Speed.

A typical linear Velocity Ramp

In the above starting speed ramp the speed increases linearly with time.

S curve Acceleration RampsNotably A. Harrison and L. Nordell have proposed various 'S' curve acceleration ramps. Both of these starting methods can be simulated in delta-T. Refer to the papers on these subjects in the References section for more details.

S curve - Harrison ModelThis form of S curve was first proposed by Dr Alex Harrison and it is called a cycloidal front characteristic.

CycloFront S Curve (Harrison)

The cycloidal front curve is derived from

( ) TttT

CosVtv ≤≤⎟⎠⎞

⎜⎝⎛ −= 0,1

2π

The maximum acceleration is a = V/2 when t = T/2

S curve - Nordell ModelThis form of S curve was first proposed by Nordell. It takes the form

S Curve (Nordell)

This S curve is obtained as follows:

( )2

0,22

2 TtTtVtv ≤≤⎟⎟⎠

⎞⎜⎜⎝

⎛=

( ) TtTTt

TtVtv ≤≤⎟⎟

⎠

⎞⎜⎜⎝

⎛−+−=

2,241 2

2

Nordell's model has a higher acceleration than Harrison's but a lower Jerk (first derivative of acceleration)

In delta-T, you are free to use any Velocity ramp you wish - merely type in the speed time values and the program will do the rest. You can also derive your own relationships using a spreadsheet program such as Excel and then paste the values into delta-T.

Dwell Period Velocity RampAnother popular starting velocity ramp has a built in dwell period during which the velocity is kept constant. This is intended to allow the whole belt to be tensioned by the drive and to start moving, before acceleration is resumed.

Dwell period

Dwell Period Velocity Ramp

Aborted StartYou can model an aborted start by truncating the Drive Torque vs Speed curve. For example, if the start is aborted at 80% of Full load Speed the following (simplified) Torque speed curve could be used to model the conveyor.

Torque Speed Curves for Drive No 1

Speed, % of Full Load Speed10095908580757065605550454035302520151050

Torq

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Aborted Start Torque Speed Curve

With the above curve, the drive will accelerate and settle at a speed equal to 80% of the Full Load Speed of the conveyor. By observing the time it takes to reach this 80% speed (from the Belt Velocities graph), you can see what the belt tensions would be at that stage.

Dynamic Analysis - Torque Speed Input

You can setup the Torque vs Speed relationship for a Drive under starting conditions. From the main Dynamic Data Input form select the Drive Starting Torque Input tabsheet. The following form will be displayed:

This form allows you to type in the relationship between Drive Torque vs run-up speed; both expressed as a percentage of Full Load Torque and Full Load Speed. We use % value rather than absolute values because this allows us to change the actual kW of a drive without having to re-input all the values. So once you have modelled (say) a Direct on Line Induction motor start you do not need to re-model it for all motor sizes, provided that the shape of the curve is applicable for the size of drive you are currently modelling.

Overview of torque speed data table structure:All the drive data is stored in a single table. It is sorted according to MapDatasetNo field. Some Datasets will apply to Torque vs Speed curves and some to Speed vs Time curves. If you are on

the Torque - Speed tabsheet and you select a MapDatasetno which contains Torque speed data, then it will be displayed in the graph. However, if the selected MapDatasetno contains Time vs Speed data you will get only a straight line displayed. Click on the Speed Time tabsheet and you will see the data, or enter new MapDatasetNo until a Torque vs Speed dataset appears.

All the drive data is stored in a single table. It is sorted according to MapDatasetNo field. So to add a new set of data, merely give it a new unused MapDataset number and then add the data. Later, when you do the dynamic calculations, you can point the Drive to any MapDatasetNo and the program will use the current data for the calculations. This makes it easy to compare different starting methods in the same design file.

Link between Drive No and MapDatasetno

• First Select the Drive No using the data control to left of the Drive Number edit box• Select the Dataset no to display in the curve. This action filters out all other data except the

number selected and redraws the curve based on the data in the Speed% and Torque% columns.

• To add a new drive Starting Torque curve, just type in a new unused MapDatasetNo and then add new rows in the table using the new Mapdatasetno.

For example:

Type 15 (say) in the yellow MapDataset no box. The program will now filter the data table and display only records with 15 as the MapDataset field value. If no records exist with 15, then a blank table and graph will be displayed:

Blank table and graph for newdataset no 15 (say)

Now type in the table - • Start by adding 15 in the MapDatasetno column. • Then put in a description for the Drive. Eg DOL Motor or Wound Rotor. • Type in the Full Load Torque and Full Load Speed for this drive. These are for information only.• Now type in a Speed % of 0.01 to start with• Type in the Starting Torque % at 0.01% speed - say 220% for an Induction motor• Now add a new row by using the Datacontrol + button or by using the Down Arrow on your

keyboard.• Add the next Speed% and Torque% values• Add new rows as required. It is only necessary to add the MapDatasetNo, Speed% and Torque%

values in each row.• Press the Draw Curve button or the enter button to view the Graph• When all the data is entered you can proceed to the Drive Start & Brake Delay Times tabsheet.

For multiple drive conveyors, select the Next Drive number using the Datacontrol button and then type in the Map to Torque Dataset No to set up the details for the second drive. Repeat this for all drives.Each drive can be mapped to a different MapDatasetNo or to the same one if it is identical.

Print Report

You can print a record of the Torque vs Speed values for each drive by using the Reports, Drive Speed Torque Curve main menu.

Example of Wound Rotor motor speed torque curve report.

Dynamic Analysis - Speed Time Velocity Ramp

You can setup the Velocity Ramp vs Time relationship for a Drive under starting conditions. From the main Dynamic Data Input form select the Drive Starting Speed Ramp Input tabsheet. The following form will be displayed:

This form allows you to type in the relationship between Drive Speed vs run-up Time in seconds.

Overview of speed - time data table structure:All the drive data is stored in a single table. It is sorted according to MapDatasetNo field. Some Datasets will apply to Torque vs Speed curves and some to Speed vs Time curves. If you are on the Time - Speed tabsheet and you select a MapDatasetno which contains Time speed data, then it will be displayed in the graph. However, if the selected MapDatasetno contains Torque vs Speed data you will get only a straight line displayed. Click on the Torque speed tabsheet and you will see the data, or enter new MapDatasetNo until a Speed vs Time dataset appears.

To add a new set of data, merely give it a new unused MapDataset number and then add the data. Later, when you do the dynamic calculations, you can point the Drive to any MapDatasetNo and the program will use the current data for the calculations. This makes it easy to compare different starting methods in the same design file.

Link between Drive No and MapDatasetno

• First Select the Drive No using the data control to left of the Drive Number edit box• Select the Dataset no to display in the curve. This action filters out all other data except the

number selected and redraws the curve based on the data in the Time and Speed% columns.• To add a new drive Starting Speed Ramp curve, just type in a new unused MapDatasetNo and

then add new rows in the table using the new Mapdatasetno.

For example:

Type 15 (say) in the yellow MapDataset no box. The program will now filter the data table and display only records with 15 as the MapDataset field value. If no records exist with 15, then a blank table and graph will be displayed:

Blank table and graph for newdataset no 16 (say)

Now type in the table - • Start by adding 16 in the MapDatasetno column. • Then put in a description for the Drive. Eg S curve Ramp. • Type in the Full Load Torque and Full Load Speed for this drive. These are for information only.• Now Type in the Time in seconds, starting with 0.01as the first value• Type in the Speed % at 0.01 time - say 0% for a VSD drive• Now add a new row by using the Datacontrol + button or by using the Down Arrow on your

keyboard.• Add the next Speed% and Time values• Add new rows as required. It is only necessary to add the MapDatasetNo, Speed% and Time

values in each row.• Press the Draw Curve button or the enter button to view the Graph

• When all the data is entered you can proceed to the Drive Start & Brake Delay Times tabsheet.

For multiple drive conveyors, select the Next Drive number using the Datacontrol button and then type in the Map to Speed Dataset No to set up the details for the second drive. Repeat this for all drives.Each drive can be mapped to a different MapDatasetNo or to the same one if it is identical.

Print Report

You can print a record of the Time vs Speed values for each drive by using the Reports, Drive Speed Torque Curve main menu.

Example of Speed Time Velocity Ramp curve report.

Dynamic Analysis - Start & Stop Delay Times

The program allows you to specify a Delay time before a Drive is started or a Brake is activated. This allows you to perform fine-tuning of the design in order to minimise dynamic tensions in the system.

Select the Drive Start & Brake Delay Times tabsheet from the Dynamics Data Input form. The following will be displayed:

To add delay time to a drive:

• Select the Drive number using the Datacontrol

• Enter a Start delay time for this drive if modelling a Start sequence. You can enter a different Delay time for each drive. During the calculations, if the time step is less than this time, the drive is not actually activated and is in free-wheel mode. After this delay time is reached, the drive will start to follow the Torque% vs Speed% or Time vs Speed% you have mapped out for the drive.

• If you are modelling a stopping sequence, you can enter a delay time for the brake to be activated.

HoldBack Device.

On inclined conveyors, if they are modelled stopping with a full load, then there is a possibility that the conveyor will slow down and then actually start to run in reverse. The driving force here is gravity acting on the load on the belt. For an empty belt, the mass of the belt on the carry and return runs cancel each other out so runback is not normally an issue.

You can check if a conveyor needs a Holdback device by performing a Dynamic Calculation with the Conveyor Stopping fully loaded. Then in the dynamic Results form, click on the Draw Belt Velocities button and examine the graph of Belt Velocities. If the velocities at each point drop off to and then stabilise at zero, then the conveyor stops and does not run back.

However, if the velocities drop off and then continue to drop below the zero velocity line and continue

on with a downward trend, this indicates that the conveyor is running backwards. You will have to fit a Holdback device to the Drive or head pulley to prevent this runback.

Switch ON the Drive has holdback Device to prevent runback check box on the form. This will prevent the Drive pulley from attaining a negative velocity during the Dynamic Calculations. It will also increase the Belt Tensions at the Drive.

Only fit a Holdback to one drive.

Note that you should only have one drive with a holdback fitted. If you add a hold back to more than one drive, the Holdbacks will not necessarily share the load and so the tensions become unstable. Therefore, it is important to only switch on a holdback on one drive.

Backstop fitted - Drivepulley comes to stop andstays at zero velocity

Backstop increases belt tensions at drive during stopping.

Backstop increasesbelt tension at drive

Holdback Tension

No Backstop fitted - Drivepulley comes to stop andthen rotates backwards

Example of Holdback Tension graph - conveyor stopping fully loaded

Dynamic Analysis - Results Form

After performing the Dynamic calculations the Dynamic Results form will be displayed.

Click on the Draw Velocities button. A 2 dimensional graph showing the belt velocities will be drawn.

Note delay before tail pulley starts to move

Click here to select other points to draw

List of points drawn in graph - double click to delete one

Sample of Belt Velocities 2D Graph.

Note that the elements in the conveyor with names such as Tail, Head, Drive, Takeup are automatically added into the list of items to be graphed.

You can change the items graphed by clicking in the Drop down box at Top Right hand side of the form. All the pulley and intersection points in the conveyor will be listed, along with additional points created for the dynamic modelling. The additional points are sufficed with a /1, /2, /3 etc. To graph a

specific point along the conveyor, click on it in the drop down list and then press the Draw Velocities button again. The new point will be added into the graph.

To view the Belt Tensions click the Draw Tensions button.

Zoom in on Graph

To Zoom in click and drag downand to rightTo Zoom out click and drag upand to left

You can Zoom in on a section of graph - Left click with mouse and drag a rectangle down and to the right to zoom in - graph above is a zoomed section of the Belt Velocity graph above it.

To Zoom out, draw a rectangle by left clicking and dragging up and to the left with the mouse

Chart editor - change lines, colours, 3D, copyand print graph etc

Belt Tensions shown in 2-D format.

You can also view the graphs of the Belt Strain, the Takeup Travel and the Drive Starting Torque in 2-D format by clicking on the buttons.

Click on the 3D Graphs tabsheet to draw and view a Surface plot graph of Belt Tensions, Velocities etc.

of 3d Belt Tensions Graph with Transparency set to 25% in Chart Editor.

Use Toolbar to Zoom, Rotate, Copy or Edit chart.

To view and Print or Export a Graph you can use the Main Reports menu. Select View or Print 2D Graph report and the last displayed graph will be presented in a report which can be printed or exported in the normal way as for other Helix delta-T reports.

The same can be done with the 3D graphs.

To print a report of the Dynamic Input data, select Reports, Dynamic Calcs Input Data menu. A report showing the input data such as Belt Modulus, Damping Factors and Delay times will be shown - you can print or export this too.

Save Calculation Data

It is possible to save the calculated data by saving the Reports as QRP files. Because of the very large number of calculation results produced during the dynamic calculations, only the input data is saved to disk. If you exit the program and then want to return to view the results, you have to re-do the Dynamic Calculations. However, it is possible to save the Dynamic Result reports. View the report by selecting it from the Reports menu, then Export the report and save it as a .QRP (QuickReport) file. At a later stage you can view the report from any Report in Helix delta-T by opening a report (even in the standard section of program) and then clicking the Load Report button. Select the previously saved QRP file and it will be displayed.

Refer to the Export Reports help topic for details on the File formats you can save the reports as. Note that the Load Report only works with .QRP files.

You can also Export the actual Belt Tension and Velocity data by using the Chart Editor, Series, Data, Export menus. This data can then be saved a CSV for importation into Excel etc. Note that there are many thousands of points on each graph and this process can take a bit of time.

Dynamic Analysis - Fine Tuning

Dynamic Tuning is the process of optimising the performance of a conveyor during starting or stopping by changing Drive characteristics, braking torques, inertia's, belt strength (modulus), starting velocity ramps, delay times etc. As you can imagine, the combinations of which can be investigated is almost limitless. The challenge for the Helix delta-T user is to identify problem areas by examining the output results and then to eliminate these problems by changing the operating parameters or equipment selection in the conveyor.

A comparison of the Dynamic Results with the Static Tension graphs is always a good place to start. The conveyor belt should be able to operate satisfactorily when the 'Static' tension designs have been completed. An examination of the Dynamic Results will then highlight if there are any problem areas such as excessive sag or even negative belt tensions in the system. Also whether Tensions at drives or braking pulleys reduce to below the Minimum Required Tension to maintain Traction at all times.

Points to consider when examining Dynamic Results

• Maximum Belt Tensions - do they exceed the allowable tension rise above the operating tension of the belt? Affect on belt, splices, pulleys, shafts, and structures.

• Minimum Belt Tension for sag to prevent spillage of material

• Minimum Required Tension to maintain Traction at all times on drives and brakes - if the tension drops below the Minimum Required T2 tension, belt slip will occur. The program only applies Tension from drives and brakes to a pulley if there is sufficient T2 tension during the calculations.

• Tensions should stabilise at the same values shown in the Static calculations for running values. If not, investigate as there is probably an input error in the dynamics, such as a Torque speed Curve not equal to 100% FLTorque at 100% FL Speed.

• Takeup travel or movement - does the takeup move beyond the stops allowed for in the 'Static' design?

• Belt Velocities should stabilise at the Running belt speed during starting. If not, there is either too much torque available from the drive, or not enough to get it to speed and it 'stalls'

• Belt Velocities should go to zero when stopping. If they continue down and become negative, then a Holdback is required.

• Tension spikes. If your Dynamic Tension graph has large 'spikes' on it, this indicates numerical instability during the calculation process. You will need to increase the Delay Time Tau value in the dynamic input form and redo the calculations. Also, changing the maximum Element length of section will help to damp out the errors. The program uses the very best variable step size algorithms available for solving the differential equations, including an error checking and adjustment routine, but if you have a very stiff belt (high modulus) which is lightly loaded and so has low strain present, instability can result. Increase damping (delay time), increase element length or masses on each element and redo calculations

Numerical Instability - increasedelay time, increase elementlength, re-do calculations

• Observe the delay times before the Tail and other parts of the conveyor begin to move

Dynamic Analysis - Chart Editor

Editor

Chart Editor - use to edit colors, lines, 3D etc

Copy button

Introduction

The Chart Editor is designed to help you quickly modify Charts.

To get help on any Topic in the Chart Editor, select the button at the top right hand side of the Editor window and drag it onto the Topic in question. TeeChart Pro help will show you the runtime property or method associated with the feature.

Editor design

There are 2 principal sections to the Chart editor, Chart parameters and the Series parameters, which are separated as 2 tabs of the Chart Editor.

Chart pages

You may define overall Chart display parameters.

Series Pages

Series pages will contain parameters dependant on the series type concerned. The Combobox at the top of the Series tab page shows which series you are editing.

Export Dynamic Data results

You can also Export the actual Belt Tension and Velocity data by using the Chart Editor, Series, Data, Export menus. This data can then be saved a CSV for importation into Excel etc. Note that there are many thousands of points on each graph and this process can take a bit of time.

Dynamic Analysis Example- Level Conveyor

This conveyor is a 1200 wide ST1600 belt carrying 3500 tph of Iron over 2600m. It is fitted with 3 Drives, two x 315 kW on the Primary drive pulley and one x 315 kW on the Secondary Drive. It has brake fitted at the Tail.

Design Summary as follows:

This Conveyor is first modelled during Starting Fully Loaded. All the Drive motors are Wound Rotor motors switched between 150% and 110% of FL Torque as follows.

Dynamic Calculation Input Data is as follows

Drive reaches Full Load Speed

Tail Pulley starts moving after 3.5seconds - see Zoomed in Graph whichfollows

Conveyor Starting Fully Loaded Results - Belt Velocities

Note that the Drive reaches the design speed of 4 m/s after about 30 seconds - refer to green line on graph. The Static calculations predicted a starting time 30.02 secs, so this correlates well.

Zoom of Tail pulley Velocity

Tail Pulley starts moving after 3.5seconds - Zoomed from Graphabove

Rigid Body Starting timeDuration = 30.02 seconds

Belt Tensions starting Fully Loaded

Starting

Running

The Dynamic Tensions compared with the 'Static' Tensions from the normal delta-T calcs.

As can be seen from the Running Tensions above, the primary drive should be 258.77 kN. In the Dynamic Graph above, you can see the Red line for the Primary drive is about 258 kN at the end of the calculation run. The calc run was only done for 80 seconds, so the Standing waves have not been Damped out completely. Similarly the Secondary Drive, Takeup and Tail tensions at 80 seconds compare with the Static calculations.

Now let us look at the Starting Tensions from the Static calcs:

As you can see from the above bar graph, the Primary Drive Tension is 373.85 kN. When the Dynamic Graph above is examined, it shows the Primary Drive Tensions oscillating between 320kN and 420 kN, so the correlation is again good. The Dynamic calculations show that in fact the maximum belt tension is higher than the value shown in the rigid body calculations, but not by more than about 13%. However, the 13% peak could shorten equipment life and so may be significant.

A 3D Graph of the Belt Tensions is shown below:

Another view of the 3D Tensions

Graph of Takeup Travel

Average Starting

Average Running

The takeup Travel Graph shows the Takeup settling during running at about -0.85m from the original position when stationary, with a maximum travel of -2.3m. The normal Rigid body calculations show values of 0.97m Running and 1.78m Starting Full. This highlights that the Average Tension rise as used in the Rigid body calculations is less than the Peak Tensions which result in the Dynamic Calculations.

Dynamic Analysis Example- Level Conveyor Stopping

This conveyor is a 1200 wide ST1600 belt carrying 3500 tph of Iron over 2600m. It is fitted with 3 Drives, two x 315 kW on the Primary drive pulley and one x 315 kW on the Secondary Drive. It has brake fitted at the Tail. Refer to Help topic called Level Conveyor Starting for details of the Conveyor layout etc.

The following model shows the conveyor stopping with a fully loaded belt with the brakes applied. There are two brakes, one at the Secondary Drive is 20kNm brake torque on the pulley and the the other is at the Tail pulley and is a low speed brake equal to 50 kNm giving a total braking torque of 70 knm.

The Rigid body calculations indiacte a Stopping time of 10.59 seconds - refer to Report shown in previous section.

The Belt Velocity graph during stopping is shown below:

It can be seen from the Belt Velocity graph above that portions of the belt reach zero velocity at 9 seconds and then speed up again and the whole conveyor is stationary after 14 seconds. The blue line is the velocity at the loading hopper just after the Tail pulley.

Braking Tensions from Rigid body calculations

Dynamic Braking Tensions

Tensions at Hopper = Tightside of Tail brake pulley

Stationary Tensions

Slack side of Tail Brake

A comparison of the magnitude of the Dynamic Tensions on the tight side of the tail brake versus the Rigid body calculations show maximum values of 297 kN for Dynamic and 187 for static - this is a substantial difference. You can see how the Dynamic wave increases the tension at the brake from 110 kN up to the maximum of 297 kN.

3D Graph of Tensions during Stopping

Note the peak tension at the Hopper and the minimum Tension in the same Graph rotated for a better view below

The second 3D graph shows the minimum tensions occurring at the Intersection point before the Drive. When this Intersection point is graphed in the 2D graph it looks like the following:

Minimum Tension at Int. Ptbefore Primary Drive

The negative tension shown at the Intersection Point indicates material spillage would occur. Changes would have to be made to the design in order to prevent this.

The 3D Graphs help to identify the worst case because you can see the whole conveyor at once.

Dynamic Analysis Example- Inclined 3 Drive Conveyor

This conveyor is a large underground mine conveyor designed to lift ore up the main decline to the portal on surface. The basic conveyor is 2900m long with a lift of 501m. Capacity is 1000 tph and installed power is 3 x 630kW drives, 2 on the primary drive pulley and one on the secondary pulley.

Belt Velocity Starting Empty - All Drives Starting

The above graph shows that the belt accelerates very quickly up to the belt speed of 3.1 seconds. This is because there is 1890 kW installed power and the total power to run the empty belt is only about 225kW, so the Torque available to accelerate the conveyor is too high.

Belt Tensions starting with 3 drives

High belt tensions with large amplitude tension waves are present when starting all three drives with the belt empty.

The following graphs show the same belt started empty with only the one 630kW Secondary drive. The Primary Drive is given a delay time of 10 seconds before starting.

Belt Velocity Starting Empty with secondary drive only

Starting with the Secondary Drive only shows that the conveyor will start satisfactorily without the tendency for the tension waves to push the Drive pulleys to more than full load speed. Starting time is extended to just over 5 seconds from less than 1 second with three drives starting. The primary drive would be allowed to freewheel up to full speed with the belt and then the power would be switched on after the 10 second delay.

Belt Tensions Starting Empty with Secondary Drive only and then Primary Drive Switched in after 10 seconds

Belt tensions are much lower when starting with only the secondary drive and the magnitude of the tension waves is not as large.

Dynamic Analysis Example- Inclined Fabric Belt Conveyor with Holdback

This conveyor is a 1000m long coal conveyor level for 750m with the last 250m rising up 50m in elevation. It has 1500mm wide belt and is running at 3.5m/s with 2500 tph capacity.

The model below shows the conveyor stopping fully loaded with a Holdback device fitted and without a Holdback device fitted.

Design Summary is as follows:

The first Dynamic Calculation run shows the conveyor stopping fully loaded. The conveyor does not have a Holdback device fitted to the Drive.

Belt Velocities Stopping - no Holdback

Drive velocity drops to zero in7.5 seconds

Drive and Tail velocitycontinues to drop andbecomes negative

Belt velocity at Drive drops quickly from 3.5 m/s to 1.3 m/s. Tail pulley velocity is maintained at just under 3.5 m/s by the inertia of the moving belt and material and then drops of after about 2.5 seconds. The Drive pulley reaches zero velocity at 7.5 seconds and this compares with the rigid body calculations where a Stopping time of 7.34 seconds is predicted.

However, the Drive pulley speed continues to drop off and becomes negative, indicating that the pulley is now running backwards. This is because there is no Holdback device fitted.

The following graph shows the Tensions during stopping with no holdback fitted.

Belt Tensions - no holdback

Drive Tension Drops suddenly and stabilises.Tail Tension fluctuates with wave.

From the above you can see that Tension at drive drops suddenly from the 241 kN Running tension to just under 100 kN and then stabilises at the no load tension of 79 kN. Tensions at the tail continue to fluctuate as the standing wave passes through.

Belt Velocities Stopping - with Holdback fitted

Drive Velocity Drops tozero in 7.5 seconds and isprevented from becomingnegative by the holdback

The graph above shows the Drive velocity dropping to zero and then being held at zero by the Holdback device.

Belt Tensions - with holdback

Drive Tension drops and risessteadily as Holdback takesload then stabilises

Holdback Tension

Dynamic Analysis Example - Declined Tail Drive Conveyor

This example shows a Declined conveyor, fitted with a Tail Drive Starting and Stopping. The conveyor is 1600m long and drops 77m over its length. Installed power is a 250kW motor on the Tail drive. The takeup is located at the tail, before the drive.

Declined Conveyor Starting on Velocity Ramp

Declined Conveyor Starting Full Belt Tensions

Tension graphs show how the tension on the tight side of the drive increase dramatically as the motor starts to act as brake. A large tension wave is setup by the braking action of the motor.

Declined Conveyor 3D Graph of Belt Tensions During Starting

above shows the Belt Velocities with a Fully Loaded conveyor when the brake is released. It accelerates under its own power with no outside forces.

Declined Conveyor Stopping under brakes

Belt velocities in graph above show belt coming to a stop about 30 seconds after initiation of the stop. The rigid body calculations show the conveyor will stop in 29.76 seconds so the correlation is very good. The Drive velocity and the velocity of the intersection point on the Tight (during braking) side of the brake pulley is shown in a yellow colour. In order to prevent 'hunting' about the zero velocity, it is best to tick the 'Holdback fitted to Drive' checkbox. This ensures that once the drive pulley stops, it is held at zero velocity by the brake and does not oscillate about the zero velocity point.

Declined Conveyor Belt Tensions Stopping under brakes

Belt Tensions during stopping under brakes above shows the braking force applied - yellow line. The slack side of the brake (red line) has a tension magnitude almost the same as the Takeup tension (black line). The stationary braking force required by a fully loaded conveyor is the magnitude of the Int. Pt line above - about 255 kN.

The Rigid Body calculations show the following tensions during stopping under brakes.

The actual Dynamic tensions at the brake are higher than those indicated by the rigid body calculations.

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