mike cannon vibration analysis: dli engineering corp. automated …vibration.org/presentation/dli...

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Vibration Analysis:AutomatedDiagnostics

Mike CannonDLI Engineering Corp.

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Diagnostic System Development

25,000+ machines in database (since 1972 )

Rules continuously verified & updated

New rules added as unique machines join database

Fault diagnoses analytically & empirically derived

Large machine database, combined with years of repairhistory, and machine life cycle data is foundation fordiagnostic system success

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Keys to a successful program…

Ensure reliable and complete data collected

Ensure you get answers, not just data

Ensure you get First Rate support and training

Use the right technology for the right application

Distribute the information everywhere it is needed forplanning of repairs

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Reliable and complete data

Triaxial Sensor All 3 axes - more complete analysis

Improves accuracy of diagnosis

Permanently Mounted Stud Excellent frequency response

Repeatability = accurate trending

Barcoding Faster and more accurate

Prevents human error

100 100

WATCHMAN TEST POINT

DO NOT PAINT

100 100

WATCHMAN TEST POINT

DO NOT PAINT

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Processing Vibration Data

Level IReports

Level IReports

Level IIISignatures

Level IIISignatures

Level IITrends

Level IITrends

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Level 1 - Reports

Discussion: Raw diagnostic report 93% of erroneous analysis was in stating the severity level

Diagnostic software best equipped to identify obvious faults andadditional faults (complete picture)

Discussion: Engineers 67% of missed faults were where there was more than one fault,

(missed multiple fault diagnosis)

Tended to identify the obvious fault only

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SL

IGH

TE

XTR

EM

E

MARFEB APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEBJAN

= Motor Bearing Wear

Increased Frequencyof Data Collection

Greased BearingReplaced Bearing

Level 2 - Trends

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Tri-axialDisplayTri-axial

DisplayTri-axialDisplay

Single axesDisplay

Single axesDisplay

Level 3 - Signatures

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MACHINE: MAIN CONDENSATE PUMP (TD)SHIP APPLICABILITY: 61,62,63,64CVN63 UNITS: 1B,2B,3B,4B

SWAB: 255-5 MID: 53DATE: DECEMBER 1992

DRIVER INTERMEDIATE DRIVEN

CID#: 05790037MFR DWG#: 347-2918MFR: WHITONHP: 40STEAM CONDITIONS:

Chest: 575 PSIGExhaust: 15 PSIG

RPM: 6410TYPE: HELICAL FLOW,IMPULSE

CID : 05790037TECH MANUAL : 347-2918MFR: WHITONRATIO: 5.479 TO 1RPM (INPUT/OUTPUT):

6410/1170TYPE: SINGLE HELICAL,

DOUBLE REDUCTION

CID : 016000340TECH MANUAL : 347-2918MFR: ALLIS CHALMERSOUTPUT: 595 GPM @ 65 PSIGRPM: 1160TYPE: DOUBLE STAGE,

SINGLE SUCTION,VOLUTE

TEST RPM’s AND OPERATING CONDITIONS

TURBINE: 6400 PUMP: 1168

ANALYSIS RANGES

REF RPM: 1 X TURBINEORDERS: 2, 100FREQ HZ : 220, 11000

What machine is thisWhat machine is this

How does theDiagnostic System work?Incoming SpectraIncoming Spectra

Machinery Knowledge BaseMachinery Knowledge Base

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What machine is thisWhat machine is this

Incoming SpectraIncoming Spectra


VIBRATION SOURCE COMPONENTSDRIVER INTERMEDIATE OR AUXILIARY SHAFTS DRIVEN

ITEM DESCRIPTION ELEM ORDER ITEM DESCRIPTION ELEM ORDER ITEM DESCRIPTION ELEM ORDER

t

Z1

T1S1

G1

AB

Turbine Shaft (ref)

Nozzles90 Degree Spacing

Turbine BladingReversing Chambers

12.6 Degree Spacing10.5 Degree Spacing8.3 Degree Spacing

High Speed Drive Pinion

BEARING FUNCTIONSKF 6211 R,T-tSKF 6211 R-t

3

40

27

1.00t

3.00t4.00t

40.00t

28.60t34.20t43.40t27.00t

I

G2G3G5

o

G6OP

CD

Intermediate Shaft

High Speed Driven GearLow Speed Drive PinionOil Pump Drive Pinion

Oil Pump Shaft

Oil Pump Driven GearOil Pump

BEARING FUNCTIONND 41308 R,T-iND 41308 R, T-i

662925

8112

0.41t

27.00t11.86t10.23t

0.13t

10.23t1.52t

p

G4P1P2

EFGHJ

Pump Shaft

Low Speed Driven Gear2nd Stage Impeller Vanes1st Stage Impeller Vanes

BEARING FUNCTIONTMK 7320 R,T-pTMK 7320 R,T-pMRC 7308 R,T-pMRC 7308 R,T-pJournal R-p

6555

0.18t

11.86t0.91t0.91t

&what are its vibration sources?

How does theDiagnostic System work?

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What machine is this &what are it’s vibration sources

What machine is this &what are it’s vibration sources



High SpeedDrive Pinion

BEARINGSKF 6211BEARINGSKF 6211

Oil Pump


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What machine is this &what are its vibration sources?


How does this spectra compareto that of a healthy machine?

How does this spectra compareto that of a healthy machine? Average Spectra Data BaseAverage Spectra Data Base


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Baseline Data of healthy machineAverage + 1 Sigma Alarm Level

800 Alarm Levels

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What, if anything, is wrong withthis machine and how bad is it?

What, if anything, is wrong withthis machine and how bad is it? Spectral Analysis Rule BaseSpectral Analysis Rule Base


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Diagnostic Program Flow Path

CSDMCSDM

CSDMCSDM

CSDMCSDM

MOTOR

COUPLING

CENTRIFUGAL PUMP

COMPONENTCODES

SCREENINGOUTPUT TABLE

MACHINEDATA

MACHINEDATA

(CSDM = Component Specific Data Matrix)

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16 15Couplings

Component Codes

1Motor Driven

Close CoupledPumps/Fans

2Turbines

4Gearboxes

5Linked Drives(Belt/chain)

6Pumps

Centrifugal

7Rotary Thread

Pumps

8Sliding Vane

Pumps

9Axial Piston

Pumps

10Fans

11Centrifugal

Compressors

12Piston

Compressors

13Generators

14Centrifugal

Purifiers

NOTE:This illustrated set

is not complete

3Motors

3Motors

15Couplings

6Pumps

Centrifugal

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CSDM

CSDM

CSDM

MOTOR

COUPLING

COMPONENTCODES



MACHINEDATA

MACHINEDATA

FAULTTEMPLATES


CENTRIFUGAL PUMP

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18Diagnosis Rules

1. 2X Vertical or Horizontal > .03 IPSand

> 20% above Baseline on both sides of the coupling

3. The Maximum 2X > .06 IPSor

The sum (V & H) of 2X exceedances > 10 times the1X (V & H) for at least one side of the coupling

2. 2X Vertical > 1X Verticalor

2x Horizontal > 1X Horizontal for one side of coupling

--Misalignment (Parallel)

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CSDM

CSDM

CSDM

MOTOR

COUPLING

CENTRIFUGAL PUMP

COMPONENTCODES


MACHINEDATA

MACHINEDATA

FAULTTEMPLATES



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Incoming Spectra

Machinery Fault ReportMachinery Fault Report



What, if anything, is wrong withthis machine and how bad is it?

Maintenance Planning

How does theDiagnosticSystem work?

Answers not just Data

We’ve automated thesame steps a humananalyst follows

It is not a black box!

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Maintenance Planning Schedule immediate repairs (Extreme Faults)

Avoid catastrophic failure or secondary damage

Schedule normal repairs (Serious Faults) Planned outage or maintenance period

Review parts availability (Moderate Faults) Stock long-lead-time parts for critical equipment

Order parts in advance for planned shut downs

Retest following maintenance or replacement Reset baseline & reference information

Verify maintenance was performed correctly


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Common Problems Identified

Imbalance

Misalignment

Ball Bearings

Looseness

Bent shaft

Journal Bearings

Gear Problems

Impeller Blade Problems

Motor Problems

650 more


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A 6 Step Approach to Condition Assessment 1

Data Acquisition (e.g. portable or online data collected from widevariety of sensors)

Data Manipulation (e.g. spectra, waveforms, envelop demodulation,phase or overall level)

State Detection (e.g. create average baseline data to be used forfuture comparison)

Health Assessment (e.g. automated fault diagnostics using rule-base expert system)

Prognostic Assessment (e.g. three levels of repair priority for takingmaintenance actions)

Advisory Generation (e.g. actionable information consists ofmachine severity, specific fault (s), repair recommendation & priority

1 International Standard ISO Standard 133741-1Condition monitoring & diagnostics of machines

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Screens Raw Data from Machine

> 500 Alarm Bands

Actual machine data is thebaseline alarm

Analyst simply selects healthymachine data

Alarm threshold generatedusing statistical models

Provides highly selectivemachine condition (fault,severity & repair priority)

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Automated Fault Diagnostics - Overview

Rule-base expert system,proven over 25 years ofexperience and use

Reduces analysis, diagnosisand report generation by anorder of magnitude comparedto manual analysis programs

Based on five levels of faultseverity and three levels ofrepair priority

Extreme

Serious

Moderate

Slight & OK

Mandatory

Important

NoRecommendation

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Automated Fault Diagnostics - Planning

Schedule immediate repairs (ExtremeFaults) to avoid catastrophic failure orsecondary damage

Schedule normal repairs (SeriousFaults) to plan outage or maintenanceperiod

Review parts availability (ModerateFaults) Stock long-lead-time parts for critical

equipment Order parts in advance for planned

shut downs

Retest following maintenance orreplacement Reset baseline & reference information Verify maintenance was performed

correctly

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Documentation & Actionable Report

Repair Priority

Repair Action /Recommendation

Problem Description withspecific fault severity

Vibration detail showingspecific amplitude andfrequency triggered fault

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Measure - Analyze - Document

Measure / Collect Data Portable or Online

Use other Technologies(Oil, IR, Motor, Ultrasound)

Analyze / Screen Data Time, Spectra, Demodulation,

Run Down, Trends, Waterfall

Document / Report / Distribute Fault, Severity, ACTION

Machine Condition Assessment (MCA)

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Analyze Data – Example: Circ Water Pump

Use ALL the tools available Spectral Pattern Recognition

Spectral Comparison

Trends

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Analyze / Diagnose – Motor Imbalance

Boiler Circulating Water Pump/Motor 1B

Report generated on: 5/30/01 05:44 PM

Acquired: 2/18/98 07:56 PM 1xM = 1794 RPMAverages: 6

Figure of Merit = 360.

Maximum level: 0.1761 (+0.1448) in/s at 1xMon 1R in low range

RECOMMENDATIONS:

IMPORTANT: BALANCE MOTOR

DIAGNOSES:

SERIOUS MOTOR IMBALANCE

Severity Levels:SlightModerateSeriousExtreme

ACTION with PriorityDesirableImportantMandatory

Specific Fault(s)Note: Over 950 faulttemplates availablefor 47 machinetypes/components

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Analyze / Diagnostic Fault Template / Rules

1 x Horizontal > 0.12 ips OR 1 x Vertical > 0.12 ips

1 x Horizontal > average baseline @ Motor

AND 1 x Vertical > average baseline @ Motor

1 x Horiz. Delta + 1 x Vert. Delta @ Motor

> 1 x Horiz. Delta + 1 x Vert. Delta @ Pump

1 x Horiz. > 1 x Axial @ Motor AND

1 x Vert. > 1 x Axial @ Motor

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Analyze / Diagnose - Shaft Misalignment

2X

2X

1X

• At Twice Rotational Rate in the Horizontal& Vertical Directions (parallel)• At the Rotational Rate in the Axialdirection (angular)

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Analyze / Diagnose – Shaft Misalignment Rule-based logic is identical to

human analyst:

High 2x amplitude in radialdirections and 1x in axialdirection

Significant exceedance aboveaverage baseline

Serious Misalignment >>Important repairrecommendation to align unit

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Analyze / Diagnose – Rolling Element Brg

Additional tools Spectral Comparison

Time Waveform

Envelop Demodulation

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Documentation / Report – Bearing Fault

Drain Pump1

Acquired: 8/19/98 10:35 AM 1xM = 1192 RPM Averages: 1

Figure of Merit = 705.

Maximum level: 0.222 (0.024) IPS [3T] at 3.00xM

RECOMMENDATIONS:

MANDATORY: REPLACE MOTOR BEARINGS

DIAGNOSES:

EXTREME MOTOR BEARING WEAR

0.088 (0.084) IPS [2R] at 3.10xM

SLIGHT PUMP INTERNAL LOOSENESS

SLIGHT MOTOR BALL BEARING SIGNIFICANT DEMOD

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Document / Distribute Information

ABB/DLIUSA

ABBAbu DhabiABB

Germany

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Tools for Information Distribution

Database replication / synchronization

Remote, web-based vibration services

Automated alarm notification via pager,text messaging or email

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Tools for Information Distribution

Web-enabled Services

Access to machine data &condition information via yourWeb Browser

View information on anymachine in database

List of Machines by Severity

Automated Diagnostic Results

Spectral Plots

Severity Trends

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Summary

Agreement with human analysts is demonstrated to bein excess of 90%

Study group of 4000 machines of many types.

Basic methods are discussed Speed normalization

Average spectra as a baseline

Cepstrum analysis for bearing tone detection

Component specific data and rules application

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Rulebase Development

Developed through systematic comparison of expert human analysis to the expertsystem analysis results

Original database of over 10,000 machine tests

Rulebase development and refinement continues

Currently our machinery test database grows at a rate of over 2000 machine tests amonth,

Every one of the tests reviewed for expert system versus human analysis agreement as partof an ongoing quality improvement program.

This regular methodical review of the results provides expert system report correctionswhich are forwarded to the plant managers

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Accuracy Study

Machine Tests Reviewed 3971

Correctly Identified Fault Free Machines 2733

Faults Reported 1183*

Correct calls 1106

Faults Missed 77

False Alarms 59

Accuracy Excluding Fault Free Units 87.8%

Accuracy Including Fault Free Units 96.1%

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More Statistics

The probability of:

A good machine being reported by automated system as faultyis 2.1%

The probability of a faulty machine being completely missed byautomated system is 5.8%

The probability of a faulty machine being misdiagnosed byautomated system is 1.4%.

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Methodology Basis 2: Tri-Axial Vibration Data Acquisition

Acquire data for all three axes at each test point. Axial, Vertical and Horizontal (A, V, H).

At least one test location and sometimes two per major machinecomponent isolated-by a flexible coupling.

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Methodology Basis 3: Order Normalized Vibration Data

The expert system automatically finds the running speed of each machine. Order normalizing allows

Analyst or expert system quickly identify peaks

The expert system readily identifies probable bearing tones and detects rotational ratesidebands.

Most important, it allows The creation of an average data file

Combining Vibration signatures for identical machines

different times

slightly different operating speeds

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Methodology Basis 3: Order Normalized Vibration Data

Uses least squares fit between Peaks in the Current data and

Reference peaks

Faultcodes

average peaks

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Methodology Basis 4: Averaged Vibration Data

Accumulated average data is the baseline for automated analysis.

Allows the machines themselves to define an acceptable level ofvibration.

Composed of normalized vibration signatures of:

relatively healthy machines

physically identical machines

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Methodology Basis 5: Vibration Data Screening

Screening routine incorporated by an expert system produces a screening output table which includes the following information for each test location and axis:

Amplitudes at each of ten pre-selected, specified orders, (screening criteria or fault codes) 1x and 2x (one and two times rotational rate), MB (motor bar pass rate) PV (pump vane rate) GR (reduction gear mesh rate) FDN (foundation resonance).

Amplitude and rotational rate order of : the two highest peaks in each of the low range and high range spectra, excluding the ten specified peaks.

“Floor” level below which are the amplitudes of 75% of the remaining spectral lines of the high range spectrum.

For each of the above, change in amplitude deviation from average plus sigma.

Thus we have 14 distinct peaks plus the “floor” noise level tabulated for each axis

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Methodology Basis 6: Cepstrum Analysis for Bearing Wear Detection

Developed to detect and identify harmonics and sidebands, Finds any significant series of regularly spaced peaks in the frequency

spectrum.

A cepstrum can be defined simply as the spectrum of a spectrum.

Characteristic peaks in the cepstral data occur at positions corresponding tofrequencies at which there exists a strong series of peaks or spacings in thespectrum.

A machine with a faulty antifriction bearing may show a harmonic series ofpeaks with 3.12 times rotational rate spacings in the spectral data (i.e. peaks at3.12,6.24,9.36... etc.).

This series of peaks would then show up in the cepstral data as a single peak ata position corresponding to the frequency of 3.12 times rotational rate.

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Methodology Basis 7: Analysis by Component

Close-Coupled MachinesTurbinesMotorsGearboxesLinked Drives (belt or chain)Centrifugal PumpsRotary Thread/Gear PumpsRotary Sliding Vane PumpsReciprocating PumpsFansCentrifugal CompressorsReciprocating CompressorsScrew CompressorsLobed BlowersGeneratorsPurifiersCouplingsDiesel EnginesMarine Propulsion GearboxesMachine Tool Spindles

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CSDMCSDM

CSDMCSDM

CSDMCSDM

MOTORMOTOR

COUPLINGCOUPLING

CENTRIFUGAL PUMPCENTRIFUGAL PUMP

COMPONENTCOMPONENTCODESCODES

SCREENINGSCREENINGOUTPUT TABLEOUTPUT TABLE

(CSDM = Component Specific Data Matrix)(CSDM = Component Specific Data Matrix)

MACHINEDATA

MACHINEDATA

FAULTFAULTTEMPLATESTEMPLATES

Diagnostic Fault Templates / Data Flow

mike cannon vibration analysis: dli engineering corp. automated …vibration.org/presentation/dli...

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