introduction may 2006june 2004 outline - vibration 2006/fluid film... · ·...

Introduction May 2006June 2004

(c) Pioneer Motor Bearing CompanyIntroduction Sheet 1

(c) Pioneer Motor Bearing Company, 2006

IntroductionIntroduction

Pioneer Motor BearingPioneer Motor BearingMay 2006May 2006

VIBRATION INSTITUTEVIBRATION INSTITUTEFLUIDFLUID--FILM BEARINGSFILM BEARINGS


OutlineOutlinenn Pioneer Motor Bearing CompanyPioneer Motor Bearing Companynn Thursday: Journal / Sleeve BearingsThursday: Journal / Sleeve BearingsnnFundamentalsFundamentalsnnOperations impactsOperations impactsnnInstallation / handlingInstallation / handling

nn Friday: Thrust BearingsFriday: Thrust BearingsnnExtension of previous discussionExtension of previous discussion


Pioneer Motor Bearing Co.Pioneer Motor Bearing Co.nn Established in 1920; familyEstablished in 1920; family--owned.owned.nn Offers triad of engineering, new manufacture, Offers triad of engineering, new manufacture,

and repair services related to fluidand repair services related to fluid--film film bearings.bearings.

nn Alliance partner with Alliance partner with MichellMichell BearingsBearingsnn Exclusive repair licensee of Siemens Exclusive repair licensee of Siemens

(Westinghouse) and (Westinghouse) and AlstomAlstom Power in North Power in North America for largeAmerica for large--steam, babbitted products.steam, babbitted products.

nn Proprietary Fluid PivotProprietary Fluid Pivot®® tiltingtilting--pad journal pad journal bearing.bearing.

nn Customized training courses available.Customized training courses available.


(c) Pioneer Motor Bearing Company, 2006 (c) Pioneer Motor Bearing Company, 2006

LocationsLocations

California:California:AdministrationAdministration& Regional Sales& Regional Sales

Philadelphia:Philadelphia:TechnicalTechnicalServicesServices

North Carolina:North Carolina:

EngineeringEngineeringManufacturingManufacturingService & RepairService & Repair




Pioneer Motor BearingPioneer Motor Bearing

Engineering

Manufacturing Service & Repair(c) Pioneer Motor Bearing Company, 2006


Full Spectrum of ServicesFull Spectrum of Services

nnEngineering & Technical Engineering & Technical ServicesServices

nnManufacturing to Manufacturing to CustomersCustomers’’ Designs Designs


nnManufacturing PioneerManufacturing Pioneer’’s s Custom Designs Custom Designs (Including Fluid Pivot(Including Fluid Pivot®®Journal Bearings)Journal Bearings)

nnRepair, Modifications & Repair, Modifications & UpgradesUpgrades

Full Spectrum of ServicesFull Spectrum of Services


EngineeringEngineeringLyle A. BranaganEngineering ManagerBSME, MS, Ph.D.

– 10 years with PG&E– Has substantial knowledge of rotor dynamics of turbomachinery– Extensive experience in the field– An expertise in fluid film bearings and seals


Dr. Lyle A. BranaganDr. Lyle A. BranagannnEngineering ManagerEngineering ManagernnBSME / MSME BSME / MSME –– Machinery dynamicsMachinery dynamicsnnPhD PhD –– FluidFluid--film bearing analysisfilm bearing analysisnnUniversity of Virginia University of Virginia –– ROMAC LabROMAC Lab

nn IndustriallyIndustrially--accepted design codesaccepted design codes

nnPacific Gas & Electric Pacific Gas & Electric –– 10 years10 yearsnnSpecialist in bearings and rotordynamicsSpecialist in bearings and rotordynamics

nnKnolls Atomic Power LabKnolls Atomic Power LabnnPioneer Motor Bearing Pioneer Motor Bearing –– 10 years10 years




Fred C. WiesingerFred C. Wiesinger

Office in Lansdale, PAOffice in Lansdale, PA11--(215) 362(215) 362--40744074

Technical Services Manager•Expertise in high speed gearboxes

•Expertise in thrust bearings

•Expertise in bearing repair services


Frederick (Fred) C. WiesingerFrederick (Fred) C. WiesingerTechnical Services ManagerTechnical Services Managernn Drexel UniversityDrexel University

nn BSME With HonorsBSME With Honorsnn Philadelphia Gear Philadelphia Gear –– 7 Years7 Years

nnManager High Speed Gear BoxesManager High Speed Gear Boxes

nn Kingsbury, Inc. Kingsbury, Inc. –– 14 Years14 Yearsnn Chief EngineerChief EngineernnManager, Repair & Service DivisionManager, Repair & Service Divisionnn Vice President, ManufacturingVice President, Manufacturing

nn Turbo Research, Inc. Turbo Research, Inc. –– 3 3 ½½ YearsYears


Presentation GoalsPresentation Goals

••Understand operation of Understand operation of fluidfluid--film bearingsfilm bearings••Relate vibration changes Relate vibration changes to potential bearing to potential bearing changeschanges


TopicsTopicsnn Abbreviated from 8Abbreviated from 8--12 hour training 12 hour training

classclassnn Introduction Introduction nn Journal bearing overviewJournal bearing overviewnn Lining overviewLining overviewnn Lubricant overviewLubricant overviewnnWear overviewWear overviewnnBabbittedBabbitted bearing damagebearing damagenn RotordynamicsRotordynamics / journal bearings/ journal bearingsnn Predictive maintenance interfacePredictive maintenance interfacenn Installation and handlingInstallation and handlingnnQuestions and discussionQuestions and discussion


Topics Topics –– FridayFridayFocus on Thrust (Axial) BearingsFocus on Thrust (Axial) BearingsnnThrust bearing overviewThrust bearing overviewnnBabbittedBabbitted bearing damagebearing damagennRotordynamicsRotordynamics / thrust bearings/ thrust bearingsnnPredictive maintenance interfacePredictive maintenance interfacennInstallation and handlingInstallation and handlingnnQuestions and discussionQuestions and discussion


DemonstrationsDemonstrationsnnViscosityViscositynnHydrodynamic filmHydrodynamic filmnnCavitationCavitationnnSlinger ring operationSlinger ring operation




Perspectives on BearingsPerspectives on BearingsnnPioneer Motor Bearing CompanyPioneer Motor Bearing CompanynnPower Plant or Manufacturing PlantPower Plant or Manufacturing PlantnnMaintenanceMaintenancennMachine DesignerMachine DesignernnLubricant VendorLubricant VendornnVibration SpecialistVibration Specialist


A A ““smallsmall”” piece in the plantpiece in the plant


With the With the potential potential to cause:to cause:

Avoid Frustration, Extra Work, Late Nights, Lost ProductionAvoid Frustration, Extra Work, Late Nights, Lost Production

GOAL:GOAL:


Machine Design PerspectiveMachine Design PerspectivennAllow rotating equipment to operateAllow rotating equipment to operatennSeparate rotating and stationary Separate rotating and stationary

componentscomponentsnnSupport the rotating loadSupport the rotating loadnnControl Control rotordynamicsrotordynamicsnnRequiresRequiresnnSupportSupportnnAdequate coolingAdequate coolingnnLubricant flowLubricant flow


Lubricant PerspectiveLubricant PerspectivennLubricant to satisfy requirementsLubricant to satisfy requirementsnnViscosityViscositynnProper additivesProper additives

nnAdequate operational lifeAdequate operational lifennUnderstand impact on oil analysisUnderstand impact on oil analysis


Vibration Specialist PerspectiveVibration Specialist Perspectivenn Common point of measurement for Common point of measurement for

vibrationvibrationnn Potential interaction of sensors and sensor Potential interaction of sensors and sensor

mountingmountingnnDefines the measured quantityDefines the measured quantity

nnMay define allowable vibrationMay define allowable vibrationnnBearing clearanceBearing clearancenn Allowable bearing loads, esp. dynamicAllowable bearing loads, esp. dynamic

nn Faults may affect vibration signatureFaults may affect vibration signaturenn Excessive vibration may affect bearingsExcessive vibration may affect bearings




EndEnd

IntroductionIntroduction

May 2006May 2006

(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 11

(c) Pioneer Motor Bearing Company, 2006. All rights reserved.

BabbittedBabbitted Bearing OverviewBearing Overview

Pioneer Motor Bearing CompanyPioneer Motor Bearing CompanyAugust 2006August 2006

PIONEER FLUIDPIONEER FLUID--FILM BEARING WORKSHOPFILM BEARING WORKSHOP


FluidFluid--Film BearingsFilm BearingsAPPLICATIONS:APPLICATIONS:nnRadial turbine, generator, fan, Radial turbine, generator, fan,

pump, and motor bearingspump, and motor bearingsnnTurbine, generator, fan, pump, and Turbine, generator, fan, pump, and

motor thrust bearingsmotor thrust bearingsnnGenerator hydrogen and other high Generator hydrogen and other high

pressure sealspressure seals


OutlineOutlinenn Radial bearingsRadial bearingsnnBore designBore design

nn Thrust bearingsThrust bearingsnn Profile designsProfile designs

nn FluidFluid--film bearing film bearing analysisanalysisnn Reynolds equationReynolds equation


Opening Up the MachineOpening Up the Machine

Bearing integral Bearing integral with shellwith shell

Bearing Bearing bolted to bolted to machine or machine or mounted in mounted in end bell.end bell.


Opening Up the BearingOpening Up the Bearing

End bell and housing top removedEnd bell and housing top removed

Upper half Upper half and and lower half lower half showing IDshowing ID


Load Orientations: Load Orientations: radial/thrustradial/thrust

May 2006May 2006



Load Orientations: Load Orientations: radial/thrustradial/thrust

nn Horizontal machineHorizontal machinenn Radial bearingRadial bearing

nn Gravity loadGravity loadnn Radial process / misalignment loadsRadial process / misalignment loads

nn Thrust (axial) bearingThrust (axial) bearingnn Axial process loadsAxial process loads

nn Vertical machineVertical machinenn Radial bearingRadial bearing

nn Radial process / misalignment loadsRadial process / misalignment loadsnn Thrust bearingThrust bearing

nn Gravity loadGravity loadnn Axial process loadsAxial process loads


Radial BearingsRadial Bearings


Thrust BearingsThrust Bearings


ElementsElementsnnFunctionFunctionnnPurpose of a fluidPurpose of a fluid--film bearingfilm bearing

nnGeometryGeometrynnKey featuresKey features

nnHydrodynamic theoryHydrodynamic theorynnMaterialsMaterialsnnLiner and supportLiner and support

nnLubricant supplyLubricant supply


FunctionFunction1.1. Separate rotating from nonSeparate rotating from non--rotating rotating

componentscomponentsnn ClearanceClearance

2.2. Transfer loads (static and dynamics) Transfer loads (static and dynamics) from the rotating to the stationary from the rotating to the stationary structurestructurenn Force transmissionForce transmission

3.3. Prevent undesirable vibrationsPrevent undesirable vibrationsnn Primary source of dampingPrimary source of damping

4.4. Provide cooling Provide cooling


SeparationSeparationnnMaintain close clearancesMaintain close clearancesnnMotors / Generators windingsMotors / Generators windingsnnFan seals and bladesFan seals and bladesnnTurbine bladesTurbine blades

May 2006May 2006



Hydrodynamic versus HydrostaticHydrodynamic versus Hydrostatic

nn Hydrodynamic Hydrodynamic –– pressure pressure induced by relative motion.induced by relative motion.

nn Hydrostatic Hydrostatic –– pressure pressure supplied by external supplied by external source.source.


Hydrodynamic versus HydrostaticHydrodynamic versus Hydrostatic

Ref: Intelligent Mechanics Lab, Ref: Intelligent Mechanics Lab, PukyongPukyong University, websiteUniversity, website


Sleeve Bearing GeometrySleeve Bearing GeometryRotatingRotatingJournalJournal

HousingHousing

ShellShellBabbittBabbitt

END VIEWEND VIEWCLEARANCECLEARANCEEXAGGERATEDEXAGGERATED

ROTATINGROTATINGJOURNALJOURNAL

SHELLSHELL

BABBITTBABBITT CLEARANCECLEARANCE


General ClearanceGeneral Clearance

CLEARANCE GREATLY EXAGGERATEDCLEARANCE GREATLY EXAGGERATED

ROTATINGROTATINGJOURNALJOURNAL

SHELLSHELL

BABBITTBABBITT CLEARANCECLEARANCE

CONVERGINGCONVERGINGCLEARANCECLEARANCE

DIVERGINGDIVERGINGCLEARANCECLEARANCE

XX

0 90 180 270 3600

5

10

15

20

25

30

35

40CLEARANCE

Circumferential Position

Cle

aran

ce

36

4

hd θ( )mil

3600 θdeg

CONVERGING

DIV

ERG

ING

Clearance Clearance space is filled space is filled by a lubricant.by a lubricant.


ClearanceClearance

nnAssume 0.009Assume 0.009”” radial clearance radial clearance on a centered 12on a centered 12”” diameter diameter bearingbearing

Human hair aboutHuman hair about0.0030.003”” diameterdiameter

JOURNALJOURNAL

BEARINGBEARING

By comparison, the By comparison, the minimum operating minimum operating clearance is only clearance is only about 0.002about 0.002””..


ClearanceClearancennAssume 230 Assume 230 µµm (0.009m (0.009””) radial ) radial

clearance on a centered 300 mm clearance on a centered 300 mm (12(12””) diameter bearing) diameter bearing

Human hair aboutHuman hair about75 75 µµm (0.003m (0.003””) diameter) diameter

JOURNALJOURNAL

BEARINGBEARING

By comparison, the By comparison, the minimum operating minimum operating clearance is only about clearance is only about 50 50 µµm (0.002m (0.002””).).

May 2006May 2006



FluidFluid--Film BearingFilm BearingCritical Geometry:Critical Geometry:nn Clearance space between the rotating Clearance space between the rotating

and stationary componentsand stationary componentsnnCONVERGING SPACES develop pressureCONVERGING SPACES develop pressurennCircumferential grooves carry flowCircumferential grooves carry flownn Axial grooves spread flowAxial grooves spread flownn Tilting pads reduce crossTilting pads reduce cross--coupled forces coupled forces

nn Size on the order of 0.001Size on the order of 0.001””--0.0500.050”” (40(40--2000 2000 µµm)m)


nnDetermine hydrodynamic (Determine hydrodynamic (ωω>0) or >0) or hydrostatic pressures (hydrostatic pressures (ωω=0).=0).

nnCorrections for turbulence (Corrections for turbulence (GGθθ and and GGzz) ) and crossand cross--film viscosity variations film viscosity variations ((µµ(y)).(y)).

Reynolds EquationReynolds Equation

∂∂ µ

∂∂

∂∂ µ

∂∂

ω ∂∂

∂∂x

h Px z

h Pz

R hx

ht

Vthru3 3

12 12 2

+

= + +

Circumferential Axial Shear Squeeze Cross Flow Flow Flow Flow Flow


Sleeve Bearing GeometrySleeve Bearing Geometry

ConvergingConvergingFilm w/CCW Film w/CCW rotationrotation


Bearing PressuresBearing Pressures (Load Capacity)(Load Capacity)

Pressures developed in Pressures developed in the lubricant due to the lubricant due to the converging wedge the converging wedge provide the bearing provide the bearing load capacityload capacity

Theoretical negative Theoretical negative pressures in the pressures in the diverging region are diverging region are cancelled by air flow cancelled by air flow from the axial ends.from the axial ends.


Reynolds Equation Reynolds Equation –– 22--D ProfileD Profile

PRESSUREPRESSURE


Sleeve Bearing FlowsSleeve Bearing Flows

Strong rotation with Strong rotation with shaft; average velocity shaft; average velocity about about ½½ shaft surface shaft surface velocity.velocity.

Lower, Lower, pressure pressure driven axial driven axial velocity.velocity.

May 2006May 2006



Reynolds Equation Reynolds Equation -- CavitationCavitation

““CavitationCavitation”” region, region, present in the upper present in the upper half, generally half, generally occurs by air occurs by air penetration, less penetration, less frequently by oil frequently by oil vaporization. vaporization.


CavitationCavitationDiverging Film Diverging Film -------- >> Converging Film Converging Film -------- >>

Axial distribution:Axial distribution:Area at minimum film limits the flow available.Area at minimum film limits the flow available.Downstream volume is only partially filled.Downstream volume is only partially filled.


Bearing CavitationBearing Cavitation

Axial Axial distribution:distribution:

Area at minimum Area at minimum film limits the film limits the flow available.flow available.

Downstream Downstream increased volume increased volume is only partially is only partially filled.filled.

Minimum Minimum FilmFilm Air intrusionAir intrusion

Air intrusionAir intrusion


Bearing CavitationBearing Cavitation

Axial distributionAxial distribution

Radial Radial distributiondistribution


Cavitation Cavitation -- ExperimentalExperimental

PlexiglassPlexiglass bearing bearing showing the formation showing the formation of cavitation in the of cavitation in the region of increasing film region of increasing film thickness.thickness.

Ref. Cole and Hughes, Ref. Cole and Hughes, Proc.Inst.Mech.EngrProc.Inst.Mech.Engr.., , 170/17, 1956.170/17, 1956.


Cavitation DemonstrationCavitation DemonstrationnnManualManualnnTake (2) small platesTake (2) small platesnnSpread thin layer of greaseSpread thin layer of grease

nnPress plates together with grease in Press plates together with grease in betweenbetween

nnOpen plates from one sideOpen plates from one sidennObserve pattern of greaseObserve pattern of grease

nnDemonstration rigDemonstration rig

May 2006May 2006



FluidFluid--film Radial Bearingfilm Radial BearingnnSleeve around shaft controls Sleeve around shaft controls

radial position.radial position.nnMaximum load capacityMaximum load capacitynnSimple sleeve bearingSimple sleeve bearing

nnMaximum Maximum rotordynamicrotordynamicstabilitystabilitynnTiltingTilting--pad bearingpad bearing


Hydrodynamic DemonstrationHydrodynamic Demonstration

Feel:Feel:

••Reduction in friction Reduction in friction of dry versus of dry versus lubricated.lubricated.

Observe:Observe:

•• Film Film cavitationcavitation


Bore DesignsBore Designs

Define the Define the bore geometry bore geometry for the desired for the desired operating operating characteristicscharacteristics


Bore DesignsBore Designs

Pressures in Pressures in an elliptical an elliptical bearing at light bearing at light loads.loads.

Pressures in Pressures in an offsetan offset--half half bearing.bearing.

Additional Additional effect of a effect of a pressure dam pressure dam –– adds to the adds to the pressures from pressures from the cylindrical the cylindrical lower half.lower half.


Radial Bearing ComponentsRadial Bearing Components

INSULATED RADIAL INSULATED RADIAL BEARING WITH BEARING WITH BUMPER THRUST BUMPER THRUST SURFACESSURFACES

BUMPER THRUST FACEBUMPER THRUST FACE

OUTER OUTER DIAMETER DIAMETER INSULATED INSULATED ON FIT ON FIT AREASAREAS

ANTIANTI--ROTATION PIN HOLEROTATION PIN HOLE

LOWER HALFLOWER HALF UPPER HALF (ROTATED)UPPER HALF (ROTATED)

BOLT HOLESBOLT HOLES

SPLITLINESPLITLINE

SLINGER RING GROOVESLINGER RING GROOVE


Radial Bearing ComponentsRadial Bearing Components

LOWER HALFLOWER HALF UPPER HALF (ROTATED)UPPER HALF (ROTATED)

DOWEL PINSDOWEL PINSOIL COLLECTION POCKETSOIL COLLECTION POCKETS

SIDEWELLSSIDEWELLS

BOLT HOLESBOLT HOLES

SLINGER RING GROOVESLINGER RING GROOVE

May 2006May 2006



Joint DetailsJoint DetailsOilOil--tight metaltight metal--toto--metal joint between metal joint between the bearing halves.the bearing halves.Top half secured by Top half secured by by (4) joint bolts.by (4) joint bolts.Alignment of top to Alignment of top to bottom half by (2) bottom half by (2) dowel pins. Pins dowel pins. Pins captured in the lower captured in the lower half.half.


Dowel PinsDowel Pins

DamagedDamaged

Used to control alignment:Used to control alignment:

•• Bearing shell halvesBearing shell halves

•• Seal retainers to shellSeal retainers to shell

Unhardened allows Unhardened allows deformation of the pin. deformation of the pin. Hardened dowels may Hardened dowels may damage shell under damage shell under excess loading.excess loading.

Care required to separate Care required to separate doweled pieces to avoid doweled pieces to avoid upset to the pieces or the upset to the pieces or the dowel.dowel.


AntiAnti--Rotation PinsRotation PinsProvides:Provides:

Locates shell in housingLocates shell in housing•• AxialAxial•• CircumferentialCircumferential

Prevent rotation of the shell Prevent rotation of the shell in the housing.in the housing.


Bearings for MotorsBearings for Motors

Insulation Insulation required.required.

Potential Potential damaging damaging electrical electrical ground ground current current loops.loops.

Ref: EPRI Manual.Ref: EPRI Manual.


Bearing InsulationBearing Insulation

OD insulation on a motor bearingOD insulation on a motor bearing

Double insulated liner Double insulated liner for exciter bearing.for exciter bearing.

Insulation to prevent Insulation to prevent electrical discharge across electrical discharge across bearing surface.bearing surface.

Potential damaging current loops.Potential damaging current loops.


Bearing SupportBearing Support

FreeFree--standing pedestalstanding pedestal

Motor / Motor / generator end generator end bellbell

Bearing Bearing housing on housing on integral integral pedestal.pedestal.

May 2006May 2006



Conforming Bearing to ShellConforming Bearing to ShellnnDepends on the flexibility (stiffness) Depends on the flexibility (stiffness)

of the bearing:of the bearing:nnThinThin--shell bearingsshell bearings

nnLiner typeLiner typenn Insert typeInsert type

nnMedium wall bearingsMedium wall bearingsnnThick wall bearingsThick wall bearings


DistributionDistribution--Precision HalvesPrecision Halves

Oil distributionOil distributionfeaturesfeatures

Common in Common in reciprocatingreciprocatingand gear box and gear box service.service.

Circumferential groove sharply diminishes load capacity but alloCircumferential groove sharply diminishes load capacity but allows ws for wider range of load angle.for wider range of load angle.


Shell Wall ThicknessShell Wall ThicknessThin wall Thin wall ((““linerliner”” type): type): shell conforms shell conforms to the housing to the housing geometry.geometry.

t < 0.03D t < 0.03D


Shell Wall ThicknessShell Wall ThicknessThick wall: Thick wall: shell is shell is supported by supported by and aligned in and aligned in the housing the housing but retains its but retains its own shape.own shape.

t > 0.1Dt > 0.1D


Shell Wall ThicknessShell Wall ThicknessMedium wall: Medium wall: shell is shell is supported by supported by and aligned in and aligned in the housing the housing but but ““somewhatsomewhat””conforms to the conforms to the housing housing geometry.geometry.


Tilting Pad Radial BearingsTilting Pad Radial Bearingsnn Enhanced Enhanced

rotordynamicrotordynamicstabilitystability

nn Enhanced control Enhanced control of oil flowsof oil flows

nnMore componentsMore componentsnn Higher costHigher cost

May 2006May 2006



TiltTilt--pad Radial Bearingspad Radial Bearingsnn TiltTilt--pad radial bearingspad radial bearingsnnUsed to increase Used to increase rotordynamicrotordynamic stabilitystability

nn Avoid selfAvoid self--excited vibrationsexcited vibrations

nn Segmented load bearing surfaceSegmented load bearing surfacennMechanical pivot Mechanical pivot –– load focused on a single load focused on a single

contact point (contact point (HertzianHertzian contact stress)contact stress)nn Line pivotLine pivotnn Spherical pivot (e.g. ball in socket)Spherical pivot (e.g. ball in socket)

nn Fluid PivotFluid Pivot®®

n No mechanical load concentration

nn Flooded or directed lubrication Flooded or directed lubrication


Mechanical PivotMechanical PivotShaft load Shaft load distributed as distributed as oil pressure and oil pressure and concentrated in concentrated in pad to the pivot pad to the pivot (either a (either a circular or circular or elliptical elliptical contact region). contact region).

Pressure will Pressure will balance around balance around the pivot.the pivot.

PRESSUREPRESSURE PRESSURE

PRESSURE

Pivot can be hardened material (e.g. Pivot can be hardened material (e.g. E52100 tool steel).E52100 tool steel).


TiltTilt--pad Radial Bearingspad Radial BearingsnnNumber of padsNumber of padsnn3, 4 or 5 typical3, 4 or 5 typicalnnDivides the load vectorDivides the load vector

nnOrientationOrientationnnLoad between padsLoad between padsnnLoad on padLoad on pad

nnPreloadPreloadnnDifference in pad curvature and Difference in pad curvature and

assembled bore sizeassembled bore size


PreloadPreloadRpRp –– pad curvaturepad curvature

RbRb –– assembled boreassembled bore

R R –– journaljournal

CC’’ –– assembled assembled clearanceclearance

C C –– pad clearancepad clearance

M = 1 M = 1 –– CC’’/C/C


Tilting Pad BearingsTilting Pad Bearings55--padpad

Load between padLoad between pad

Flooded designFlooded design

Mechanical pivotMechanical pivot

Hydrostatic liftHydrostatic lift


Tilting Pad BearingsTilting Pad BearingsSegmented filmSegmented film

Concentrated loadConcentrated load

Single point, or lineSingle point, or lineContact supportContact support

May 2006May 2006



Specialty Journal BearingsSpecialty Journal BearingsnnTilting pad bearingsTilting pad bearingsnnUses continuing to expandUses continuing to expandnnAlternative pivotsAlternative pivots

nnBall & socket designsBall & socket designsnnFlexure PivotFlexure Pivot®®nnFluid PivotFluid Pivot®®


Pivot TypesPivot Types

LineLine

ContactContact


Conventional Pivot TypesConventional Pivot Types

CYLINDRICALCYLINDRICAL SPHERICALSPHERICAL BALLBALL--ININ--SOCKETSOCKET


Quality of Pivot ContactQuality of Pivot Contact

Contact Contact varies with varies with curvature, curvature, load, and load, and temperature.temperature.


BallBall--inin--Socket Pivot ContactSocket Pivot Contact

Contact extent Contact extent varies with varies with curvature, load, curvature, load, and and temperature.temperature.

Operation Operation requires sliding, requires sliding, as well as as well as rolling, motion rolling, motion at the loaded at the loaded contact.contact.


Flexure PivotFlexure Pivot®®

Ref: KMC Bearing web site.Ref: KMC Bearing web site.

Tilting action Tilting action through through deformation.deformation.

Smaller bearings Smaller bearings benefit from the benefit from the lack of a 2lack of a 2ndnd

tolerance for a tolerance for a detached pad.detached pad.

May 2006May 2006



Stability Variation with Tilt Restraint

0

200

400

600

800

1000

0 0.2 0.4 0.6 0.8 1 1.2

Restraint (dim)

Stab

ilit

y (d

im)

Pivot DesignsPivot DesignsnnTilt Freedom as a Function of:Tilt Freedom as a Function of:

HertzianHertzian contact area or web thicknesscontact area or web thickness

idideal tilt eal tilt pad pad

fifixed padxed pad


Shell, pads, stop pinsShell, pads, stop pins

Fluid PivotFluid Pivot®® -- Tilt Pad BearingTilt Pad Bearing

Hydrostatic pivot,Hydrostatic pivot,NOT a mechanicalNOT a mechanicalpivot.pivot.


Bearing includes Bearing includes shell, pads, stop pinsshell, pads, stop pins

JS Fluid PivotJS Fluid Pivot®®

3 pad ring

Shown as Load-On-Pad

Hydrostatic pivot, NOT a Hydrostatic pivot, NOT a mechanical pivot. On overload mechanical pivot. On overload pad OD sits on shell ID.pad OD sits on shell ID.


Fluid PivotFluid Pivot®®

FlangeFlange--mounted, style JCmounted, style JC

Gear box, style JCGear box, style JC

Pedestal mounted, style JSPedestal mounted, style JS


Fluid PivotFluid Pivot®®

Pad supported on Pad supported on selfself--generated generated hydrostatic film on hydrostatic film on the OD of the pad.the OD of the pad.


Fluid PivotFluid Pivot®® Exciter AssemblyExciter Assembly

May 2006May 2006



EndEnd

Bearing Bearing Fundamentals IFundamentals I

August 2004August 2004



BabbittedBabbitted Bearing OverviewBearing OverviewPart IIPart II

Pioneer Motor Bearing CompanyPioneer Motor Bearing CompanyMay 2006May 2006

VIBRATION INSTITUTE SEMINARVIBRATION INSTITUTE SEMINARCHARLOTTE, NCCHARLOTTE, NC


Oil System Design OptionsOil System Design Optionsnn Lubricant selection and maintenanceLubricant selection and maintenance

nn Viscosity grade and viscosity indexViscosity grade and viscosity indexnnCleanlinessCleanliness

nn Supply optionsSupply optionsnn PressurePressure--fedfednn Slinger ringSlinger ringnn Rotating diskRotating disknn Vertical sumpVertical sump

nn Hydrostatic lift systemsHydrostatic lift systems


Oil Distribution GeometryOil Distribution Geometry

OIL INLET OIL INLET HOLEHOLE

Radial grooveRadial groove

Axial grooveAxial grooveBleederBleeder

BleedersBleeders

Spreader

Groove

Spreader

Groove


Oil Groove GeometryOil Groove Geometry

Double loop groove & double figure eight groove recommended for grease only.

CircularStraightHalf Eight

Double Figure Eight

Double Loop

Straight &

Circular

Figure Eight

Single Loop

Grease grooving often passes thru the loaded region Grease grooving often passes thru the loaded region which reduces the bearing load capacity.which reduces the bearing load capacity.Do not use grooving associated with grease (long Do not use grooving associated with grease (long residence time) with oil lubrication (cooling flow).residence time) with oil lubrication (cooling flow).


Options ComparedOptions Compared

Ref. Constantinescu, Ref. Constantinescu, Sliding BearingsSliding Bearings, , AllertonAllerton, 1985, p.474., 1985, p.474.

Want to have Want to have 100% cooling 100% cooling efficiency and efficiency and 100% 100% hydrodynamic hydrodynamic fluidfluid--film.film.

Best achieved Best achieved with with pressurized oil pressurized oil supply was supply was effective axial effective axial distribution.distribution.


Main oil pump is shaft drivenMain oil pump is shaft driven

AC & DC pumpsAC & DC pumps

Sample Turbine Oil SystemSample Turbine Oil System

Schematic of Schematic of TurbineTurbine--Generator Generator Lubrication Lubrication SystemSystem

Each bearing has a separate Each bearing has a separate pressurized supply (20 psig), pressurized supply (20 psig), orificeorifice--metered, with a gravity metered, with a gravity (or slight vacuum) drain back to (or slight vacuum) drain back to the reservoir.the reservoir.




Turbine Oil System ComponentsTurbine Oil System ComponentsnnLarge capacityLarge capacitynnCoolingCoolingnnFilteringFilteringnnOften uses a loop filterOften uses a loop filter

nnSettlingSettlingnnContaminants Contaminants –– water & dirtwater & dirt

nnContamination controlContamination controlnnBreather Breather –– same or better filter than same or better filter than

the direct oil filterthe direct oil filter

SETTLING TIMESETTLING TIME

5050--micron silica particle: 12 minutesmicron silica particle: 12 minutes5050--micron steel particle: 2.1 minutesmicron steel particle: 2.1 minutes5050--micron copper particle: 48 secondsmicron copper particle: 48 seconds5050--micron chromium particle: 2.5 minutesmicron chromium particle: 2.5 minutes


Slinger RingsSlinger RingsSlinger rings deliver oil from a reservoir below the bearing to the top of the rotating shaft, driven by friction between the rotating shaft and the ring.


Oil Grooving and DistributionOil Grooving and Distribution

Axial Axial distributiondistribution

Mechanical Mechanical oil feedoil feed

Circumferential Circumferential collection groovecollection groove

A ring, rotating by means of friction A ring, rotating by means of friction between the ring and the journal, between the ring and the journal, lifts oil from the reservoir where it is lifts oil from the reservoir where it is sprayed into the top half of the sprayed into the top half of the bearing and directed to the loaded bearing and directed to the loaded half.half.

Ref. Ref. ElwellElwell and and BooserBooser, , Machine DesignMachine Design, , 12/7/69, pp.11112/7/69, pp.111--115.115.


Slinger RingsSlinger Rings

Shaft

Slinger ring

Oil level (normal)

Bearing Babbitt

Ref: Mike King, Palisades Ref: Mike King, Palisades Nuclear Station reportNuclear Station report

Slinger ring ID Slinger ring ID generally about generally about twice the journal twice the journal OD.OD.

Oil level depth Oil level depth above slinger above slinger ring ID roughly ring ID roughly 10% of ID.10% of ID.

Ring driven by Ring driven by shaft rotation.shaft rotation.


Slinger RingsSlinger Ringsnn Important to beImportant to bennInIn--planeplanennConcentricConcentricnnCircularCircular

nnRing speed is a fraction of the shaft Ring speed is a fraction of the shaft running speedrunning speed

nnOil depth is importantOil depth is importantnnBalance oil lift (submergence of the ID) Balance oil lift (submergence of the ID)

with ring dragwith ring drag


Split Slinger RingsSplit Slinger Rings

Trapezoidal Trapezoidal crosscross--sectionsection




Slinger Ring GuidesSlinger Ring Guides

Subject to wear or Subject to wear or damage, particularly if damage, particularly if misapplied.misapplied.

Seek to Seek to maintain rings maintain rings perpendicular perpendicular to shaft to shaft without without introducing introducing metalmetal--toto--metal metal frictionfriction. . Made Made of bronze, of bronze, steel, or steel, or aluminum.aluminum.


Cast Slinger Ring GuideCast Slinger Ring Guide

Cast aluminum guide Cast aluminum guide with oil scraper with oil scraper arrangement. Single arrangement. Single screw bolts guide upward screw bolts guide upward into upper shell. Guide into upper shell. Guide or screw should be or screw should be staked to avoid looseness staked to avoid looseness or rotation. or rotation.

This guide showed This guide showed rubbing wear on the rubbing wear on the upper part of the guide.upper part of the guide.


Slinger Ring ObservationSlinger Ring Observation““Bulls eyeBulls eye””for viewing for viewing the rotation the rotation of the slinger of the slinger ring.ring.

Ref: Mike King, Ref: Mike King, Palisades Nuclear Palisades Nuclear Station reportStation report

Level indicator Level indicator should show should show change from change from static to static to operating oil operating oil level in level in reservoir.reservoir.


Slinger Ring ObservationSlinger Ring Observation


Hybrid SystemHybrid SystemnnCombination of slinger ring and Combination of slinger ring and

pressurized system.pressurized system.nnForced sump coolingForced sump coolingnnShaft driven main oil supplyShaft driven main oil supply


Slinger Ring DemonstrationSlinger Ring Demonstrationnn Three slinger ring Three slinger ring

designsdesignsnn TT--shape: common, shape: common,

inexpensiveinexpensivenn Trapezoidal: Trapezoidal:

heavier, highheavier, high--speedspeed

nn Trapezoidal with Trapezoidal with grooves:grooves:nn Best oil flowBest oil flow




Rotating Disk LubricationRotating Disk Lubrication

Rotating disk, attached to Rotating disk, attached to the shaft, lifts oil from the the shaft, lifts oil from the reservoir. A fixed scraper at reservoir. A fixed scraper at the top directs the oil to slots the top directs the oil to slots or holes at the top of the or holes at the top of the bearing.bearing.

Ref. Ref. BooserBooser, , Handbook Handbook of Lubrication IIIof Lubrication III, 1994, , 1994, pp521.pp521.

BearingBearing


Vertical SumpVertical SumpRotating sleeve pumps oil into a Rotating sleeve pumps oil into a circumferential groove on the circumferential groove on the bearing. Bearing partially flooded.bearing. Bearing partially flooded.

ExplodedExplodedViewView

Issues: Oil height, reservoir pressure, oil temperature, hole aIssues: Oil height, reservoir pressure, oil temperature, hole alignmentlignment


Vertical SumpVertical Sump

Upper guide bearing runs above Upper guide bearing runs above nominal oil level, supplied by nominal oil level, supplied by longer rotating holes. Includes longer rotating holes. Includes ““inactiveinactive”” thrust bearing on the thrust bearing on the lower surface.lower surface.

Issues: Oil height, reservoir pressure, oil temperatureIssues: Oil height, reservoir pressure, oil temperature


Vertical SumpVertical Sump

PartiallyPartially--flooded with pressureflooded with pressure--driven grooves to lift the oil driven grooves to lift the oil for rotation in either direction.for rotation in either direction.


Oil Level IndicationOil Level IndicationnnSight glassSight glassnnMark normal elevation of oil in sumpMark normal elevation of oil in sumpnnElevation will change during operationElevation will change during operationnnMeasurement is at a specific point on Measurement is at a specific point on

the reservoirthe reservoirnnSight glass must be ventedSight glass must be vented


Incorrect Oil Level IndicationIncorrect Oil Level Indication

Shaft

Slinger ring

Bearing Babbitt

Bearing Housing

Oil level (As found)

Oil fill lineOil level (As found in level indicator)

Ref: Mike King, Ref: Mike King, Palisades Nuclear Palisades Nuclear Station reportStation report

Angled oil line allowed Angled oil line allowed residual oil to be mistaken residual oil to be mistaken for the actual oil level for the actual oil level resulting in operation with resulting in operation with minimal, if any, circulating minimal, if any, circulating oil.oil.

Target oil levelTarget oil level




Automatic Automatic OilerOiler

Ref: Malinowski, Trico CorporationRef: Malinowski, Trico Corporation

Proper venting, Proper venting, alignment, and filling alignment, and filling beneficial to correct beneficial to correct operation.operation.


Automatic Automatic OilerOiler

Ref: Malinowski, Trico CorporationRef: Malinowski, Trico Corporation


Oil Flow ObservationOil Flow ObservationInlet or drain Inlet or drain flow;flow;

FullFull--flow or byflow or by--pass;pass;

Ease of access;Ease of access;

May be May be combined with combined with drain drain temperature temperature measurement.measurement.


Oil Flow ObservationOil Flow Observation

““QuickQuick”” indication as to indication as to the operation of the the operation of the bearing through the bearing through the drain line (temperature drain line (temperature and flow), nonetheless and flow), nonetheless reveals little of the reveals little of the health of the bearing.health of the bearing.


General Bearing StartGeneral Bearing Start

MetalMetal--toto--metal Contactmetal Contact

Boundary LubricationBoundary Lubrication

Hydrodynamic Hydrodynamic LubricationLubrication

H < 0.0005H < 0.0005””

H > 0.0005H > 0.0005””


Bearing Start/ShutdownBearing Start/Shutdown

Ref. Ref. BasicsBasics, , NoriaNoria, Johnson, , Johnson, 20012001




Hydrostatic Lift SystemsHydrostatic Lift Systemsnn Installed to provide hydrostatic oil Installed to provide hydrostatic oil

films where hydrodynamic oil films films where hydrodynamic oil films may not otherwise be presentmay not otherwise be presentnnStart up operationStart up operationnnTurning gear operationTurning gear operationnnSome emergency conditionsSome emergency conditionsnnPer DIN 31652 part 3 consider Per DIN 31652 part 3 consider

hydrostatic lift where startup loads hydrostatic lift where startup loads exceed 2.5exceed 2.5--3.0 3.0 MPaMPa (363(363--435 435 psipsi))nnMay be required for lower loadsMay be required for lower loads


Hydrostatic Lift SystemsHydrostatic Lift Systemsnn Inject high pressure oil (typically > Inject high pressure oil (typically >

1000 1000 psipsi) at the location of the ) at the location of the highest loadinghighest loading

nnHydrostatic film is developed Hydrostatic film is developed through pressure, film thickness is through pressure, film thickness is controlled by flowcontrolled by flow

nnQuite often, many bearings are fed Quite often, many bearings are fed by a common high pressure headerby a common high pressure header


Hydrostatic Lift SystemHydrostatic Lift Systemnn Introduce externallyIntroduce externally--pressurized oil pressurized oil

into bearing cavity for operation at into bearing cavity for operation at low surface speeds and high loadslow surface speeds and high loadsnn Forms hydrostatic bearing on lower halfForms hydrostatic bearing on lower half


Hydrostatic Lift SystemHydrostatic Lift System

Hydrostatic lift in tilting pad thrust shoes.Hydrostatic lift in tilting pad thrust shoes.


Main oil pump is shaft drivenMain oil pump is shaft driven

AC & DC pumpsAC & DC pumps

Sample Hydrostatic Lift Oil SystemSample Hydrostatic Lift Oil System

Schematic of Schematic of TurbineTurbine--Generator Generator Hydrostatic Hydrostatic Lift SystemLift System

Each radial bearing #3Each radial bearing #3--8 has a 8 has a separate pressurized hydrostaticseparate pressurized hydrostatic--lift supply (1500 psig), separate lift supply (1500 psig), separate supply pump with a gravity (or supply pump with a gravity (or slight vacuum) drain back to the slight vacuum) drain back to the reservoir.reservoir.


Bearing DesignBearing DesignnnPhysical / mathematical model Physical / mathematical model

used to define the characteristics of used to define the characteristics of the fluidthe fluid--film (possibly with film (possibly with supporting components) in the supporting components) in the bearing geometry.bearing geometry.

nnGeneral evaluation based on key General evaluation based on key design parametersdesign parameters




Specific LoadSpecific Loadnn Gives a measure of the load on the Gives a measure of the load on the

bearingbearingnn Based on Nominal Load (Based on Nominal Load (psipsi).).

Thrust,Thrust,

Radial,Radial,

nn Not the same as the peak pressure (Not the same as the peak pressure (psipsi))

P WOD ID

=−

π4

2 2

P WL D

=⋅


Specific LoadSpecific LoadnnRadial bearing loadsRadial bearing loadsnnMaximum load capacityMaximum load capacity

nn300 300 psipsi radial (American)radial (American)nn5 5 MPaMPa (725 (725 psipsi) radial (European)) radial (European)nn500 500 -- 700 700 psipsi thrustthrust

nnMinimum load for stability with some Minimum load for stability with some bore designs (10 bore designs (10 psipsi –– 50 50 psipsi))


Nominal versus Actual PressureNominal versus Actual Pressure

Actual peak Actual peak pressure will pressure will exceed the nominal exceed the nominal pressure.pressure.


Surface SpeedSurface SpeednnMeasure of heat generationMeasure of heat generationnn Based on peripheral speed (ft/min).Based on peripheral speed (ft/min).

Thrust,Thrust,

Radial,Radial,

Limits due to turbulent heat generation.Limits due to turbulent heat generation.

U OD ID N=+π

12 2( )

U D N=⋅π

12


Surface SpeedSurface Speednn Increasing speed allowed for Increasing speed allowed for

different bore designsdifferent bore designsnnSleeve: 30 Sleeve: 30 m/sm/s ( 98 ft/s)( 98 ft/s)nnElliptical: 75 Elliptical: 75 m/sm/s (240 ft/s)(240 ft/s)nn44--Lobed: 125 Lobed: 125 m/sm/s (410 ft/s)(410 ft/s)nnTilting pad: 150 Tilting pad: 150 m/sm/s (492 ft/s)(492 ft/s)nnMotors, fans, compressors, turbinesMotors, fans, compressors, turbines

Ref: Ref: RenkRenk Slide Bearing design guide Slide Bearing design guide


Clearance RatioClearance RationnExpresses the radial bore clearance Expresses the radial bore clearance

as a ratio of the journal diameteras a ratio of the journal diameter

nnHorizontal machinesHorizontal machinesnnPressurized: 1.5 Pressurized: 1.5 –– 2.0 mils/in2.0 mils/innnSlinger rings: 2.0 Slinger rings: 2.0 –– 2.5 mils/in2.5 mils/in

nnVertical machinesVertical machinesnn0.5 0.5 –– 1.0 mils/in1.0 mils/in

DCd

=Ψ




Minimum Design ClearanceMinimum Design Clearance

Ref. Ref. NealeNeale, , BearingsBearings, , Butterworth Butterworth HeinemanHeineman, , 1998, pg. 39.1998, pg. 39.


Sommerfeld NumberSommerfeld Numbernn American Standard American Standard -- Radial.Radial.

S N D LW

DCd

= ⋅ ⋅ ⋅ ⋅

µ2

S UD P

= ⋅ ⋅⋅ ⋅ ⋅µ

π ψ1 2

2

DCd

=Ψ

DLWP =

µµ –– viscosityviscosity

N N –– rotating speed (Hz)rotating speed (Hz)

U U –– surface speedsurface speed


Bearing DesignBearing DesignnnMain Considerations:Main Considerations:nnPeak temperaturePeak temperature

nnMinimum film thicknessMinimum film thicknessnnOn the order of 0.001On the order of 0.001””

nnDesign by Empiricism and Detailed Design by Empiricism and Detailed Analysis.Analysis.

∆T LossesJ c Qtotaloil

v=

⋅ ⋅ ⋅ρ

Losses include oil Losses include oil shear, churning, oil shear, churning, oil pumping, and process pumping, and process heatingheating


Heat TransferHeat TransferRatio of conduction to convection is Ratio of conduction to convection is proportional to:proportional to:

≈ 2

2UhB

CpKratioρ

Where,Where,

KK--thermal conductivitythermal conductivity

ρρ--densitydensity

CpCp--specific heatspecific heat

κκ=K/=K/ρρCpCp –– thermal diffusivitythermal diffusivity

BB--0.5*0.5*ππ*D*D

UU--surface velocitysurface velocity

HH--average film thicknessaverage film thickness

Ref: Cameron, Ref: Cameron, Basic LubricationBasic Lubrication, pg 127., pg 127.


Design Space LimitsDesign Space Limits

Ref. Ref. NealeNeale, , BearingsBearings, , Butterworth Butterworth HeinemanHeineman, , 1998, pg. 38.1998, pg. 38.

A A –– load limitload limit

B B –– temperature limittemperature limit

C C –– material burst material burst speedspeed

AA

BB

CC


SummarySummarynn Radial bearingsRadial bearings

nnBore designBore designnnOptimum load Optimum load –– sleevesleevennOptimum stability Optimum stability –– tilt padtilt pad

nn Thrust bearingsThrust bearingsnn Profile designsProfile designsnnOptimum load Optimum load –– tilt padtilt pad

nn FluidFluid--film bearing analysisfilm bearing analysisnn Reynolds equationReynolds equationnnCavitationCavitation




EndEnd

Bearing Bearing Fundamentals IIFundamentals II

May 2006

Interface with Predictive Maintenance Programs Sheet 1

(c) Pioneer Motor Bearing Company, 2006.

Interface with Predictive Interface with Predictive Maintenance ProgramsMaintenance Programs


PIONEER FLUIDPIONEER FLUID--FILM BEARING WORKSHOPFILM BEARING WORKSHOP


OutlineOutlinenn Vibration monitoringVibration monitoringnn Lubricant monitoringLubricant monitoringnn Temperature monitoringTemperature monitoringnn ThermographyThermographynn BalancingBalancing


Types of AlarmsTypes of AlarmsnnProtection / AgingProtection / AgingnnStatisticalStatisticalnnGoal basedGoal based


Monitoring PurposesMonitoring PurposesnnAvoid Avoid ““absoluteabsolute”” levels at which levels at which

damage is expecteddamage is expectednnExample: Prevent high temperature at Example: Prevent high temperature at

which bearing material can no longer which bearing material can no longer support the applied load.support the applied load.

nnDetect changes in the machine Detect changes in the machine based on trendingbased on trendingnnExample: Identify step increase in Example: Identify step increase in

vibration level over time.vibration level over time.


Machine MonitoringMachine Monitoring

Ref: Mitchell, Ref: Mitchell, MachinerMachiner MonitoringMonitoring

Vibration Vibration monitoring monitoring at or near at or near the the bearingsbearings


Vibration MonitoringVibration MonitoringVibration Vibration is the is the product product of the of the excitationexcitation(force(force) ) with the with the machine machine system system (transfer (transfer function). function). Must Must know two know two out of out of three.three.

Ref. Ref. EhrichEhrich, , Handbook of Handbook of RotordynamicsRotordynamics, p.4.54, p.4.54..

May 2006



Vibration MonitoringVibration Monitoring

Common vibration Common vibration frequency content frequency content with malfunctions.with malfunctions.

Ref. Ref. EhrichEhrich, , Handbook of Handbook of RotordynamicsRotordynamics, p.4.55, p.4.55--4.564.56..


Vibration MonitoringVibration Monitoring

NonNon--linear linear vibration vibration responses.responses.

Ref. Ref. EhrichEhrich, , Handbook of Handbook of RotordynamicsRotordynamics, p.4.60, p.4.60..


Shaft Relative to Casing MeasurementShaft Relative to Casing Measurement

Useful for monitoring where the primary shaft motion is within tUseful for monitoring where the primary shaft motion is within the he bearing (consider the relative stiffness of the oil film and thebearing (consider the relative stiffness of the oil film and the bearing bearing support). Also, can compare motion to the expected bearing support). Also, can compare motion to the expected bearing clearance.clearance.


Mounting ConsiderationsMounting Considerations

Ref: SKF web site, 04/06.Ref: SKF web site, 04/06.

Mounting internal Mounting internal to the bearingto the bearing

Impact on Impact on bearing bearing load load capacity?capacity?

Mounting external to the bearingMounting external to the bearing

Impact on vibration limits?Impact on vibration limits?


Flexibility Effect on MonitoringFlexibility Effect on Monitoring


Include Casing MeasurementInclude Casing Measurement

May 2006



Frequency ContentFrequency Content

Looseness:Looseness:

Ground CurrentsGround Currents

Primary frequency content associated Primary frequency content associated with fluidwith fluid--film bearings is film bearings is synchronous (1X). Other frequencies synchronous (1X). Other frequencies may occur due to different causes.may occur due to different causes.

SubsynchronousSubsynchronous whirlwhirl

SubsynchronousSubsynchronous whipwhip

MisalignmentMisalignment


Allowable Vibration LevelsAllowable Vibration LevelsnnAbsolute limitsAbsolute limitsnnGenerally based on experienceGenerally based on experiencennLimit to a fraction of the bearing Limit to a fraction of the bearing

clearance (e.g. 50%)clearance (e.g. 50%)nnBearing limits generally not controllingBearing limits generally not controlling

nnContact at sealsContact at sealsnnExcessive loadsExcessive loads


Bearing Loads AffectedBearing Loads AffectednnConditions determined by vibration Conditions determined by vibration

analysis which have an impact on analysis which have an impact on bearing loadsbearing loadsnnStaticStaticnnDynamicDynamic


Bearing Loads AffectedBearing Loads Affected

Misalignment Misalignment -- static load static load variationvariationSoft Foot Soft Foot –– dynamic load variationdynamic load variation

Imbalance Imbalance –– dynamic loads on bearingsdynamic loads on bearings


Lubricant MonitoringLubricant MonitoringnnViscosity MonitoringViscosity MonitoringnnNote that baseline oil will vary within Note that baseline oil will vary within

the standardthe standardnnLook for changes around +/Look for changes around +/-- 10% from 10% from

baselinebaseline

nnOil Degradation Oil Degradation nnWear MaterialsWear Materials


Lubricant MonitoringLubricant MonitoringnnRequires careful samplingRequires careful samplingnnRepresentative of the bulk oilRepresentative of the bulk oil

nnSampling pointSampling pointnnMaintain cleanlinessMaintain cleanlinessnnConsistent handlingConsistent handling

nnAuxiliary bearing oil reservoirs may Auxiliary bearing oil reservoirs may be smallbe smallnnSampling assumes reservoir is much Sampling assumes reservoir is much

larger than the samplelarger than the sample

May 2006



Lubricant DegradationLubricant Degradation

Shows Shows scatter of scatter of RBOT testing RBOT testing for a single for a single oil and effect oil and effect of operation of operation of 18 years of 18 years and 21 years and 21 years on two on two particular particular oils.oils.


Metals in OilMetals in Oilnn Various metals included in additivesVarious metals included in additives

nnBoron (B)Boron (B)nnCalcium (Ca)Calcium (Ca)nnMagnesium (Mg)Magnesium (Mg)nnBarium (Barium (BaBa))nnMolybdenum (Mo)Molybdenum (Mo)nn Phosphorus (P)Phosphorus (P)

nn Concern w/catalytic converter (may change by 04/04)Concern w/catalytic converter (may change by 04/04)

nn Potassium (K)Potassium (K)nn Zinc (Zn)Zinc (Zn)nn Antimony (Antimony (SbSb))


Metals in OilMetals in OilnnMetals from bearingMetals from bearingnnBabbitt (tin based)Babbitt (tin based)

nnTinTinnnAntimonyAntimonynnCopperCopper

nnSlinger rings (bronze)Slinger rings (bronze)nnCopperCoppernnTin / ZincTin / Zinc

nnJournal / Shell (steel)Journal / Shell (steel)nn IronIron

Wide range of Wide range of possible babbitt possible babbitt wear particle wear particle sizes. Many sizes. Many detection detection methods in oil methods in oil analysis are size analysis are size dependent.dependent.


Metals from BearingMetals from Bearingnn Babbitt wipingBabbitt wiping

nn Large platelets Large platelets –– may not be detectedmay not be detected

nn Babbitt fatigueBabbitt fatiguenn Large pieces Large pieces –– may not be detectedmay not be detected

nn ElectrolysisElectrolysisnn Smaller particles Smaller particles –– more likely to be detectedmore likely to be detected

nn Slinger ring abrasive/adhesive wearSlinger ring abrasive/adhesive wearnnOne plant takes action around 30One plant takes action around 30--100 100 ppmppm

of copper (Cu)of copper (Cu)


Particle DetectionParticle DetectionnnDetection by many spectroscopic Detection by many spectroscopic

techniquestechniquesnnParticles smaller than 5 micronsParticles smaller than 5 microns


Lubricant CleanlinessLubricant CleanlinessnnMeasured by particle countingMeasured by particle countingnn““RepresentativeRepresentative”” samplesamplennReported based on particle size and Reported based on particle size and

concentrationconcentrationnnCurrent standard: RCurrent standard: R44/R/R66/R/R1414

nnOlder standard: ROlder standard: R55/R/R1515

nnLimits set by critical componentLimits set by critical componentnnControl surface or valves, bearingControl surface or valves, bearingnnOEM limits: 16/12, 16/13, 15/12OEM limits: 16/12, 16/13, 15/12

May 2006



Contamination from Oil SystemContamination from Oil System

Ref. Ref. NoriaNoria presentation materialpresentation material


Grease ContaminationGrease ContaminationnnContamination of oil from adjacent Contamination of oil from adjacent

grease lubricated systemgrease lubricated systemnnIncrease in particle countIncrease in particle count

nnWithout increase in wear particlesWithout increase in wear particles

nnReduction in viscosity is possibleReduction in viscosity is possiblennDue to the gelling agentDue to the gelling agentnnNot the base oil which is typically more Not the base oil which is typically more

viscousviscous


Lubricant DegradationLubricant Degradationnn Base oil has finite life due to onBase oil has finite life due to on--going going

oxidationoxidationnnCatalyzed in copper pipingCatalyzed in copper pipingnnCatalyzed by water in the oilCatalyzed by water in the oil

nn Additive depletionAdditive depletionnn Reduction of antiReduction of anti--oxidantoxidant

nn Base oil burned at hot spotsBase oil burned at hot spotsnn Base oil changesBase oil changesnn Increasing viscosityIncreasing viscositynn Sludge and varnishSludge and varnish

Oil degradation Oil degradation rate doubles rate doubles with every 18with every 18°°F F rise in bulk oil rise in bulk oil temperature.temperature.


Temperature MonitoringTemperature MonitoringnnLimitsLimitsnnJournal bearingsJournal bearingsnnThrust bearingsThrust bearings


Temperature LimitsTemperature Limitsnn ISSUESISSUESnnMeasurement locationMeasurement location

nnHow close to the hottest metal location?How close to the hottest metal location?

nnLoadLoadnnBabbitt strength is dependent on Babbitt strength is dependent on

temperaturetemperaturennHeavy load regions will move firstHeavy load regions will move first

nnThermal distortionThermal distortionnnChanges in film thickness distribution that Changes in film thickness distribution that

reduce load capacityreduce load capacity


Absolute / RelativeAbsolute / Relativenn Absolute limitsAbsolute limits

nn Require knowledge of design details, loads, Require knowledge of design details, loads, and speedsand speeds

nnGenerally a predictive effortGenerally a predictive effortnn Possibly relating a peak temperature to a measured Possibly relating a peak temperature to a measured

pointpoint

nn Relative limitsRelative limitsnn Requires historical temperature informationRequires historical temperature informationnn Looking for deviation from a normLooking for deviation from a norm

nn Can be complicated by normal operating variationsCan be complicated by normal operating variations

nn ““Rules of thumbRules of thumb””nnGuidelines to initiate relative monitoring in Guidelines to initiate relative monitoring in

the absence of predictive informationthe absence of predictive information

May 2006



Temperature LimitsTemperature LimitsnnConsidering Babbitt (not Lubricant)Considering Babbitt (not Lubricant)nnNominal bearing loading.Nominal bearing loading.nnRequires accurate measure of peak Requires accurate measure of peak

temperature.temperature.nnAlloy #2.Alloy #2.

APPLICATION ALARM TRIP ReferenceSteam / gas turbine 225°F (107°C) 250°F (121°C) GlacierTilt pads 230°F 250°F (121°C) NicholasKEPCO (95-100°C) (120°C)No load 300°F (149°C) GlacierTrident sub gear bearing 300°F

nn Actual temperature also controlled by Support Material, Oil Actual temperature also controlled by Support Material, Oil Flow Path, and Oil Volume.Flow Path, and Oil Volume.


Lubricant Temperature LimitsLubricant Temperature LimitsnnLoss of Viscosity.Loss of Viscosity.nnDue to temperature or oxidation.Due to temperature or oxidation.

nnMaterial Degradation.Material Degradation.nnOxidation.Oxidation.nnVarnishing.Varnishing.nnLoss of additives.Loss of additives.nnActivated by corrosion.Activated by corrosion.


Temperature ProfilesTemperature Profiles

Case 1: Peak Case 1: Peak TemperatureTemperature

Case 2: Case 2: Peak Peak TemperaturTemperaturee

Angular Location from Start of Angular Location from Start of FilmFilm

SAME Drain SAME Drain TemperatureTemperature


Journal Bearing MeasurementJournal Bearing MeasurementnnThermocouple or RTD (100Thermocouple or RTD (100°°FF--

250250°°F).F).nnLocation.Location.nnCircumferential Circumferential -- 75% offset from 75% offset from

leading edge.leading edge.nnAxial Axial -- centered or symmetric pair.centered or symmetric pair.nnRadial Radial -- retain support for babbitt retain support for babbitt

above sensor.above sensor.

nnWiring.Wiring.nnAvoid impeding pad tilt or oil flow.Avoid impeding pad tilt or oil flow.


Temperature MeasurementTemperature MeasurementOptions for thermocouples Options for thermocouples or RTDor RTD’’s.s.


Mounting LocationsMounting Locations

May 2006



Tilting Pad Journal BearingsTilting Pad Journal Bearings

Flooded design: sump (drain) Flooded design: sump (drain) temperature is an average of the temperature is an average of the circulating oil temperature and circulating oil temperature and can be directly lowered by can be directly lowered by increasing flow.increasing flow.

Directed lubrication (Fluid Directed lubrication (Fluid PivotPivot®®) with direct ) with direct measurement of bearing measurement of bearing metal temperature.metal temperature.


Thrust Bearing TemperaturesThrust Bearing Temperatures


Thrust Bearing MeasurementThrust Bearing MeasurementnnThermocouple or RTD (100Thermocouple or RTD (100°°FF--

250250°°F).F).nnLocation.Location.nn75%/75% Tilt pad.75%/75% Tilt pad.nn 70%/70% Circumferential/Radial.70%/70% Circumferential/Radial.nn50%/50% Circumferential/Radial.50%/50% Circumferential/Radial.nnAxial Axial -- retain support for babbitt above retain support for babbitt above

sensor.sensor.nnWiring.Wiring.nnAvoid impeding pad tilt or oil flow.Avoid impeding pad tilt or oil flow.


Thrust Bearing MeasurementThrust Bearing Measurement

Ref: Mitchell, Ref: Mitchell, MachineryMachinery

*** Standard * Standard monitoring monitoring location for one location for one OEM OEM


Mounting LocationsMounting Locations


ThermographyThermographynnGives an overview of the Gives an overview of the

temperature over accessible temperature over accessible portions of the housing, shaft, and portions of the housing, shaft, and bearing.bearing.

nnNeed to understand the relationship Need to understand the relationship between the measured locations between the measured locations and the hottest operating parts of and the hottest operating parts of the bearingthe bearing

May 2006



ThermographyThermographyConsider the likely Consider the likely temperature gradient temperature gradient from the peak bearing from the peak bearing babbitt temperature babbitt temperature to the motor casing to the motor casing temperature. Note temperature. Note circumferential and circumferential and axial spreading of the axial spreading of the ““hot spothot spot””..


BalancingBalancingnn Balancing calculation is generally Balancing calculation is generally

determined by thedetermined by thennCurrent vibration level at the bearingsCurrent vibration level at the bearingsnn Influence of a weight at each balance planeInfluence of a weight at each balance plane

nn Vibration level changesVibration level changesnnBearing changes orBearing changes ornn Imbalance changes?Imbalance changes?

nn Influence of balance weightsInfluence of balance weightsnnBased on the dynamics of the rotor supportBased on the dynamics of the rotor support

nn Based on the bearing geometry and conditionBased on the bearing geometry and condition


OutlineOutlinenn Consider effect of bearing design and Consider effect of bearing design and

operation on the tools in your Predictive operation on the tools in your Predictive Maintenance programMaintenance programnnVibration monitoringVibration monitoringnnLubricant monitoringLubricant monitoringnnTemperature monitoringTemperature monitoringnnThermographyThermographynnBalancingBalancing

Rotor change or Rotor change or bearing change or bearing change or …… ??


EndEnd

Preventative MaintenancePreventative MaintenanceInterfaceInterfaceSectionSection

August 2004

Installation and Handling Sheet 1

Copyright 2006, Pioneer Motor Bearing Company

Installing and HandlingInstalling and Handlingof of BabbittedBabbitted BearingsBearings(partial)(partial)



OutlineOutlinenn Abbreviated presentation with emphasis on Abbreviated presentation with emphasis on

potential impact on machine vibrations:potential impact on machine vibrations:nn Visual InspectionVisual Inspectionnn MeasurementsMeasurementsnn Alignment ConsiderationsAlignment Considerationsnn Pedestal MeasurementsPedestal Measurementsnn ScrapingScrapingnn Shaft RoughnessShaft Roughnessnn Cleanliness RequirementsCleanliness Requirementsnn Material Handling RequirementsMaterial Handling Requirementsnn NDE RequirementsNDE Requirementsnn InsulationInsulationnn Final Assembly TipsFinal Assembly Tips


Visual InspectionVisual InspectionnnVisually inspect bearings and Visually inspect bearings and

associated hardware for damageassociated hardware for damagennRefer to the bearing damage section Refer to the bearing damage section

of this presentation for assistance of this presentation for assistance with root cause analysiswith root cause analysis

nn It is never a great idea to reIt is never a great idea to re--assemble assemble any machinery with bearings that are any machinery with bearings that are visibly damaged visibly damaged


Journal DiameterJournal DiameternnMeasure for diameter, taper, and Measure for diameter, taper, and

ellipticityellipticitynnMeasure within 0.0002Measure within 0.0002””nn Should be round within 0.0005Should be round within 0.0005””nn Taper less than 0.0005Taper less than 0.0005””/inch of length/inch of length

nn Uniform taper less critical with dynamically Uniform taper less critical with dynamically aligning radial bearingaligning radial bearing

nn Be aware that any eccentricity from the Be aware that any eccentricity from the journal to the rest of the rotor can journal to the rest of the rotor can appear as higher dynamic forcesappear as higher dynamic forces


Bore diameterBore diameter

AA

BB

CC

DD

EE

5EDCBA ++++

=φ

Measure 5 Measure 5 diameters.diameters.

Circular boreCircular bore

Elliptical boreElliptical bore

DB

EAC

Horizontal

Vertical

=

+≈

=

2φ

φ

Repeat measurements near front and back Repeat measurements near front and back axial faces to check for taper.axial faces to check for taper. Copyright 2006, Pioneer Motor Bearing Company

Outer diameterOuter diameter

EE

EEAA

AA

BB

BB

CC

CC

DD

DD

Repeat Repeat measuremeasure--mentsmentsnear front near front and back and back axial axial faces to faces to check for check for taper.taper.

August 2004



Pad thicknessPad thickness

AA

BB

CC

DDEE

Measure wall Measure wall thickness near thickness near both axial faces both axial faces (check taper) and (check taper) and on each pad on each pad (check (check consistency).consistency).

Preloaded pad Preloaded pad has thicker has thicker crown (C) than crown (C) than ends (A,E).ends (A,E).


Tapered Thrust PlateTapered Thrust PlateCCW rotationCCW rotation

Measure drop Measure drop with respect to with respect to flat land region flat land region at 15 at 15 ““circledcircled””points, as points, as indicated.indicated.CROSSCROSS--SECTIONSECTION


Thrust Bearing ClearancesThrust Bearing Clearancesnn Axial range of motion of the shaft Axial range of motion of the shaft

between between ““activeactive”” and and ““inactiveinactive”” thrust thrust surfaces.surfaces.

nn Field checked by bump testField checked by bump testnnMust overcome residual oil filmsMust overcome residual oil films

nn Clearance can increase due to Clearance can increase due to component compressioncomponent compressionnn Leveling linksLeveling linksnn Shim packs or supportsShim packs or supports

nn Clearance can decrease due to shaft Clearance can decrease due to shaft expansionexpansion


Thrust Bearing ClearancesThrust Bearing Clearancesnn Usually Adjusted through the use of a Usually Adjusted through the use of a

shim or filler plateshim or filler platenn AvoidAvoid the use of numerous stacked shimsthe use of numerous stacked shimsnn Calculate the required shim thickness Calculate the required shim thickness

using measurements of available spaceusing measurements of available spacenn Thickness of tilting pad thrust bearings Thickness of tilting pad thrust bearings

must be measured as an assemblymust be measured as an assemblynn Confirm final clearance by bump checking Confirm final clearance by bump checking

rotor with upper housing half in placerotor with upper housing half in place


Alignment ConsiderationsAlignment ConsiderationsnnReview historical operational dataReview historical operational datannReview OEM recommendationsReview OEM recommendationsnnMeasure and document as found Measure and document as found

conditionsconditions


Bearing ElevationBearing ElevationnnMultiple bearings (>2) for a continuous Multiple bearings (>2) for a continuous

shaftshaftnn Typical power generation shaftsTypical power generation shaftsnnGoal: Goal: ““eveneven”” loading by setting proper loading by setting proper

elevation and alignment of each bearingelevation and alignment of each bearing

nn Typical elevation follows Typical elevation follows catenarycatenary curvecurvenn Avoids adding additional shaft momentAvoids adding additional shaft moment

nn Installation may need to Installation may need to ““preloadpreload””bearing to set at the proper elevationbearing to set at the proper elevation

August 2004



CatenaryCatenary CurveCurve

= amptampty cosh)(

Applies to Applies to hanging hanging chain, chain, power line, power line, rope, etc.rope, etc.


CatenaryCatenary CurveCurveBearing Bearing installation installation seeks to seeks to place all place all bearings on bearings on a caternary a caternary curve.curve.


CatenaryCatenary CurveCurve

Ref. Ref. ““Bearing Bearing MisalignmentMisalignment……500MW 500MW TurboGeneratorTurboGenerator””, Ettles, et , Ettles, et al, 1974.al, 1974.

0 20 40 60 80 100 120 140 1600.5

0

0.5

1

1.5Catenary Curve: Designed vs As-Built

Axial Position from #1 Bearing (in)

Gra

vity

Sag

(in)

1.35

0.121−

catin

catFoundin

1520 axialft

>1.2>1.2””

500 MW turbine generator, 150 ft long, 14 bearings500 MW turbine generator, 150 ft long, 14 bearings

CatenaryCatenary curve curve minimizes bearing minimizes bearing loads and moments.loads and moments.


CatenaryCatenary CurveCurvennRaise bearing from shaft sag Raise bearing from shaft sag

position to desired point on the position to desired point on the catenarycatenary curve.curve.

SagSag

Operating Operating catenarycatenary curvecurve

Main BearingMain Bearing Overhung BearingOverhung Bearing

Setting elevation of Setting elevation of end bearing (e.g. end bearing (e.g. exciter)exciter)

““PreloadPreload””


Elevation PreloadElevation Preloadnn Raise bearing from shaft sag position Raise bearing from shaft sag position

above desired point on the above desired point on the catenarycatenarycurve to improve stability of sleeve curve to improve stability of sleeve bearing.bearing.

Setting elevation of end Setting elevation of end bearing (e.g. exciter)bearing (e.g. exciter)

SagSag

Operating Operating catenarycatenary curvecurve

Main BearingMain Bearing Overhung BearingOverhung Bearing

PreloadPreload

Additional bearing elevationAdditional bearing elevation


Bearing AdjustmentBearing AdjustmentnnQuite often, when installing new or Quite often, when installing new or

rebuilt bearings will require rebuilt bearings will require alignment of the machineryalignment of the machinery

nnMany large turbine and generator Many large turbine and generator bearings have alignment bearings have alignment ““KeysKeys””installedinstalled

nnMany smaller machines require Many smaller machines require adjustment of the bearing housing adjustment of the bearing housing or pedestalor pedestal

August 2004



Bearing AdjustmentBearing Adjustment

Typical Tilting Pad Journal Bearing with external Typical Tilting Pad Journal Bearing with external ““KeysKeys”” for adjusting the radial position of the bearingfor adjusting the radial position of the bearing



Lower Bearing half with adjustment keys centeredLower Bearing half with adjustment keys centered



Adjustment of keys for horizontal offset showing improper contacAdjustment of keys for horizontal offset showing improper contact t with the housing borewith the housing bore


MisalignmentMisalignmentnnRadial: journal axial centerline is Radial: journal axial centerline is

not parallel to the bearing not parallel to the bearing centerline.centerline.

nnThrust: runner surface is not Thrust: runner surface is not parallel to the bearing surface.parallel to the bearing surface.


Misalignment AccommodationMisalignment Accommodationnn Goal: Prevent unGoal: Prevent un--even loading of bearingeven loading of bearingnn Especially edgeEspecially edge--loadingloading

nn RadialRadialnn Spherical, Spherical, ““ball fitball fit”” on OD (outer diameter)on OD (outer diameter)nn Spherical (e.g. Spherical (e.g. ““ball in socketball in socket””) surface for ) surface for

pad OD in tiltpad OD in tilt--pad bearingpad bearingnnOther means of aligning: scraping, pins, Other means of aligning: scraping, pins,

shimsshimsnn ThrustThrustnn Leveling linksLeveling linksnn Spherical fit on thrust plate backSpherical fit on thrust plate backnnOther means: pins, shimsOther means: pins, shims


Misalignment AccommodationMisalignment Accommodation

Blue Check of Turbine Journal BearingBlue Check of Turbine Journal Bearing

August 2004



Alignment IssuesAlignment IssuesnnGenerally installed under cold Generally installed under cold

conditionsconditionsnnAlignment varies with temperatureAlignment varies with temperaturennAffected by casing distortionsAffected by casing distortions

nnMechanical fits can Mechanical fits can ““lock uplock up”” under under operating bearing (radial or thrust) operating bearing (radial or thrust) loadsloadsnnPrevents further adjustmentPrevents further adjustmentnnProblem installations require nonProblem installations require non--

mechanical accommodationmechanical accommodation


Bearing Support FitsBearing Support FitsnnHousingsHousingsnnClearance fits / Tight fitsClearance fits / Tight fits

nnDepends on housing design and bearing Depends on housing design and bearing wall thicknesswall thickness

nnPedestalPedestalnnAvoid Avoid ““softsoft”” footfoot

nnNo deflection > 0.001No deflection > 0.001””

nnConsequence of loosenessConsequence of loosenessnnReduced stiffness and dampingReduced stiffness and dampingnnIncreased vibrationIncreased vibration


Thrust Collar Thrust Collar RunoutRunoutnn Want the collar Want the collar ““squaresquare”” to the axis of rotationto the axis of rotation

nn Avoid collar Avoid collar ““wobblewobble””nn Can be difficult to measure if shaft is floating on Can be difficult to measure if shaft is floating on

the radial bearingsthe radial bearingsnn Dial indicators 180Dial indicators 180°° apartapart

nn A and B indicatorsA and B indicatorsnn Record the measurements as the shaft is turned at Record the measurements as the shaft is turned at

both indicatorsboth indicatorsnn Sign of the reading (+ or Sign of the reading (+ or --) must be recorded) must be recorded

nn Insure that both indicators return to Insure that both indicators return to ““zerozero””nn Subtract readings at Subtract readings at ““BB”” from from ““AA””nn Gives Gives twicetwice the TIR of the collarthe TIR of the collar


Material Handling Material Handling RequirementsRequirementsnnAvoid excessive forceAvoid excessive forcennUse secure jacking systems to Use secure jacking systems to

support shaft during and after support shaft during and after bearing removalbearing removal

nn If using an overhead crane, roll the If using an overhead crane, roll the bearing using bearing using chainfallschainfalls, not the , not the main or auxiliary hookmain or auxiliary hook


Material Handling Material Handling RequirementsRequirementsBearings will gall and pick up metal Bearings will gall and pick up metal from the pedestal bore if excessive from the pedestal bore if excessive force is used for installation or force is used for installation or removal.removal.Caution must be exercised while Caution must be exercised while installing or removing bearings. installing or removing bearings. Fingers should never be inserted in Fingers should never be inserted in barring holes or between lifting barring holes or between lifting eyes and the pedestal joint. It is eyes and the pedestal joint. It is quite a common occurrence that a quite a common occurrence that a bearing that seems tightly wedged bearing that seems tightly wedged in position will quickly roll to in position will quickly roll to bottom dead center with great bottom dead center with great force. force.


Bearing InsulationBearing Insulationnn Insulation serves as a electrical Insulation serves as a electrical

boundaryboundarynn Humidity will degrade insulationHumidity will degrade insulationnn Insulation resistance lowers with Insulation resistance lowers with

temperaturetemperaturenn Oily dirt and debris will degrade Oily dirt and debris will degrade

insulationinsulation

nn Insulation serves as a Insulation serves as a mechanical boundarymechanical boundarynn Prevent dirt from Prevent dirt from ““bridgingbridging”” the the

insulationinsulationnn Avoid damaging due to impact or Avoid damaging due to impact or

peeling.peeling.

August 2004



Bearing InstallationBearing Installation

nn Thin wall shellsThin wall shellsnn Precision halves conform to housingPrecision halves conform to housingnnBearing geometry depends on housing Bearing geometry depends on housing

geometrygeometrynn Shell must conform to housing geometryShell must conform to housing geometry

nn Thick wall shellsThick wall shellsnnBearing defines geometryBearing defines geometrynnHousing supports bearingHousing supports bearing

nn Distortion from housing is undesirableDistortion from housing is undesirable


Assembly TipsAssembly Tips

nnKeep area clean, so as not to Keep area clean, so as not to drop any foreign material into drop any foreign material into the bearing during reassemblythe bearing during reassembly

nnClean joint facesClean joint facesnnJoint faces should be tight Joint faces should be tight

within 0.001within 0.001””nnAvoid striking or scratching Avoid striking or scratching

babbitt surfacebabbitt surfacennAvoid overuse of gasket cement Avoid overuse of gasket cement

around the pedestal cap jointsaround the pedestal cap joints


EndEnd

Installing and Handling Installing and Handling Bearings (partial)Bearings (partial)

introduction may 2006june 2004 outline - vibration 2006/fluid film... · ·...

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