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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
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
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 (c) Pioneer Motor Bearing Company, 2006
LocationsLocations
California:California:AdministrationAdministration& Regional Sales& Regional Sales
Philadelphia:Philadelphia:TechnicalTechnicalServicesServices
North Carolina:North Carolina:
EngineeringEngineeringManufacturingManufacturingService & RepairService & Repair
Introduction May 2006June 2004
(c) Pioneer Motor Bearing CompanyIntroduction Sheet 2
(c) Pioneer Motor Bearing Company, 2006
Pioneer Motor BearingPioneer Motor Bearing
Engineering
Manufacturing Service & Repair(c) Pioneer Motor Bearing Company, 2006
(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
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
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
Introduction May 2006June 2004
(c) Pioneer Motor Bearing CompanyIntroduction Sheet 3
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
DemonstrationsDemonstrationsnnViscosityViscositynnHydrodynamic filmHydrodynamic filmnnCavitationCavitationnnSlinger ring operationSlinger ring operation
Introduction May 2006June 2004
(c) Pioneer Motor Bearing CompanyIntroduction Sheet 4
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
A A ““smallsmall”” piece in the plantpiece in the plant
(c) Pioneer Motor Bearing Company, 2006
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:
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006
Lubricant PerspectiveLubricant PerspectivennLubricant to satisfy requirementsLubricant to satisfy requirementsnnViscosityViscositynnProper additivesProper additives
nnAdequate operational lifeAdequate operational lifennUnderstand impact on oil analysisUnderstand impact on oil analysis
(c) Pioneer Motor Bearing Company, 2006
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
Introduction May 2006June 2004
(c) Pioneer Motor Bearing CompanyIntroduction Sheet 5
(c) Pioneer Motor Bearing Company, 2006
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
OutlineOutlinenn Radial bearingsRadial bearingsnnBore designBore design
nn Thrust bearingsThrust bearingsnn Profile designsProfile designs
nn FluidFluid--film bearing film bearing analysisanalysisnn Reynolds equationReynolds equation
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
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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
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Load Orientations: Load Orientations: radial/thrustradial/thrust
May 2006May 2006
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 22
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
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Radial BearingsRadial Bearings
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Thrust BearingsThrust Bearings
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ElementsElementsnnFunctionFunctionnnPurpose of a fluidPurpose of a fluid--film bearingfilm bearing
nnGeometryGeometrynnKey featuresKey features
nnHydrodynamic theoryHydrodynamic theorynnMaterialsMaterialsnnLiner and supportLiner and support
nnLubricant supplyLubricant supply
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
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SeparationSeparationnnMaintain close clearancesMaintain close clearancesnnMotors / Generators windingsMotors / Generators windingsnnFan seals and bladesFan seals and bladesnnTurbine bladesTurbine blades
May 2006May 2006
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 33
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Hydrodynamic versus HydrostaticHydrodynamic versus Hydrostatic
Ref: Intelligent Mechanics Lab, Ref: Intelligent Mechanics Lab, PukyongPukyong University, websiteUniversity, website
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Sleeve Bearing GeometrySleeve Bearing GeometryRotatingRotatingJournalJournal
HousingHousing
ShellShellBabbittBabbitt
END VIEWEND VIEWCLEARANCECLEARANCEEXAGGERATEDEXAGGERATED
ROTATINGROTATINGJOURNALJOURNAL
SHELLSHELL
BABBITTBABBITT CLEARANCECLEARANCE
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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””..
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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
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 44
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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)
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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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Sleeve Bearing GeometrySleeve Bearing Geometry
ConvergingConvergingFilm w/CCW Film w/CCW rotationrotation
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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.
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Reynolds Equation Reynolds Equation –– 22--D ProfileD Profile
PRESSUREPRESSURE
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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
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 55
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
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Bearing CavitationBearing Cavitation
Axial distributionAxial distribution
Radial Radial distributiondistribution
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 66
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Hydrodynamic DemonstrationHydrodynamic Demonstration
Feel:Feel:
••Reduction in friction Reduction in friction of dry versus of dry versus lubricated.lubricated.
Observe:Observe:
•• Film Film cavitationcavitation
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Bore DesignsBore Designs
Define the Define the bore geometry bore geometry for the desired for the desired operating operating characteristicscharacteristics
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 77
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
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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
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 88
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
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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
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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
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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.
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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
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 99
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
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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).
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
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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
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Tilting Pad BearingsTilting Pad Bearings55--padpad
Load between padLoad between pad
Flooded designFlooded design
Mechanical pivotMechanical pivot
Hydrostatic liftHydrostatic lift
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Tilting Pad BearingsTilting Pad BearingsSegmented filmSegmented film
Concentrated loadConcentrated load
Single point, or lineSingle point, or lineContact supportContact support
May 2006May 2006
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 1010
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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®®
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Pivot TypesPivot Types
LineLine
ContactContact
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Conventional Pivot TypesConventional Pivot Types
CYLINDRICALCYLINDRICAL SPHERICALSPHERICAL BALLBALL--ININ--SOCKETSOCKET
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Quality of Pivot ContactQuality of Pivot Contact
Contact Contact varies with varies with curvature, curvature, load, and load, and temperature.temperature.
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 1111
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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
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Fluid PivotFluid Pivot®®
FlangeFlange--mounted, style JCmounted, style JC
Gear box, style JCGear box, style JC
Pedestal mounted, style JSPedestal mounted, style JS
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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.
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Fluid PivotFluid Pivot®® Exciter AssemblyExciter Assembly
May 2006May 2006
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 1212
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EndEnd
Bearing Bearing Fundamentals IFundamentals I
August 2004August 2004
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 11
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BabbittedBabbitted Bearing OverviewBearing OverviewPart IIPart II
Pioneer Motor Bearing CompanyPioneer Motor Bearing CompanyMay 2006May 2006
VIBRATION INSTITUTE SEMINARVIBRATION INSTITUTE SEMINARCHARLOTTE, NCCHARLOTTE, NC
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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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Oil Distribution GeometryOil Distribution Geometry
OIL INLET OIL INLET HOLEHOLE
Radial grooveRadial groove
Axial grooveAxial grooveBleederBleeder
BleedersBleeders
Spreader
Groove
Spreader
Groove
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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).
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
August 2004August 2004
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 22
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
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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.
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
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Split Slinger RingsSplit Slinger Rings
Trapezoidal Trapezoidal crosscross--sectionsection
August 2004August 2004
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 33
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Slinger Ring ObservationSlinger Ring Observation
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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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
August 2004August 2004
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 44
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
August 2004August 2004
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 55
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Automatic Automatic OilerOiler
Ref: Malinowski, Trico CorporationRef: Malinowski, Trico Corporation
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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””
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Bearing Start/ShutdownBearing Start/Shutdown
Ref. Ref. BasicsBasics, , NoriaNoria, Johnson, , Johnson, 20012001
August 2004August 2004
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 66
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Hydrostatic Lift SystemHydrostatic Lift System
Hydrostatic lift in tilting pad thrust shoes.Hydrostatic lift in tilting pad thrust shoes.
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
August 2004August 2004
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 77
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
=⋅
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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))
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Nominal versus Actual PressureNominal versus Actual Pressure
Actual peak Actual peak pressure will pressure will exceed the nominal exceed the nominal pressure.pressure.
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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
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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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
August 2004August 2004
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 88
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
Minimum Design ClearanceMinimum Design Clearance
Ref. Ref. NealeNeale, , BearingsBearings, , Butterworth Butterworth HeinemanHeineman, , 1998, pg. 39.1998, pg. 39.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
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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
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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.
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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
August 2004August 2004
(c) Pioneer Motor Bearing Company(c) Pioneer Motor Bearing CompanyBearing Bearing FundamentalsFundamentals Sheet Sheet 99
(c) Pioneer Motor Bearing Company, 2006. All rights reserved.
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 Motor Bearing CompanyPioneer Motor Bearing CompanyMay 2006May 2006
PIONEER FLUIDPIONEER FLUID--FILM BEARING WORKSHOPFILM BEARING WORKSHOP
(c) Pioneer Motor Bearing Company, 2006.
OutlineOutlinenn Vibration monitoringVibration monitoringnn Lubricant monitoringLubricant monitoringnn Temperature monitoringTemperature monitoringnn ThermographyThermographynn BalancingBalancing
(c) Pioneer Motor Bearing Company, 2006.
Types of AlarmsTypes of AlarmsnnProtection / AgingProtection / AgingnnStatisticalStatisticalnnGoal basedGoal based
(c) Pioneer Motor Bearing Company, 2006.
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.
(c) Pioneer Motor Bearing Company, 2006.
Machine MonitoringMachine Monitoring
Ref: Mitchell, Ref: Mitchell, MachinerMachiner MonitoringMonitoring
Vibration Vibration monitoring monitoring at or near at or near the the bearingsbearings
(c) Pioneer Motor Bearing Company, 2006.
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
Interface with Predictive Maintenance Programs Sheet 2
(c) Pioneer Motor Bearing Company, 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..
(c) Pioneer Motor Bearing Company, 2006.
Vibration MonitoringVibration Monitoring
NonNon--linear linear vibration vibration responses.responses.
Ref. Ref. EhrichEhrich, , Handbook of Handbook of RotordynamicsRotordynamics, p.4.60, p.4.60..
(c) Pioneer Motor Bearing Company, 2006.
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.
(c) Pioneer Motor Bearing Company, 2006.
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?
(c) Pioneer Motor Bearing Company, 2006.
Flexibility Effect on MonitoringFlexibility Effect on Monitoring
(c) Pioneer Motor Bearing Company, 2006.
Include Casing MeasurementInclude Casing Measurement
May 2006
Interface with Predictive Maintenance Programs Sheet 3
(c) Pioneer Motor Bearing Company, 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
(c) Pioneer Motor Bearing Company, 2006.
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
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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
(c) Pioneer Motor Bearing Company, 2006.
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
(c) Pioneer Motor Bearing Company, 2006.
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
(c) Pioneer Motor Bearing Company, 2006.
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
Interface with Predictive Maintenance Programs Sheet 4
(c) Pioneer Motor Bearing Company, 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.
(c) Pioneer Motor Bearing Company, 2006.
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))
(c) Pioneer Motor Bearing Company, 2006.
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.
(c) Pioneer Motor Bearing Company, 2006.
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)
(c) Pioneer Motor Bearing Company, 2006.
Particle DetectionParticle DetectionnnDetection by many spectroscopic Detection by many spectroscopic
techniquestechniquesnnParticles smaller than 5 micronsParticles smaller than 5 microns
(c) Pioneer Motor Bearing Company, 2006.
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
Interface with Predictive Maintenance Programs Sheet 5
(c) Pioneer Motor Bearing Company, 2006.
Contamination from Oil SystemContamination from Oil System
Ref. Ref. NoriaNoria presentation materialpresentation material
(c) Pioneer Motor Bearing Company, 2006.
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
(c) Pioneer Motor Bearing Company, 2006.
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.
(c) Pioneer Motor Bearing Company, 2006.
Temperature MonitoringTemperature MonitoringnnLimitsLimitsnnJournal bearingsJournal bearingsnnThrust bearingsThrust bearings
(c) Pioneer Motor Bearing Company, 2006.
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
(c) Pioneer Motor Bearing Company, 2006.
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
Interface with Predictive Maintenance Programs Sheet 6
(c) Pioneer Motor Bearing Company, 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.
(c) Pioneer Motor Bearing Company, 2006.
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.
(c) Pioneer Motor Bearing Company, 2006.
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
(c) Pioneer Motor Bearing Company, 2006.
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.
(c) Pioneer Motor Bearing Company, 2006.
Temperature MeasurementTemperature MeasurementOptions for thermocouples Options for thermocouples or RTDor RTD’’s.s.
(c) Pioneer Motor Bearing Company, 2006.
Mounting LocationsMounting Locations
May 2006
Interface with Predictive Maintenance Programs Sheet 7
(c) Pioneer Motor Bearing Company, 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.
(c) Pioneer Motor Bearing Company, 2006.
Thrust Bearing TemperaturesThrust Bearing Temperatures
(c) Pioneer Motor Bearing Company, 2006.
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.
(c) Pioneer Motor Bearing Company, 2006.
Thrust Bearing MeasurementThrust Bearing Measurement
Ref: Mitchell, Ref: Mitchell, MachineryMachinery
*** Standard * Standard monitoring monitoring location for one location for one OEM OEM
(c) Pioneer Motor Bearing Company, 2006.
Mounting LocationsMounting Locations
(c) Pioneer Motor Bearing Company, 2006.
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
Interface with Predictive Maintenance Programs Sheet 8
(c) Pioneer Motor Bearing Company, 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””..
(c) Pioneer Motor Bearing Company, 2006.
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
(c) Pioneer Motor Bearing Company, 2006.
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 …… ??
(c) Pioneer Motor Bearing Company, 2006.
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)
Pioneer Motor Bearing CompanyPioneer Motor Bearing CompanyMay 2006May 2006
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Installation and Handling Sheet 2
Copyright 2006, Pioneer Motor Bearing Company
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).
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
Alignment ConsiderationsAlignment ConsiderationsnnReview historical operational dataReview historical operational datannReview OEM recommendationsReview OEM recommendationsnnMeasure and document as found Measure and document as found
conditionsconditions
Copyright 2006, Pioneer Motor Bearing Company
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
Installation and Handling Sheet 3
Copyright 2006, Pioneer Motor Bearing Company
CatenaryCatenary CurveCurve
= amptampty cosh)(
Applies to Applies to hanging hanging chain, chain, power line, power line, rope, etc.rope, etc.
Copyright 2006, Pioneer Motor Bearing Company
CatenaryCatenary CurveCurveBearing Bearing installation installation seeks to seeks to place all place all bearings on bearings on a caternary a caternary curve.curve.
Copyright 2006, Pioneer Motor Bearing Company
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.
Copyright 2006, Pioneer Motor Bearing Company
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””
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Installation and Handling Sheet 4
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
Bearing AdjustmentBearing Adjustment
Lower Bearing half with adjustment keys centeredLower Bearing half with adjustment keys centered
Copyright 2006, Pioneer Motor Bearing Company
Bearing AdjustmentBearing Adjustment
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
Copyright 2006, Pioneer Motor Bearing Company
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.
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
Misalignment AccommodationMisalignment Accommodation
Blue Check of Turbine Journal BearingBlue Check of Turbine Journal Bearing
August 2004
Installation and Handling Sheet 5
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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.
Copyright 2006, Pioneer Motor Bearing Company
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
Installation and Handling Sheet 6
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
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
Copyright 2006, Pioneer Motor Bearing Company
EndEnd
Installing and Handling Installing and Handling Bearings (partial)Bearings (partial)
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