Current Signature Analysis for Condition Monitoring of Cage Induction Motors - Industrial Application and Case Histories

426 Pages·2017·21.95 MB·English

by  Culbert, Ian, Thomson, William T

CURRENT SIGNATURE
ANALYSIS FOR CONDITION
MONITORING OF CAGE
INDUCTION MOTORS
IEEEPress
445HoesLane
Piscataway,NJ08854
IEEEPressEditorialBoard
TariqSamad,EditorinChief
GeorgeW.Arnold XiaoouLi RayPerez
GiancarloFortino VladimirLumelsky LindaShafer
DmitryGoldgof Pui-InMak ZidongWang
EkramHossain JeffreyNanzer MengChuZhou
CURRENT SIGNATURE
ANALYSIS FOR CONDITION
MONITORING OF CAGE
INDUCTION MOTORS
Industrial Application and
Case Histories
WILLIAM T. THOMSON
IAN CULBERT
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ISBN:978-1-119-02959-5
PrintedintheUnitedStatesofAmerica
10 9 8 7 6 5 4 3 2 1
CONTENTS
ABOUTTHEAUTHORS xiii
OBITUARYTOIANCULBERT xv
ACKNOWLEDGMENTS xvii
FOREWORD xix
PREFACE xxiii
NOMENCLATURE xxvii
ACRONYMSANDABBREVIATIONS xxxiii
RELEVANTUNITSOFEQUIVALENCEUSEFULFORTHISBOOK xxxv
CHAPTER1 MOTORCURRENTSIGNATUREANALYSISFORINDUCTION
MOTORS 1
1.0 Introduction 1
1.1 HistoricalDevelopmentofMCSAandGoalsofThisBook 4
1.2 BasicTheoryofOperationofthe3-PhaseInductionMotor 6
1.2.1 KeyEquationsforMCSABasedonOperationofa3-PhaseInduction
Motor 13
1.2.2 InterpretationofMotorNameplateandApplicationofBasicEquations 15
1.3 StartingandRun-UpCharacteristicsofSCIMs 20
1.3.1 CalculationofRun-UpTimeofSCIMDrivingaMechanicalLoad 24
1.4 IllustrationsofConstructionofaLargeHVSCIM 29
1.5 Questions 33
References 34
CHAPTER2 DESIGN,CONSTRUCTION,ANDMANUFACTUREOFSQUIRREL
CAGEROTORS 39
2.0 Introduction 39
2.1 AluminumandCopperDie-CastWindings 40
2.2 FabricatedSquirrelCageWindings 43
2.2.1 RotorBarDesign,Shape,andInstallation 43
2.2.2 DesignandConstructionofShortCircuitingEndRings,BartoEnd
RingJoints,andEndRingRetainingRings(ERRs) 48
2.3 DesignandManufacturingFeaturesofSquirrelCageRotorWindingsto
MinimizeFailures 52
2.4 Questions 53
References 54
v
vi CONTENTS
CHAPTER3 CAUSESOFBREAKSINSQUIRRELCAGEWINDINGSDURING
DIRECT-ON-LINESTARTSANDSTEADY-STATEOPERATION 55
3.0 Introduction 55
3.1 MechanicalStressesandConsequentialForcesonRotorBarsandEndRings 56
3.2 ThermalStressesintheRotorBarsandEndRings 57
3.3 BrokenBarsandEndRingsDuetoCombinedMechanicalandThermal
StressesWhenStartingHighInertiaLoads 59
3.4 RotorBarStressesResultingfromaLooseSlotFit 60
3.5 StrengthsandWeaknessesofCertainBarandEndRingShapesandTypes
ofJoints 62
3.6 PulsatingLoadsDuetoCrushersandCompressors 62
3.7 Direct-On-LineStartingofLargeInductionMotorsDrivingHighInertiaFans 63
3.8 Direct-On-LineStartingofLargeInductionMotorsDriving
CentrifugalPumps 66
3.9 LimitationsonRepetitiveMotorStarts 68
3.9.1 StartingCapability 68
3.9.2 AdditionalStarts 69
3.9.3 AdditionalNamePlateData 69
3.10 CriteriaforDesignofSquirrelCageRotorWindings 69
3.10.1 TotalMotorandDrivenEquipmentInertia 69
3.10.2 DrivenEquipmentTorque–SpeedCurveDuringStarting 70
3.10.3 MotorTorque–SpeedatMinimumSupplyVoltageDuringStarting 70
3.10.4 MotorConsecutiveStartingRequirements 71
3.10.5 SquirrelCageRotorMechanicalConfiguration 71
3.10.6 RotorBarMaterialandShape 72
3.11 SamplesofBreaksinSquirrelCageRotorWindings 72
3.12 Questions 77
References 77
FurtherReading 78
CHAPTER4 MOTORCURRENTSIGNATUREANALYSIS(MCSA)TODETECT
CAGEWINDINGDEFECTS 79
4.0 Summary 79
4.1 Introduction 79
4.2 DerivationofCurrentComponentatf(1−2s) 82
4.3 ReasonsforCurrentComponentatf(1+2s) 83
4.4 SpectrumAnalysisofCurrent 85
4.4.1 MeasurementofCurrentandMCSAinIndustry 87
4.4.2 IntroductorySampleofCurrentSpectrafromIndustrialSCIMs 89
4.4.3 ThedBScaleforMCSAandSpecificationforSpectrumAnalysisof
Current 91
4.5 SeverityIndicatorsforAssessingConditionofCageWindingsatFull-Load 93
4.5.1 SeverityIndicatorforAssessingConditionofCageWindingson
ReducedLoad 96
4.5.2 ExperimentalTestsattheRobertGordonUniversity,Scotland 96
4.5.3 MCSATestsatFull-Load—NormalCageWinding,1,2,and10
BrokenBars 99
CONTENTS vii
4.5.4 CorrectionFactortoEstimateCageWindingConditionDuring
ReducedLoad 106
4.5.5 ApplicationofaBrokenBarCorrectionFactorinIndustry 109
4.6 ThedBBrokenBarSeverityChart 110
4.7 InfluenceofNumberofRotorBarsandPoleNumberontheEquivalentBroken
BarFactorwithMeasureddBDifferenceValues 111
4.8 Questions 116
References 118
CHAPTER5 MCSAINDUSTRIALCASEHISTORIES—DIAGNOSISOFCAGE
WINDINGDEFECTSINSCIMsDRIVINGSTEADYLOADS 119
5.0 IntroductionandSummaryofCaseHistories 119
5.1 CaseHistory(2000–2014)—SummaryandKeyFeatures 120
5.1.1 MCSADiagnosis 120
5.2 CaseHistory(1983)—SummaryandKeyFeatures 122
5.2.1 MCSADiagnosisandInspection 123
5.3 CaseHistory(1982)—SummaryandKeyFeatures 125
5.3.1 MCSADiagnosisandInspection 125
5.4 CaseHistory(2002)—SummaryandKeyFeatures 128
5.4.1 MCSADiagnosisandInspection 129
5.5 CaseHistory(1985–1987)—SummaryandKeyFeatures 133
5.5.1 MCSADiagnosisandInspection 133
5.6 CaseHistory(2006)—SummaryandKeyFeatures 136
5.6.1 MCSADiagnosisandInspection 136
5.7 MCSACaseHistory(2004)—SummaryandKeyFeatures 139
5.7.1 MCSADiagnosisandInspection 140
5.8 MCSACaseHistory(2004)—SummaryandKeyFeatures 141
5.8.1 MCSADiagnosisandInspection 142
5.9 Questions 143
References 144
CHAPTER6 MCSACASEHISTORIES—DIAGNOSISOFCAGEWINDING
DEFECTSINSCIMsFITTEDWITHENDRINGRETAININGRINGS 147
6.0 IntroductionandSummaryofCaseHistories 147
6.1 CaseHistory(2006)—Summary 148
6.1.1 MCSADiagnosis 149
6.1.2 Inspection 154
6.1.3 RCFAofBrokenRotorBarsandSolution 155
6.2 ConcludingRemarksonthisChallengingCaseHistory 160
6.3 CaseHistory(1990)—SummaryandKeyFeatures 161
6.3.1 MCSADiagnosis 162
6.3.2 Inspection 164
6.4 SummaryandLessonsLearnedfromIndustrialCaseHistoriesinChapters5
and6 166
6.4.1 Conclusions 168
6.5 Questions 170
References 172
viii CONTENTS
CHAPTER7 MCSACASEHISTORIES—CYCLICLOADSCANCAUSEFALSE
POSITIVESOFCAGEWINDINGBREAKS 173
7.1 IntroductionandSummaryofCaseHistories 173
7.1.1 EffectonCurrentSpectraduetoOscillationsfromMechanicalLoads 174
7.1.2 MCSALaboratoryExperimentswithaCyclicLoadandaBroken
RotorBar 176
7.2 CaseHistory(2006)—EffectofGasRecyclinginaCentrifugalGas
CompressorandtheDetectionofBrokenRotorBars 179
7.2.1 MCSADiagnosis 179
7.3 CaseHistory:FalsePositiveofBrokenRotorBarsDuetoRecyclingofGasin
aCentrifugalCompressor 180
7.3.1 SummaryandKeyFeatures 180
7.3.2 MCSADiagnosis 181
7.4 TwoCaseHistories(2002and2013)—BrokenRotorBarsintheSameSCIM
withoutandwithGasRecyclinginaGasCompressor 185
7.4.1 CaseOne2002:SummaryandKeyFeatures 185
7.4.2 CaseTwo2012–2013:SummaryandKeyFeatures 185
7.4.3 CaseOne2002:MCSADiagnosisandInspection 186
7.4.4 CaseTwo:MCSADiagnosisandInspection,2012–2013 188
7.5 CaseHistory1986–FluidCouplingDynamicsCausedaFalsePositiveofa
CageWindingBreak 193
7.5.1 SummaryandKeyFeatures 193
7.5.2 MCSADiagnosisandInspection 194
Appendix7.A.1 DerivationofSidebandsduetoLowFrequencyOscillation
fromtheMechanicalLoad 197
7.6 Questions 198
References 200
CHAPTER8 MCSACASEHISTORIES—SCIMDRIVESWITHSLOWSPEED
GEARBOXESANDFLUCTUATINGLOADSCANGIVEFALSE
POSITIVESOFBROKENROTORBARS 201
8.1 IntroductionandSummaryofCaseHistories 201
8.1.1 InfluenceofMechanicalMisalignmentontheCurrentSpectrum 202
8.1.2 MCSAExperimentalResultsasaFunctionofMisalignment 206
8.1.3 InterpretationofCurrentSpectrumasaFunctionofMisalignment 207
8.1.4 MCSAExperimentalResultswithaSpeedReductionGearboxinthe
SCIMTrain 210
8.2 CaseHistory(1989)—SlowSpeedCoalConveyor,LoadFluctuations,and
GearboxintheDriveTrain 213
8.2.1 SummaryandKeyFeatures 213
8.2.2 MCSADiagnosis 214
8.3 MCSACaseHistory(1990)—PossibleFalsePositiveofBrokenRotorBarsin
aSCIMDrivingaCoalConveyorViaaSlowSpeedGearbox 216
8.3.1 SummaryandKeyFeatures 216
8.3.2 MCSADiagnosis 216
8.4 CaseHistory(1992)—ImpossibletoAnalyzeMCSADataDuetoSevere
RandomCurrentFluctuationsfromTheMechanicalLoadDynamicsfromthe
CoalCrusher 217
8.4.1 SummaryandKeyFeatures 217
8.4.2 MCSADiagnosis 218
CONTENTS ix
8.5 CaseHistory(1995)—SuccessfulAssessmentofCageWindingsWhenthe
LoadCurrentFluctuationsareNormalfromaSCIMDrivingCoalCrusher 221
8.5.1 SummaryandKeyFeatures 221
8.5.2 MCSADiagnosis 222
8.6 TwoCaseHistories(2015)—FalsePositiveofBrokenBarsinOneofthe
SCIMsDrivingThrustersonanFPSOIfInfluenceofDriveDynamicsis
Discounted 227
8.6.1 SummaryandKeyFeatures 227
8.6.2 MCSADiagnosis(2013–2015) 229
8.6.3 Conclusions 233
8.7 Questions 237
References 238
CHAPTER9 MISCELLANEOUSMCSACASEHISTORIES 241
9.0 IntroductionandSummaryofCaseHistories 241
9.1 PossibleFalsePositivesofCageWindingBreaksinTwo1850kWSCIMs,
DuetoNumberofPoles(2p)EqualtoNumberofSpiderSupportArms(S )on
p
Shaft(1991) 242
9.1.1 ModulationofMagnetizingCurrentatTwiceSlipFrequency 242
9.1.2 ApplicationofMCSAtoSCIMswith2p=Sp 245
9.1.3 SummaryandKeyFeaturesinCaseHistory9.1(In1991) 247
9.1.4 MCSADiagnosisandInspection(1991) 248
9.1.5 Conclusions 250
9.2 CaseHistory(2007)—SCIMwithNumberofPolesEqualtoNumberof
KidneyShapedAxialDuctsintheRotor—FalsePositiveofBrokenBars
PreventedbyLoadChanges 251
9.2.1 SummaryandKeyFeatures 251
9.2.2 MCSAMeasurementsandAnalysis(2007) 251
9.3 TwoCaseHistories(2005–2008)—NormalandAbnormalPumpingDynamics
inTwoSCIMSeawaterLiftPumpDriveTrains 253
9.3.1 SummaryandKeyFeatures 253
9.3.2 DescriptionofaSeawaterLiftPump(SWLP)DriveTrain 253
9.3.3 MCSAMeasurementsandAnalysis(2005) 254
9.3.4 MCSAMeasurementsandAnalysis(2008) 257
9.4 MCSACaseHistory(2006–2007)—SlackandWornBeltDrivesinTwoSCIM
CoolingFanDrivesinaCementFactory 259
9.4.1 SummaryandKeyFeatures 259
9.4.2 MCSAMeasurementsandAnalysis 259
9.5 ApplicationofMCSAtoInverter-FEDLVandHVSCIMs 263
9.5.1 SummaryandKeyFeatures 263
9.5.2 MCSAResultsfromLaboratory-BasedPWMInverter-Fed
SCIM(1987) 263
9.5.3 CaseHistory(2005)—MeasurementsandAnalysisfromanLV
Inverter-FedSCIMWithNoCageWindingBreaks 265
9.5.4 CaseHistory(2008)—MeasurementsandAnalysisfromaLarge,
6300kW/8445HPInverter-FedSCIMWithNoCageWindingBreaks 266
9.6 CaseHistory(1990)—AssessmentoftheMechanicalOperationalConditionof
anElectricalSubmersiblePump(ESP)DrivenbyaSCIMUsedinArtificial
OilLift 267
9.6.1 MCSAResult 268
x CONTENTS
9.7 Questions 270
References 271
CHAPTER10 MCSATOESTIMATETHEOPERATIONALAIRGAP
ECCENTRICITYINSQUIRRELCAGEINDUCTIONMOTORS 273
10.0 SummaryandIntroduction 273
10.1 DefinitionofAirgapEccentricity 274
10.2 CausesandAssociatedTypesofAirgapEccentricity 276
10.3 UnbalancedMagneticPull(UMP)andRotorPull-Over 281
10.4 CurrentSignaturePatternduetoAirgapEccentricity 284
10.4.1 PredictorEquations 284
10.4.2 ExampleofSignalProcessingStrategy 287
10.4.3 TwoCaseHistories(1985)—AssessmentofOperationalAirgap
EccentricityinHVSCIMsDrivingLargeFDFans 291
10.5 Questions 294
References 295
CHAPTER11 CASEHISTORIES—SUCCESSFULANDUNSUCCESSFUL
APPLICATIONOFMCSATOESTIMATEOPERATIONALAIRGAP
ECCENTRICITYINSCIMS 299
11.0 SummaryandListofCaseHistories 299
11.1 FlowChartofMCSAProceduretoEstimateOperationalAirgapEccentricity 300
11.2 CaseHistory(1989)—LowLevelofAirgapEccentricityinaSCIMDrivinga
CentrifugalAirCompressor 302
11.2.1 Summary 302
11.2.2 MCSADiagnosis 302
11.2.3 IllustrationofAirgapEccentricityAnalysisDuringaLightlyLoaded
RunandaNo-LoadUncoupledRun 306
11.3 TwoCaseHistories(2004)—OperationalAirgapEccentricityinNominally
IdenticalSCIMsDrivingPumpsinaCCGTPowerStation 307
11.3.1 MCSAMeasurementsandDiagnosis 307
11.4 FourCaseHistories(2005)—AbnormalLevelofAirgapEccentricityina
Large,LowSpeed,HVMotorDrivingaCoolingWaterPumpinaPower
Station 310
11.4.1 Summary 310
11.4.2 MCSAMeasurementsandAnalysis 312
11.4.3 AirgapMeasurementsBeforeandAfterModificationsandFinal
MCSATest 315
11.5 CaseHistory(1988)—HighLevelofAirgapEccentricityinanHVSCIM
DrivingaPumpinaLargeOilStorageTankFacility 318
11.5.1 Summary 318
11.5.2 MCSAMeasurementsandAnalysis 319
11.5.2.1 MotorA:BrokenRotorBarAnalysis 319
11.5.2.2 MotorA:AirgapEccentricityAnalysis 320
11.5.2.3 MotorB:AirgapEccentricityAnalysis 321
11.5.2.4 MotorA:MeasurementofAirgaps 322
11.6 CaseHistory(2001)—HighAirgapEccentricityinaCoolingWaterPump
MotorthatCausedSevereMechanicalDamagetoHVStatorCoils 324