ch06

Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-0PowerPointSlidestoaccompanyElectricMachineryFourthEditionStephenJ.ChapmanChapter6DCMachineryFundamentalsCopyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-1Schematicrepresentationsofadcmachine.Figure7.1Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-2Rectifiedcoilvoltagesandresultantvoltagebetweenbrushesinadcmachine.Figure7.2Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-3Typicalformofmagnetizationcurvesofadcmachine.Figure7.3Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-4Field-circuitconnectionsofdcmachines:(a)separateexcitation,(b)series,(c)shunt,(d)compound.Figure7.4Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-5Volt-amperecharacteristicsofdcgenerators.Figure7.5Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-6Speed-torquecharacteristicsofdcmotors.Figure7.6Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-7Dcmachinearmaturewindingwithcommutatorandbrushes.(a),(b)Currentdirectionsfortwopositionsofthearmature.Figure7.7Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-8Waveformofcurrentinanarmaturecoilwithlinearcommutation.Figure7.8Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-9Armature-mmfandflux-densitydistributionwithbrushesonneutralandonlythearmatureexcited.Figure7.9Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-10Fluxwithonlythearmatureexcitedandbrushesonneutral.Figure7.10Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-11Armature,main-field,andresultantflux-densitydistributionswithbrushesonneutral.Figure7.11Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-12Motororgeneratorconnectiondiagramwithcurrentdirections.Figure7.12Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-13Short-shuntcompound-generatorconnections.Figure7.13Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-14Magnetizationcurvesfora250-V1200-r/mindcmachine.Alsoshownarefield-resistancelinesforthediscussionofself-excitationinSection7.6.1.Figure7.14Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-15Equivalentcircuitforanalysisofvoltagebuildupinaself-exciteddcgenerator.Figure7.15Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-16Crosssectionofatypicalpermanent-magnetmotor.Arrowsindicatethedirectionofmagnetizationinthepermanentmagnets.Figure7.17Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-17(a)DimensiondefinitionsforthemotorofFig.7.17.(b)approximatemagneticequivalentcircuit.Figure7.18Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-18Equivalentcircuitofapermanent-magnetdcmotor.Figure7.20Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-19Sectionofdcmachineshowingcompensatingwinding.Figure7.22Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-20Schematicconnectiondiagramofadcmachine.Figure7.24Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-21Series-connecteduniversalmachine.Figure7.25Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-22Typicaltorque-speedcharacteristicsofaseriesuniversalmotor.Figure7.26Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-231200r/minmagnetizationcurveforthedcgeneratorofProblem7.4.Figure7.27Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-24Seriescranemotor(Problem7.22):(a)hoistingconnectionand(b)loweringconnection.Figure7.28Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-25ArmatureWindings-TermsandDefinitions•polepitch=distancebetweencentersoftwoadjacentpoles=180oed•coilpitch=distancebetweentwosidesofacoil•full-pitch:coilpitch=polepitch•short-pitch:coilpitchpolepitch(mainlyinac-machines)•electricaldegreesθed•mechanicaldegreesθmd•pnumberofpolesCopyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-26Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-27pZy21FirstPitchSecondPitch2yKyCommutatorPitchLapWindingArmatureWindings-Copyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-28•onecoilbetweentwoadjacentcommutatorbars•1/pofthetotalcoilsareconnectedinseriesCopyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.7-29•suitableforhigh-currentlowvoltagenumberofparallelpaths=numberofpoles=numberofbrushespa22paCopyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionord