雨课堂学堂在线学堂云《Electrical Machinery（电机学）（重庆电力高等专科学校）》单元测试考核答案

第1题Inthetwowindingsofthesingle-phasetransformer,thesideoftheoutputelectricenergyiscalled().APrimarywindingBSecondarysidewindingCHigh-voltage

windingDlow-tension

winding第2题WhentheACsupplyvoltageisappliedtotheprimarywindingofthetransformer,ifthesecondarywindingofthetransformerisconnectedwith(),therewillbeelectricenergyoutput.

AExternalcircuitloadBPrimarywindingCHigh-voltage

winding第3题Inanelectricpowersystem,atransformercanconnectdifferent()lines.

ATheresistancelevelBReactancelevelCVoltagegrade第4题Thecurrentofthehighvoltagewindingofthetransformeriscertain()thecurrentofthelowvoltagewinding.

AIsgreaterthanBIsequaltotheCLessthan第5题Inordertotransmittheelectricenergytothedistanceandreducetheelectricenergylossontheline,()ismainlyused.ARaisethevoltagelevelthroughthetransformerBIncreasingthewirecrosssectionreducestheresistanceCImprovethepowerfactortoreducereactivepowerDReducevoltagelevelthroughtransformer第6题Whenthetransformerisinno-loadoperation,iftheotherisunchanged,isreduced,thesub-voltage().AThesameBincreaseCToreduce第7题Theratedcapacity,ratedvoltageandratedcurrentofthehigh-voltagewindingsofthedouble-windingstep-downtransformerarerespectively、、,andthelow-voltagewindingsarerespectively、、,therelationshipbetweenthemis().ABCD第8题Three-phasetransformerratioreferstotheratioof().APrimaryandsecondaryphasepotentialsBPrimaryandsecondarysidelinepotentialsCPrimaryandsecondarysidelinevoltage第1题ThemeaningofapowertransformermodelSFPL-63000/110is().ATheratedvoltageofhighvoltagesideis63000kV,andtheratedvoltageoflowvoltagesideis110kV;BTheratedcapacityofthehighpressuresideis63000kVA,andtheratedcapacityofthelowpressuresideis110kVA;CRatedcapacity63000kVA,highvoltagesideratedvoltage110kV;DTheratedcapacityis63000kVAandtheratedvoltageonthelow-voltagesideis110kV.第2题Thetemperaturereflectedbythetransformerthermometeristransformer().ATheuppertemperatureBThemiddletemperatureCThelowertemperatureDInterturntemperature第3题The+40℃oillevellineofthetransformeroilpillowoillevelmeteristheoilstandardpositionlinemarked().ATransformertemperatureat+40℃;BAmbienttemperatureat+40℃;CWhenthetemperatureoftransformerrisesto+40℃;DTransformertemperatureat+30℃.第4题Theratedvoltageofthesecondarysideofthethree-phasetransformerrefersto()thevoltageofthesecondarysidewhentheratedvoltageisaddedtotheoriginalside.ALinevoltageatnoloadBPhasevoltageatnoloadCLinevoltageatratedload第5题Theoilstoragetankofthetransformerislocatedabovethetransformeroiltankandiscommunicatedwiththeoiltankthrough().ACoolingdeviceBGasrelayCMoistureabsorptiondevice第6题Transformer()withoutload,thevoltageregulationwhentheprimarysideisdisconnectedfromthepowergridiscallednon-excitationvoltageregulation.ASecondarysideBTheprimarysideCHighside第7题Transformerscanbedividedintopowertransformers,instrumenttransformersand()accordingtotheiruses.AGeneraltransformerBBoostertransformerCSpecialtypetransformer第8题Thetransformercoreismadeofsiliconsteelsheetwithgoodmagneticconductivity,whichcanreducethetransformer().AIronlossBCopperlossCMechanicalloss第9题Voltageregulationundersecondarysideloadoftransformeriscalled().AVoltageregulationwithoutexcitationBOn-loadvoltageregulatingCNoloadvoltageregulationTask2.1第1题Thereasonwhytheno-loadcurrentoftheprimarywindingisverysmallwhenthetransformerisinno-loadoperationis().AThenumberofturnsoftheoriginalwindingislarge,andtheresistanceislarge.BLeakagereactanceofprimarywindingisverylarge;CTransformerexcitationimpedanceisveryhigh.第2题Asingle-phasetransformerisinno-loadoperation,andthemainmagneticfluxoftheironcoreiswhenitisconnectedwith220Vsideforatime,andwhenitisconnectedwith110Vsideforasecondtime,then().ABC。第3题Otherconditionsremainunchanged.Ifthenumberofturnsincreasesby10%,andthesizeofandwillbe().AIncreaseto1.1times,unchanged,increasedBIncreasedby1.1times,remainedunchanged,anddecreasedCIncreaseto1.21times,unchanged,increased;DIncreasedby1.21times,remainedunchanged,anddecreased.第4题three-phasetransformer,wiring,itsratiois().A14.43B2C43.3D25第5题Thenumberofturnsontheprimarysideofthetransformerincreasesby5%,andthenumberofturnsonthesecondarysidedecreasesby5%,andtheexcitationreactancewill().AThesameBIncreasedabout10%CReducedabout10%第6题Whena50Hztransformerisconnectedtoa60Hzpowergrid,thesizeoftheexternalvoltageremainsunchanged,andtheexcitationcurrentwillbe().AincreaseBreduceCThesameTask2.2第1题Whenthetransformerisconnectedtotheratedvoltageattheprimarysideandthepureresistiveloadatthesecondaryside,thepowerinputfromtheprimaryside().AContainsonlyactivepower;BContainsonlyinductivereactivepower;CItcontainsbothactivepowerandinductivereactivepower;DItcontainsbothactivepowerandcapacitivereactivepower.第2题Whenthetransformerisloaded,theprimarymagnetomotiveforceis,primaryleakagefluxis,andprimaryleakagereactanceis;

Whenthetransformerisunloaded,theprimarymagnetomotiveforceis,theprimaryleakagefluxis,andtheprimaryleakagereactanceis,andtheirrelationshipis().A;B;C;D。第3题Transformerload()increases,theoreticallyspeaking,itsmainflux().ASlightlyincreased;BSlightlydecreased;CMuchlarger;DIt'salotsmaller.第4题Whenthesecondarycurrentofthetransformerincreases,theprimarycurrent().AReduce;BThesame;CIncreaseaccordingly;DNotnecessarily.第5题Athree-phasepowertransformer,,D,yisconnected,andtheexcitationcurrentisignoredduringload.Whenthelow-voltagesidephasecurrentis808.3a,thephasecurrentofthehigh-voltagesideis().A808.3AB56AC18.67AD32.33A第6题three-phasepowertransformermagneticpotentialbalanceequationis().AThealgebraicsumoftheprimaryandsecondarymagneticpotentialsisequaltothesyntheticmagneticpotentialsBThesumofthetimevectorsoftheprimaryandsecondarymagneticpotentialsisequaltothesyntheticmagneticpotentialsCThearithmeticdifferencebetweentheprimaryandsecondarymagneticpotentialsisequaltothesyntheticmagneticpotentialsTask2.3第1题Thetransformershort-circuitvoltageisrelatedto().ASupplyvoltageBPowerfrequencyCCorematerialDTheloadsize第2题atransformerwithavariableratioofK=10,fromthelow-voltagesideforno-loadtest,theexcitationimpedanceunitvalueofthesecondarysideis16,thentheexcitationimpedanceunitvalueoftheoriginalsideis().A16B1600C0.16第3题asingle-phasetransformerratedvoltageis220/110V,inthehighvoltagesideforshortcircuittest,themeasuredshortcircuitimpedanceunitvalueis0.06,ifinthelowvoltagesideforshortcircuittest,themeasuredshortcircuitimpedanceunitvalueis().A0.06B0.03C0.12D0.24Task2.4第1题Atransformeristhemostefficientat().ABCD第2题Athree-phasepowertransformerisoperatedwithresistiveinductiveload.Underthesameloadcurrent,thehigheris,then().

Abigger,themoreefficient;BBigger,lessefficient;CSmaller,lessefficient;DThesmaller,themoreefficient.第3题Transformerwindingandironcorewillheatinoperation,themainfactorofheatingis()AelectricityBvoltageCIronandcopperlossDinductance第4题Whentheprimarysideofthetransformerisratedvoltage,thesecondarysidevoltage()AMustbetherating;BItvarieswiththeloadcurrentandthepowerfactorCWiththenatureoftheloadchanges;DNolawofchange第5题Theloadofthetransformerisresistiveandinductive,anditsexternalcharacteristiccurveshows().

AAscendingcurveBDescendingcurveCIt'salmostastraightlineDIrregularchange第6题Transformerloadiscapacitive,loadincreases,sidevoltage().

AbeontheriseBinvariantCItcouldgoupordown第7题Transformerprimarywindingplusratedfrequencyratedvoltage,underagivenloadpowerfactor,theratioofthedifferencebetweensecondaryno-loadvoltageand()andsecondaryratedvoltageiscalledtransformervoltagechangerate.

ASecondaryshort-circuitvoltageBSecondaryloadvoltageCPrimaryratedvoltage第8题Theno-loadlossofatransformer=600Wandshort-circuitloss=2100W.Whenthemaximumefficiencyisreached,thetotallossofthetransformeris().

A2700WB4200WC1200WD1500WTask3.1第1题Three-phasetransformerwindingconnectionformisstarconnection(Yconnection),()andzigzagconnection(Zconnection).

ASeriesconnectionBParallelconnectionCTriangularconnection(Dconnection)第2题Single-phasetransformerdeterminationoftheoriginalandvicepolarity,ifthefirstendisthesameend,thereis().

A;B;C。第3题Three-phasetransformerconnectiongroupisY,D5,where"5"represents().

AlaggingBlaggingCleadingDleadingTask3.2第1题Transformerswithdifferentconnectiongroupscannotoperateinparallelbecause().

AVoltagechangerateistoolarge;BTheno-loadcirculationistoolarge;CTheexcitationcurrentatloadistoolarge;DThetransformerratioisdifferentwithdifferentconnectiongroupnumbers.第2题Whenthetwotransformersruninparallel,theloadandshortcircuitimpedance()aredistributed.

AThemagnitudeisinverselyproportionalBThescaleisinverselyproportionalCThescaleisproportionaltothevalue第3题AY/y0-12andaY/y0-8three-phasetransformerwiththesameratio,whetheritcanberuninparallelaftermodification().AcanBcannotCnotalwaysDItcanbeconnectedwithoutchanging第4题Fortwotransformerswiththesameratedcapacity,connectiongroupandchangeratio,iftheunitvalueofshort-circuitimpedanceoftransformerⅰistwicethatoftransformerⅱ,namely,andtheloadof300kVAiscarriedtogetherinparallel,then().A,;B,;C,。第5题Transformeridealparalleloperationconditions,transformerimpedancevoltageallowsthedifferenceof().

A±5%B±10%C±15%第6题Aftertheparalleloperationoftwotransformerswiththesameunitvalueofgroupandimpedancevoltagestandardbutdifferentratio().

ACirculatingcurrentisgeneratedonlyintheprimarywinding;BCirculatingcurrentisgeneratedonlyinthesecondarywindingCCirculatingcurrentisgeneratedinbothprimaryandsecondarywindings第7题Theratio,groupandratedcapacityofthetwotransformersarethesame,buttheirimpedancevoltagenominalidentityisnotequal.If,afterparalleloperation,theiroutputcapacityrelationshipis().

ABCTask4.1第1题Athree-phaseACmotor,thestatorwindingsof2p=4andZ=36aredoublelaminatedwindings,=2and,sothepitchandslotpitchanglesarerespectively().

A6,10°B7,20°C9,30°第2题Thethree-phasewindingsoftheACmotorarearrangedsymmetricallyinspace,andthephasebanddistributionsequenceshouldbe().

AA、B、C、X、Y、ZBA、X、B、Y、C、ZCA、Z、B、X、C、Y第3题Thenumberofparallelbranchesperphaseofintegerslotsingle-layerwindingisa,andthepolarlogarithmisp,andtherelationshipbetweenthemis().

ABC第4题Thedistancebetweenthetwosidesofthemotorwindingiscalled().ApolardistanceBspacingCslotpitchDpitch第5题Three-phaseACmotor,2p=4,usingdoublelayerwinding,eachphasewindinghas()coilgroup.

A2B4C8D12第6题ACthree-phasesymmetricwindingmeansthatthenumberofturnsandconnectionlawofthethree-phasewindingarethesame,but().

ATheaxisofeachphasewindingisstaggeredinspacesuccessively1200:BEachphasewindingaxisisstagger1200electricAngleinspacesuccessiveCEachphasewindingisconnectedtoathree-phasesymmetricalcurrentDEachphasewindingisconnectedtothethree-phaseACcurrent.Task4.2第1题Afterthestatorwindingofthree-phaseasynchronousmotoradoptsdistributedshortdistance,thefundamentalwavecomponentofinducedELECTROmotiveforceisreduced,butthemainadvantagesare().AImprovedEMFwaveformBCanincreaseaharmonicemfCCanincreasethemotorspeedDCanimprovethemagneticforcewaveform第2题Thenumberofstatorslotsofathree-phaseACmotoris36,thepolarlogarithmis3,andthephasedifferenceofthefundamentalEMFoftheconductorinthetwoadjacentslotsofthedouble-layershort-distancedistributedwindingis().ABCD第3题Iftheinducedelectromotiveforceofanintegraldistancecoilis10V,afterchangingittoashort-distancecoilandsettingitsshort-distancecoefficientas0.96,itsinducedelectromotiveforcebecomes().ALessthan10VBIsequalto10VCGreaterthan10VIsequalto9.6VDIsequalto9.6V第4题Thereasonthattheinducedelectromotiveforceofthedistributedwindingissmallerthanthatoftheconcentratedwindingis().AThepositiondifferenceofeachcoilinspacecausesthemaximuminducedelectromotiveforceofeachcoiltoappearatdifferenttimes;BTheinducedelectromotiveforceofeachcoildistributedhastimephasedifference,anditscompositevalueisphasorand;CThephasorsumoftheinducedelectromotiveforceofthedistributedcoilsislessthanthealgebraicsumoftheinducedemfoftheconcentratedcoils;DAlloftheabove.Task4.3第1题Ifthethree-phasesymmetriccurrentof,,andisenteredintothethree-phasesymmetricwinding,theamplitudeofthethree-phasefundamentalwaveresultantmagnetomotiveforceislocatedat()whenThethree-phasesymmetricwindingis.AU-phasewindingaxisBV-phasewindingaxisCW-phasewindingaxisDAlocationawayfromtheaxisofthethree-phasewinding第2题TheamplitudeofthefundamentalwavepulsatingmagnetomotiveforcegeneratedbytheV-phaseACwindingisalwaysat().Aontheaxisofu-phasewindingBontheaxisofv-phasewindingCWphasewindingaxisDUncertainty第3题Assumingthattheamplitudeofthesingle-phasepulsatingmagnetomotiveforcedecomposedintotworotatingmagnetomotiveforcesisf,theamplitudeofthethree-phasesyntheticmagnetomotiveforceis()A2/3FBFC3/2FD3F第4题Ifthethree-phasesymmetricalwindingisconnectedwiththethree-phasethree-phasecurrentiA=Im,iB=Im,iC=Im,whenwt=210°,theamplitudeofthethree-phasefundamentalwaveresultantmagnetomotiveforceislocatedat().AA-phasewindingaxisBB-phasewindingaxisCC-phasewindingaxisDApositionoutsidetheaxisofthethree-phasewinding第5题Themagneticforcegeneratedbyacsingle-phasewindingisafunctionofbothtimeandspace,whichrefersto().AThecurrentisAfunctionoftimeandthemagnetomotiveforceisAfunctionofspace;BThemagnetomotiveforceisafunctionoftimeandthecurrentisafunctionofspace;CThemagneticforceisdistributedcosineinspaceandrotateswithtime;DTheamplitudeofthemagnetomotiveforceispulsatingwithtime,andthemagnetomotiveforceisdistributedcosineinspace.第6题ThesyntheticfundamentalmagnetomotiveforcegeneratedbytheACthree-phasewindingisafunctionofbothtimeandspace,whichrefersto().AThecurrentisAfunctionoftimeandtheMAGNETOmotiveforceisAfunctionofspace;BThemagnetomotiveforceisafunctionoftimeandthecurrentisafunctionofspace;CThemagneticforceisdistributedcosineinspaceandrotateswithtime;DTheamplitudeofthemagnetomotiveforceispulsatingwithtime,andthemagnetomotiveforceisdistributedcosineinspace.第7题Thepropertiesofsyntheticfundamentalmagnetomotiveforceproducedbythree-phaseACwindingare()AThemagnetomotiveforceisasinewavealongthecircumferenceoftheairgap.BTheamplitudeofthemagnetomotiveforcesinewaveisconstant;CThemagnetomotiveforcesinewaverotatesatasynchronousspeedDAlloftheabove.Task5.1第1题Thegeneratorgenerateselectromotiveforcethroughrotation.Itisadevicethatcancontinuouslyprovidecurrent,soitiscalled().AThepowersupplyBElectromotiveforceCVoltagesourceDVoltage第2题Thesynchronousspeedofthegeneratorandthemagneticpolelogarithmofthegeneratorare().ADirectproportionalityBInverseproportionalrelationCOutofproportionDThesame第3题TheEMFfrequencyofasynchronousgeneratoris50Hz,thespeedis600r/min,anditspolarlogarithmis().A2B5C10D20第4题Thegeneratingcapacityofthegeneratorismeasuredinkwh,whichistheunitnameof().AElectricpowerBvoltageCpotentialDelectricityTask5.2第1题单选题Thetemperaturemeasuringcomponentsofgeneratorstatorcoilareusuallyburiedin()AUpperbarnotchBBetweenlowerbarandironcoreCBetweenupperandlowerbarsDLowerwirebarnotch第2题Thethree-phasestatorwindingsofthegeneratoraregenerallystarconnection,whichismainlytoeliminate().AAccidentallyharmonicBThreetimesharmonicCFivetimestheharmonicDHigherharmonic第3题Ratedpowerofsynchronousgeneratorrefersto().AMechanicalpowerinputtotherotatingshaftBThemechanicalpoweroutputontherotatingshaftCTheelectricalpowerinputtothearmatureportDTheelectricalpoweroutputfromthearmatureportTask6.1第1题ThemeaningofapowertransformermodelSFPL-63000/110is().ATheratedvoltageofhighvoltagesideis63000kV,andtheratedvoltageoflowvoltagesideis110kV;BTheratedcapacityofthehighpressuresideis63000kVA,andtheratedcapacityofthelowpressuresideis110kVA;CRatedcapacity63000kVA,highvoltagesideratedvoltage110kV;DTheratedcapacityis63000kVAandtheratedvoltageonthelow-voltagesideis110kV.第2题Whenthegeneratorisinoperation,whenthestatormagneticfieldandtherotormagneticfieldrotateinthesamedirectionandwiththesame(),itiscalledsynchronization.AspeedBfrequencyCamplitudeDValidvalues第3题Synchronousgeneratorwiththree-phasesymmetricloadstableoperation,rotorexcitationwinding().AInductivelowfrequencyelectromotiveforceBInductionfundamentalemfCInductiondirectcurrentelectromotiveforceDNon-inductiveemf第4题Whensynchronousgeneratorloadisrunning,when,thespaceAnglebetweenandis().ABCD第5题Therearethree-phasewindingswithamutualdifferenceof120°inthegeneratorstator.Whenthesymmetricalthree-phaseACcurrentflows,a()willbegeneratedinthestator.AConstantmagneticfieldBPulsedmagneticfieldCArotatingmagneticfieldDPerpetualmagneticfield第6题Synchronousgeneratorstatorrotatingmagneticfieldhasthecharacteristicsof().AThenumberofmagneticpolesandthespeedoftherotorarethesame,butthesteeringisdifferent;BThenumberofmagneticpolesandsteeringisthesameasthatoftherotor,butthespeedisdifferent;CIthasthesamespeedandsteeringastherotor,andthesamemagneticpolelogarithms.Task6.2第1题Whenthegeneratorisrunningwithpureresistanceload,thephasedifferencebetweenvoltageandcurrentisequalto().A180°B90°C0°D5°第2题Whenthegeneratorisrunningwithload,thereisonlyenergy()betweenthegeneratorandtheload.AConsumptionprocessBExchangeprocessCConsumptionprocessandexchangeprocessDNotnecessarily第3题Duringsymmetricalloadoperation,theimpedanceofsalientpolesynchronousgeneratorisintheorderof().ABCD第4题Therelationshipbetweenleakageresistance,armaturereactionreactanceandsynchronousreactanceofsynchronousgenerators().A>>B>>C>>D>>第5题Correspondingtotheexcitationreactanceoftheasynchronousmotor,thereis().ALeakagereactorBArmaturereactionreactorCSynchronousreactanceDThereisnocorrespondingreactancetoit.第6题Synchronousreactancerepresentsthethree-phasesymmetricalandstableoperationofsynchronousmotor().AAcomprehensiveparameterofthemagneticfieldofarmaturereactionBAcomprehensiveparameterofairgapsynthesismagneticfieldCAcomprehensiveparameterofarmaturereactionmagneticfieldandarmatureleakagemagneticfieldDAcomprehensiveparameterofexcitationfieldandexcitationleakagefield.第7题Athree-phasesynchronousgeneratorrunsstablyunderasymmetricalload()Atthistime,thearmaturereactionpropertyis().AStraight-axismagneticarmaturereflection;BTherearebothstraight-axisdemagneticarmaturereactionandcross-axisarmaturereaction;CTherearebothstraight-axismagneticarmaturereactionsandcross-axisarmaturereactions;DTherearebothstraight-axisarmaturereactions(demagnetization,magnetism-assistant)andcross-axisarmaturereactions.第8题Whenthesynchronousgeneratorisrunninginasteadystate,iftheloadisinductive,thenatureofitsarmaturereactionis().ACross-axisarmaturereactionBStraight-axisdemagnetizationarmaturereactionCStraightaxisdemagnetizationandintersectionalarmaturereactionDStraightaxismagnetizationreactswithcross-axisarmatureTask6.3第1题Thereasonwhythestableshort-circuitcurrentofthesynchronousgeneratorisnotverylarge().ALargeleakageimpedanceBShort-circuitcurrentproducesstrongdemagnetization;CThearmaturereactionproducesmagnetizationDThesynchronousreactanceisrelativelylarge.第2题Whenmeasuringtheshort-circuitcharacteristicsofsynchronousgenerators,ifthespeeddecreasesby,themeasuredshort-circuitcharacteristics().ABeunchangedBIncreaseby0.8timesCReduceby0.8times.Task7.1第1题Whenthesynchronousgeneratorisconnectedinquasisynchronousparallelwiththepowergrid,allotherconditionsaremetexceptthatthegeneratorvoltageisonlylessthan5%ofthepowergridvoltage.Atthistime,ifthegeneratorisclosedinparallel,thegeneratorwill()

AGeneratehugecurrent,sothatthegeneratorcannotbeparalleledBGenerateasmallcurrent,whichisinductivecurrentCGenerateasmallcurrent,whichisacapacitivecurrentDGenerateasmallcurrent,whichisanactivecurrent第2题Intheprocessofgeneratorparalleling,whenthephaseofgeneratorvoltageandsystemvoltageisinconsistent,impulsecurrentwillbegenerated.Themaximumvalueofimpulsecurrentoccurswhenthedifferencebetweenthetwovoltagesis().A0°B90°C180°D100°第3题Whenthesynchronousgeneratorisconnectedinparallelwiththepowergrid,someconditionsmustbemet,butthefirstconditionthatmustbeabsolutelymetis()

AEqualvoltageBSamephasesequenceCSamefrequencyDSamephase第4题Ifthesynchronousgeneratorisconnectedtothepowergridaccordingtotheidealquasisynchronousmethodwithoutanyadjustment,theoutputpowerofthesynchronousgeneratortothepowergridis()

AP>0,Q>0BP>0,Q<0CP<0,Q>0DP=0;Q=0Task7.2第1题Thereactancethatmainlyaffectsthemaximumelectromagnetictorqueofsynchronousgeneratoris()

AThestatorleakagereactanceBSynchronousreactanceCReactanceofarmaturereaction第2题Forasalientpolesynchronousgeneratoroperatinginparallelwithinfinitepowergrid,iftheexcitationislost,themaximumelectromagneticpowerofthemotorappearsatthepowerangleof()ABCD第3题Afterthecurrentflowsthroughthegeneratorwinding,itwillgeneratelossandheatintheconductorofthewinding.Thislossiscalled().AironlossBcopperlossCeddy-currentlossDOtherlossTask7.3第1题Ino