雨课堂学堂在线学堂云《Motor and Electrical Control Technology（四川工程职业技术）》单元测试考核答案

第1题Voltagetransformerisinuse,notallowed.()AprimarysideopencircuitBsecondarysideshortcircuitCtertiarysideopencircuitDopencircuitfourside第2题Currenttransformerisinuse,notallowed.()AopencircuitBopencircuitsecondarysideCshortcircuitDopencircuitfourside第3题Short-circuitimpedanceofelectricweldingtransformer()AissmallBislargeCisconstantDandcannotbedetermined第4题Thethree-itemmagneticcircuitbetweenthethree-itemcoretransformeris().AiscorrelatedtoeachotherBisindependentofeachotherCisindependentandiscorrelatedDwhereonlytwophasesarecorrelated第5题Theefficiencyofthetransformerdependsonthesizeof()AironlossandcopperlossandloadBironlossandcopperlossCloadDcopperloss第6题Mainfactorsaffectingtheexternalcharacteristicsofthetransformer(

)Aironloss,copperloss,andloadBironlossandcopperlossCloadDcopperlossandload第7题Whenthetransformerisrunninginno-load,thepowerfactorisgenerallyin()A0.8~1.0B0.1~0.2C0.3~0.6D0.7~0.8第8题Theloadcoefficientofthetransformerrefersto(

)AI2/I2NBI1/I2CI2/I1DI1N/I2N第9题Thecrosssectionoftheironyokeisprovidedwith().ApentagonBouterTCinnerTDrectangle正确答案：BCD第10题Transformerisdividedinto()accordingtothenumberofwindings.Asingle-winding(self-coupling)transformerBdouble-windingtransformerCsix-windingtransformerDmulti-windingtransformer正确答案：ABD第11题Commonfaultsofsmalltransformersare().AcoilleakageBcoilshortcircuittocoreCleadlineendbreakDcoilexplosion正确答案：ABC第12题Technicalparametersofthetransformerare().AratedcapacityBratedvoltageCratedcurrentDshort-circuitcurrent正确答案：ABC第13题Experimentalmethodforthedeterminationofisopolarityis(

).AcontrolvariablemethodBDCmethodCACmethodDtablecheckingmethod正确答案：CB第14题Toensurethequalityofelectricweldingandthestabilityofelectricarccombustion,theelectricweldingtransformershouldmeetthefollowingrequirements().AThereshouldbesufficientarcinductionvoltage(60~75V)Bwhenon-load(i.e.welding),theelectricweldingtransformershallhavetheexternalcharacteristicsofrapidpressurereduction,andtheoutputvoltagewithratedload(arcbetweenweldingclampandworkpiece,andstablecombustion)isabout30V.CInshortcircuit(whentheelectrodecollideswiththeworkpiece),theshortcircuitcurrentI2shouldnotbetoolargetoavoiddamagetotheweldingmachine.DInordertoadapttodifferentweldingpartsanddifferentspecificationsofweldingrod,thesizeoftheweldingcurrentisrequiredtobeuniformandadjustableinanycase正确答案：ABC第15题Theoutputvoltageofthegeneratorisgenerallya().A3.15kVB6.3kVC10.5kVD16.75kV正确答案：ABC第16题Thebasicprincipleofthetransformeristheelectromagneticinduction第17题Undertheconditionofacertainmagneticfluxpotential,onlychangetheratioofthenumberofthesecondarywindingtoachievethepurposeofchangingtheoutputvoltageofthesecondarywinding.第18题Thereisonlymagneticcouplingbetweentheprimaryandsecondarywindings,andnoelectricdirectconnection第19题Whenusingthetransformer,itmustbenotedthat:becausethesecondarywindingcurrentofthevoltagetransformerisverylarge,soneverallowopencircuit;theprimarywindingturnsofthecurrenttransformerisverysmall,andtheturnsofthesecondarywindingismore,whichwillproduceahighinducedelectromotiveforceinthesecondarywinding,sothesecondarywindingofthecurrenttransformerdoesnotallowshortcircuit.第20题Themainprincipleofthecurrenttransformeristhataccordingtotheconvertereffectofthetransformer,inordertoreducethecurrent,N1<N2isrequired,andtheratedcurrentofthesecondarysideisgenerallystipulatedas10A.第1题Whenthethree-phaseasynchronousmotoradoptsstar-trianglevoltagestarting,itsstartingcurrentis()timesofthefullvoltagestartingcurrent.A1/2B1/3C1/4D1/5第2题Theratedpoweroftheasynchronousmotoris()power.AinputactivepowerBinputapparentpowerCelectromagneticpowerDthemechanicalpoweroutputbytherotorshaft第3题Inthemotorstate,theactualspeedoftheasynchronousmotor()issynchronousspeed.AlessthanBgreaterthanCequalDuncertain第4题ThemaximumallowableworkingtemperatureofGradeEinsulatingmaterialis:()A90°CB105°CC120°CD130°C第5题Theinstantaneousrotationrateofthethree-phaseasynchronousmotoris()An=0,s=1Bn=1,s=0Cn=1,s=1Dn=0,s=0第6题Inthefollowingspeedregulation,thegradedspeedregulationis:()AfrequencyconversionspeedregulationBvariablestagespeedregulationCchangethetransitionratespeedregulationDsteplessspeedregulation第7题Three-phasesynchronousmotorissuitablefor()AdonotrequirespeedadjustmentoccasionsBconstantspeedoccasionsCstartfrequentoccasionsDsmoothspeedadjustmentoccasions第8题Inordertochangethesteeringofthethree-phaseACasynchronousmotor,aslongastheoriginalphasesequenceA-B-Cischangedto:()AB-C-ABA-C-BCC-A-BDA-B-C第9题Themainandsecondarywindingsofthesingle-phaseasynchronousmotorshouldbedifferentinthespaceposition()A120°B180°C60°D90°第10题Athree-phasefour-poleasynchronousmotorwithratedrotationrateis0.04.Ifthepowerfrequencyis50Hz,thespeedofthemotoris().A1450r/minB1440r/minC960r/minD950r/min第11题Thecommonbrakingmethodsusedforthethree-phaseasynchronousmotorare().ApowergenerationBenergyconsumptionCelectricalDmachinery正确答案：CD第12题Thedebuggingmethodsofratcagethree-phaseACasynchronousmotorare()AvariablevoltagespeedregulationBvariablepolespeedregulationCfrequencyconversionspeedregulationDvariableratespeedregulation正确答案：CDB第13题Thecommonlyusedmouse-cagethree-phaseACsynchronousstartingmethodsare(

).AdirectstartBY-Δstep-downstartCautotransformerstep-downstartDseriesresistancestart正确答案：BC第14题Thestructureofthethree-phaseasynchronousmotorincludes()AstatorBairgapCrotorDmachineseat正确答案：ABC第15题Itcanbeviewedonthenameplateofthree-phasesynchronousmotor()ARatedpowerBratedvoltageCratedcurrentDratedspeed正确答案：ABCD第16题Inthethree-phaseasynchronousACmotor,themorethepolarlogarithmic,thehigherthemotorspeed.第17题TurnrateSisanimportantparametertoanalyzetheoperationperformanceoftheasynchronousmotor.Whenthefasterthemotorspeedis,thecorrespondingturnrateislarger.第18题Therotorrotationdirectionofthethree-phaseasynchronousmotoristhesameasthatofthestatorrotatingmagneticfield.第19题Thenameplateofthethree-phaseratcageasynchronousmotorindicates:"ratedvoltage380/220V,wiringY/△".Whenthepowersupplyvoltageis380V,thethree-phaseasynchronousmotorcanbestartedwithY-△step-down.第20题Single-phaseasynchronousmotorgenerallyadoptsstep-downandvariablepolefordebugging.Chapter3Testing第1题IntheDCmotor,thecurrentisDCwith(

)AMainpoleexcitationwindingBChangingpolewindingCArmaturewindingelementDArmaturecircuitatbothendsofthebrush第2题InthearmatureelementoftheDCmotor,thepotentialthathindersthecurrentchangeisdefinitely(

)AReactancepotentialBArmaturereactionpotentialCCommutatorpotentialDSyntheticpotential第3题ThemethodtodeterminewhethertheDCmotorisrunninginthegeneratorstateorthemotorstateisincluded()AComparisonofUandEasizesBComparisonofnoandnsizesCJudgebythepositiveandnegativeofPemDJudgebywhetherthearmatureisconnectedtotheDCpowersupply第4题RegardingthefunctionofthetransductoroftheDCmotor,itistruethat(

)AAutomaticchangethecurrentdirectionwhenthecoilplaneisparalleltothemagneticlineBWhenthecoilplaneisparalleltothemagneticsensorplane,changethecoilrotationdirectionautomaticallyCAutomaticchangeofthedirectionofthesensorlinewhenthecoilplaneisparalleltothesensorlineDAutomaticchangethedirectionofcurrentwhenthecoilplaneisperpendiculartotheinductionline第5题Inordertochangetherotationdirectionofthemotor,thefollowingmeasuresthatcanbetakenarecorrect:(

)AChangethesizeofthepowersupplyvoltageBChangethedirectionofthecurrentpassingthroughthecoilCChangethemagnitudeofthecurrentpassingthroughthecoilDAdjustthepositionofthetwomagneticpolesNandS,andadjustthepositiveandnegativepolesofthepowersupply第6题TheDCmotoroperateswithAconstanttorqueload.Ifitsexcitationcurrentisincreased,itselectromagnetictorquewillbe(

)AincreasedBunchangedCdecreasedDuncertain第7题Whentheelectromagnetictorqueofthemotorisgreaterthantheloadtorque,thepowerdraggingsystemisinthe(

)state.AUncertaintyBDecelerationoperationCConstantspeedoperationDAcceleration第8题IntheDCmotor,thecurrentisdchas(

)AmainmagneticpolewindingBreversingpolewindingCrmaturewindingelementDarmaturecircuitatbothendsofthebrush正确答案：AB第9题ThecommonlyusedelectricalbrakingmethodsforDCmotorare()AenergybrakeBreversebrakeCfeedbackbrakeDlockbrake正确答案：ABC第10题ThecommonlyusedspeedregulationmethodsfortheexcitationDCmotorare()AChangetheloadsizespeedregulationBStep-downspeedregulationCRotorloopstringresistancespeedregulationDToreducethemainmagneticfluxspeedregulation正确答案：BCD第11题ThepotentialandcurrentinthearmatureelementoftheDCmotorarebothDC.第12题ThereversingextremeattentionofDCmotoristoimprovethereversingdirectionofDCmotor.第13题BecausetheDCmotorarmatureistheDCpowersupply,theflowthroughthearmaturewindingelementmustbetheDCcurrent.第14题BecausethecasingoftheDCmotorisapartofthemainmagneticcircuitofthemotor,itismadeofcaststeelinsteadofcastiron.第15题BecausetheinstallationofreversingmagneticpolesisaneffectivemeasuretoimprovethedirectionofDCmotors,allDCmotorsequippedwithreversingmagneticpolescanhaveagoodchangingorientation.第16题TheelectromagnetictorqueoftheDCmotoristhedrivingtorque,so,whenthesteadystateoperation,thelargeelectromagnetictorquecorrespondingtotherotationspeedishigh.第17题HeexcitedDCmotortoreducethepowersupplyvoltagespeedregulationbelongstothewayofbalancebureauspeedregulation,soitcanonlydragtheconstanttorqueloadoperation.第18题ThesizeoftheinducedelectromotiveforceinaDCgeneratormainlydependsonthesizeoftheexternalcircuitload.第19题TheoutputpowerontheDCmotorshaftistheratedpowerofthemotor.Chapter4Testing第1题Forathree-phasesteppingmotorwith40rotor,astepAngleof1.5°shallbepoweredto()AsinglebeatsystemBdoublebeatsystemCsingleanddoublebeatsystemDsubdivisioncircuit第2题RegardingthestepAnglecharacteristicsofthesteppingmotor,itistruethat()Aforeachelectricalpulsesignal,thespatialangleoftherotoriscalledthestepangleBisproportionaltothenumberofrotorteethandinverselyproportionaltothenumberofrunningbeatsCinproportionaltothenumberofrotorteeth,andproportionaltothenumberofrunningbeatsDisproportionaltothenumberofrotorteethandisproportionaltothenumberofrunningbeats第3题ThefunctionrelationshipbetweentheelectromagnetictorqueandtheoutputspeedoftheDCservomotoriscalledits(

)AmechanicalpropertiesBergulatingcharacteristicCtorquefactorDSpeedcharacteristics第4题IntheACservomotor,theelectricAnglebetweenthecontrolwindingandtheexcitationwindingis()A60°B45°C0°D90°第5题TheDCspeedmeasuringgeneratorisoutputwiththespeed()AproportionalACvoltageBinverselyproportionalACvoltageCproportionalDCvoltageDinverseproportionalDCvoltage第6题Operationmodeofthree-phasesteppingmotorincludes(

)Athree-phasesinglethreebeatBthree-phasedoublethreebeatCfour-phasesinglefourbeatDtwo-phasesinglefourbeat正确答案：AB第7题Thereisafour-phaseeight-polereactivesteppingmotor,themotorrotortoothnumberis50,anditsstepdistanceAngleis()A1.8°B3.6°C2.7°D0.9°正确答案：AD第8题Themaintypesoflinearasynchronousmotorsare()AflatBtubeCarcDdisc正确答案：ABCD第9题ThecontrolmodeoftheACservomotorisprovidedwith()AamplitudecontrolBphasecontrolCcapacitorcontrolDresistancecontrol正确答案：ABC第10题Steppermotorcanbedividedinto()accordingtodifferentexcitationmodesAelectromagnetictypeBpermanentmagnettypeCreactivetypeDpermanentmagnetinductiontype正确答案：BCD第11题Thethree-phasereactivesteppingmotorcanincreasetheloadcapacitybyincreasingthenumberofpowerphases.第12题Thetorqueofthesteppingmotordecreasesasthefrequencyincreases.第13题Inprinciple,eachrotatingmotorhasacorrespondinglinearmotor.第14题Theprimaryandsecondarystagesoflinearmotorsaregenerallythesameaslong.第15题FortheACservomotor,changethecontrolvoltagetochangeitsspeedandsteering.第16题TheACservomotorcannotrotatewhenthecontrolvoltageiscancelled.第17题WhentheDCspeedmeasuringgeneratorisused,ifitexceedsthespecifiedmaximumspeedorfallsbelowthespecifiedminimumloadresistance,itwillhaveanimpactonitscontrolaccuracy.第18题Linearmotorisanelectricmachinethatrequiresanintermediateconversiondeviceforlinearmovement.第19题TheDCservomotorisdividedintotwobasicstructures:permanentmagnettypeandelectromagnetictype,amongwhichthepermanentmagnettypeDCservomotorcanberegardedastheexcitationtypeDCmotor.第20题Changethepowerorderofthestatorwindingofthesteppermotor,andcannotcontrolthepositiveandreverseofthemotor.Chapter5Testing第1题Manualswitchofelectricalapplianceis(

).AlowvoltagecircuitbreakeBelectricrelayCcontactorDcombinationswitch第2题Circuitbreakertimeofthemeltand().AtheelectriccurrentisdirectlyproportionalBtheelectriccurrentisinverselyproportionalCthesquareofthecurrentisproportionalDthesquareofthecurrentisinverselyproportional第3题Thecoilsuctioncurrentoftheovercurrentrelayshallbe(

)thereleasecurrentofthecoil.AgreaterthanBless-thanCequaltoDunidentified第4题ForACcontactors,ahighoperatingfrequencycancause（）.AironheartoverheatingBthecoilisoverheatedCmaincontactpointtooverheatDcontrolthecontactpointforoverheating第5题Accordingtotheprincipleofaction,（）isthemostwidelyusedrelay.AinductiontyperelayBphotoelectrictyperelayCelectromagneticrelayDpiezoelectricrelay第6题Volvoltagerelaycanbedividedinto()accordingtothesuctionvoltagerelativetoitsratedvoltage.AovervoltagerelayBundervoltagerelayCthermalrelayDthezero-voltagerelay正确答案：ABD第7题Whichofthefollowingarethemainorderappliances?AButtonBTravelswitchCUniversaltransferswitchDThermalrelay正确答案：ABC第8题Theairdampingtimerelayismainlycomposedof()AelectromagneticmechanismBfusepieceCworkingcontactDairchamber正确答案：ACD第9题TheratedvoltageratingoftheACcontactorcoilis(

)and380V.A36VB110VC127VD220V正确答案：ABCD第10题Contactwearofthecontactorisgenerallydueto().AcorewearBelectricalwearCcopperringfallingoffDmechanicalwear正确答案：BD第11题Lowvoltageswitchescanbeusedtodirectlycontrolthestart,stopandreversemotorofanycapacity.第12题Thebuttonswitchcanbeusedasalow-voltageswitch,tocompletethemaincircuitthroughmanualoperation.第13题Themainorderapplianceisthecontrolappliancethatsendsoutinstructionsorsignalsintheautomaticcontrolsystem.Becauseitisspeciallyordered,soitiscalledthemainorderofelectricalappliances.第14题Inadditiontotheon-offcircuit,thecontactoralsohastheshortcircuitandoverloadprotectionfunction.第15题ToohighortoolowvoltageoftheACcontactorwillcausethecoiloverheating.第16题Theinputsignaloftheintermediaterelayisthepoweronandpoweroffofthecoil.第17题Theknifeswitchcanbeusedinterchangeablyaslongasthevoltageisthesame.第18题Fusesareusedasshort-circuitprotectionandover-currentprotection.第19题Theactionvoltageofundervoltagerelayandzerovoltagerelayisthesame.第20题Allknifeswitcheshaveshort-circuitprotectiondevices.Chapter6Testing第1题ForcontactorKM1,contactorKM2requires（）AstringthenormallyopencontactsofKM2inthecoilloopofKM1BstringthenormallyclosedcontactsofKM2inthecoilloopofKM1CstringintotheconstantopencontactofKM1inthecoilloopofKM2DstringthenormallyclosedcontactsofKM1inthecoilloopofKM2第2题Thethree-phasecagemotoradoptsstar-trianglestep-downstarting,anduses()connectionmotorinnormaloperation.AdeltaBstarCbothDneitherisgood第3题Inthestar-triangularpressurereductioncircuit,thestarconnectionstartingvoltageisthetriangularconnectionvoltage(

)A1/3B1/2C1/4D1/6第4题Thetwocontactorsintheforwardandreverseoperationofthemotormustrealizeeachother(

)AmemoryBauto-lockCprohibitDinterlocking第5题ChangetherunningdirectionoftheACmotorandtakethewaytoadjustthepowersupply（

）AstatorstringresistanceBadjustthephaseorderofthethreephasesCadjustthephaseorderofthetwophasesDtherotorstringresistance第6题Thecommonelectricalbrakingmethodsofthree-phaseasynchronousmotorare()AseriesbrakingBdynamicbrakingCplugbrakingDantihypertensivebrake正确答案：BC第7题The()existsintheunidirectionalrotationstartcontrolcircuitoftheDCmotor.