毕业设计三相异步电动机外文翻译(精)

,,,,,,1nTemnS,Tem=f(s,,,,,,,,,(,,,,2,Y-D,,,Y-D,1/3,,l/k2(k,,,,SoftStarter,,,,,,,,,,3,,:Y-YYY-YD-YYY-YY,,,,,,,,,,,,,,,,(DC,(DC(AC,,(inverter,,Asynchronousmotorhasasimplestructure,reliableoperation,lowprice,convenientmaintenanceandaseriesofadvantages,therefore,asynchronousmotoriswidelyusedinelectricdrivesystem.EspeciallywiththedevelopmentofpowerelectronictechnologyandACdrivetechnologybecomesmoremature,greatlyimprovethespeedperformancemakestheasynchronousmotor.Atpresent,electricdriveasynchronousmotorhasbeenwidelyusedinvariousindustrialelectricalautomation.Themechanicalpropertiesofthree-phaseasynchronousmotorstarting,themainmotorstarting,braking,speedcontroltechnology.Themechanicalpropertiesof1three-phaseasynchronousmotorMechanicalcharacteristicsofthree-phaseasynchronousmotorisreferstotherelationshipbetweenthespeedofthemotorelectromagnetictorqueofNandTem.DuetothespeedofNandslipShaveacertainrelationship,sothemechanicalpropertiesarealsocommonlyusedTem=f(srepresentation.Electromagnetictorqueexpressionofthree-phaseasynchronousmotorhasthreeforms,namelyphysicalexpression,parametersandpracticalexpression.Physicalexpressionsreflectthephysicalnatureofelectromagnetictorqueofasynchronousmotor,theelectromagnetictorqueisgeneratedbythemainfluxandrotoractivecurrentinteraction.Parameterexpressionreflectstherelationshipbetweenparametersofelectromagnetictorqueandpowersupplyparametersandmotor,theexpressioncanbeusedtoinfluenceeasilyanalyzetheinfluenceofparametervariationontheelectromagnetictorqueandallkindsofhumancharacteristics.Practicalexpressionsinasimple,easytoremember,isoftenusedinengineeringcalculationintheformof.Themaximumtorqueofmotorandtorquearetwoimportantindexesreflectingtheoverloadcapacityofthemotorandstartingperformance,maximumtorqueandstarttorquemotoroverloadcapacityisbigger,stronger,betterstartingperformance.Themechanicalcharacteristicofthree-phaseasynchronousmotorisanonlinearcurve,undernormalcircumstances,withthemaximaltorque(orcriticalslipasacutoffpoint,thelinearsegmentforthestableoperationregion,whilethenonlinearsectionisnotstableoperatingregion.Hardcharacteristicislinearsegmentinherentmechanicalproperties,thenominaloperatingpointspeedslightlylowerthanthesynchronousspeed.Shapeparametersavailableexpressionsman-mademechanicalcharacteristiccurveanalysis,analysisthekeytograspthemaximumtorque,startingtorquevariationofcriticalslipandthethreewiththeparametersof.2three-phaseasynchronousmotorstartingThree-phaseasynchronousmotorwithsmallcapacitycanbeusedtodirectlystart,cagemotorwithlargecapacitycanadoptstep-downstart.Step-downstartintostatorresistanceorreactancestep-downstart,Y-Dstep-downstartandautotransformerstart.Thestatorresistanceormotorstep-downstart,startingcurrentvoltagerelationswithareduced,andthestartingtorquewiththesquareofthevoltageisreduced,itissuitableforthestartingload.OnlyapplicabletomotorstarttonormaloperationforthetriangleconnectionY-Dbuck,thestartingcurrentandstartingtorqueisreducedtodirectstartup1\/3,whichisalsosuitableforthestartingload.Autotransformerstart,startingcurrentandstartingtorqueisreducedtodirectstartupl\/k2(kistheselfcouplingtransformer,suitableforlargeloadstarting.Thewoundrotorasynchronousmotorwithrotorseriesresistanceorfrequencysensitiverheostatstarting,thestartingtorque,smallstartingcurrent,suitableforheavyloadstarting,largeasynchronousmotor.Thesoftstarterisanovelcontroldeviceformotormotorsoftstart,softstop,lightloadenergysavingandvariousprotectingfunctionsinone,calledSoftStarter.Themainstructureisconnectedinseriesbetweenthepowersupplyandthecontrolledmotorthree-phaseinverseparallelthyristoranditselectroniccontrolcircuit.Throughtheseriesofsoftstarterisconnectedbetweenthepowersupplyandthecontrolledmotor,indifferentways,itsinternalcontrolthyristorconductionangle,sothatthemotorinputvoltagefromzerotoapresetfunctiongraduallyrise,untiltheendofthemotorstart,givefullvoltage,namelysoftstart.Inthesoftstart-upprocess,startingtorquemotorspeedincreasesgradually,graduallyincreasing.Thesoftstarterisactuallyaregulator,forwhenthemotorisstarted,theoutputvoltagedoesnotchangethefrequencychange.3speedofthree-phaseasynchronousmotorControlmethodofthethree-phaseasynchronousmotorwithvariablespeed,variablespeedandvariableslipspeed.Thevariableslipratiocontrolincludesarotorwindingrotorasynchronousmotorseriesresistancespeedcontrol,cascadecontrolandbloodpressurecontrol.Variablespeedisbychangingthestatorwindingconnectionmodetochangethepolenumber,soastorealizethechangeofmotorspeed.Variablespeedisspeed-regulation,variablestatorwindingconnectionspeedofthreekinds:Y-YY,Y-,D-YYandYrun.TheY-YYconnectionisconstanttorquespeedcontrolmode,anothertwospeciesbelongtotheconstantpowercontrolmode.Variablepolespeed,shouldalsobeonthestatortwo-phasewiring,sothatwecanguaranteethespeedregulationmotorsteering.VariablefrequencyspeedcontrolisthemaindirectionofmodernACspeedregulationtechnology,itcanrealizesteplessspeedregulation,suitableforconstanttorqueandconstantpowerload.Woundrotorrotormotorseriesresistancespeedcontrolmethodissimple,easytoimp