关于异步电机的文献翻译

外文资料Onthethree-phaseasynchronousmotorphaseprotectionAbstract：Three-phaseasynchronousmotorburntphaseupandrunning.Designedthreekindsofphaseprotectioncircuitforthesereasons,analysisoftheworksandtheadvantagesanddisadvantagesofthethreekindsofprotectioncircuits,giventhelackofprotectioncontrolcircuit.Keywords:Motor；phase；controlcircuit；protectioncircuit；advantagesanddisadvantages1IntroductionHighthefailurerateoftheinductionmotor,inadditiontomechanicalreasons,themostimportantfactorintheelectricalaspectsofthethree-phasemotormissingphaseupandrunning.Asnotedinthemotorprinciplephasetostartandrunwhenthethree-phasemotor,thestatorwindingscouldnotproducearotatingmagneticfield,therotationtorqueiszero,themotorvibrationwithoutrotation.Motorpowertothetwo-phasestarts,infact,intheshort-circuitstate,anditsshort-circuitcurrentis0.866timesthestartingcurrentforthethree-phasestart,andthegeneralasynchronousmotorstartingcurrentfortheratedcurrentof4to7timesthemotorintothetwo-phasepower-up,whichisequivalenttotwo-phaseshortcircuitcurrentoftheratedcurrentof3.464~6.062timesabovecurrentsmallstartupcurrent,muchlargerthanthemotorratedcurrent,andthusthemotorphasetostartandrun,easytoburnoutthemotor,thefollowingadditionalrelaysandbuttonlackofprotectionwhenthemotorupandrunning..2AsimplemotorphaselossprotectioncircuitsThecircuitshowninFigure1inthecontrolcircuitofanACcontactorKMbie,inL1,L2ofthetwophasesofaccessKMbelectromagneticcoil,andit'sonenormallyopencontactKMbconnectedinseriesinthecontrolcircuit.2.1PhaseProtectionPrincipleWhenclosedtheknifeswitchQS,thenconnectedtotheL1,L2,betweentwo-phaseACcontactorKMbelectromagneticcoilisenergizedtopullthenormallyopencontactsconnectedinthecontrolloopKMbclosed,startthemotortodopreparation.WhenyoupressthestartbuttonSB2,thecircuitconnectedtothemotorrotation.Ifthemotorstartbeforethepowerphase,thetotalthree-phasepowercontrolcircuitaccess,regardlessofthelackofanyphasepowersupplyL1,L2,L3,three-phase,twosolenoidcoilinthecontrolloop,onecannotattractthearmatureleavingthecircuitclosed,sothemotordoesnotstart.Whenthemotorisrunning,onephasepower-down,suchasthelackofphaseL1orL3,lostpowerACcontactorKMbelectromagneticcoil,connectedinthecontrolloopKMbdisconnect,ACcontactorKMlossofpower,self-lockingcontactisopen,themaincontactisdisconnected,themotorstops.SuchaslackoftheL2phase,KMbenergizedclosed,buttheACcontactorcoilKMlossofpower,self-lockingcontactsdisconnectthemaincontactisopen,themotorstopsrotating.Thebiggestadvantageofthecircuitisthethree-phasepowersupplyandtheintroductionofthecontrolcircuit.3AcoilgroundedmotorphaselossprotectioncircuitsShowninFigure2,theinstallationofthemotorcontrolcircuitofanACcontactororintermediaterelayKM2theKM2acrossoutsidethemaincontactorKMcoiltwo-phasetoanotherphaseandgroundPE.ItshouldbeexplainedKM2coilisreasonableConnectoneendoftheground,theansweriscertainlyfeasiblefromasecuritystandpoint,theL3phaselineisafterKM2coilafterreceivingtheground,soasnottocausedirectgroundingoftheL3phaselineshort-circuitaccident.TheKM2coilgroundedatoneendofthepersonalsecuritysituationissimilartotheprotectionmustbegroundedatoneendofthevoltagetransformerorcurrenttransformerandthecore.Note,however,KM2beforebesuretosetfusesFU2-3.3.1PhaseProtectionPrinciple①IfthefuseFU1-1orFU1-2(L1orL2phase)theKM2coilchargedKMcoilcharged,themotorlinepowerfailure.②IftheFU1-3fuseorL3phasetheKM2coilisnotcharged,resultinginKMcoildisconnected,themotorpower.Motorbeforethestartofphaseorintheoperationphaselossprotectionprinciplesarethesame.3.2oftheadvantagesofthecircuitThecircuitisnotonlyrealizedthemotorintothelineU,V,Wphaseprotection,butalsothepowercordL1,L2,L3,phaseofprotection.Protectioncircuitissimpleandreasonablemodificationeasy,automaticcontrolcircuitforavarietyofmotorcontroltoreach.4AnevermissingphasetostartandrunthecontrolcircuitNeverphasestartupandoperationcontrolcircuitshowninFigure3bysimplyaddingafewintermediaterelayandthewiringofthecircuitinFigure3,wecanguaranteethatthethree-phasemotorneverphaseKai4.1Workingprinciple①startprinciple:PressthestartbuttonSB1,theintermediaterelayKA1coilisenergizedtopullatthesametimebyKA1contactstomaketheintermediaterelayKA2electriccoilandpull,pullKMmaincontacts,motorterminalsU,V,Wisenergized,themotorstartsrunning.KMauxiliarycontactsintermediaterelayKA3coilisenergizedtopull,theKA3contactbuttonSB2maincontactorcoilpowertomaintain,KMcoilpowersupplypathfortheUterminal-SB2,-KA3contact,-KMcoil-FRtouchpoint-FU2-VterminalSB1reset,KA1andKA2release,themaincontactorKMstillpull,sothatthemotorstartrunning.②downtimeprinciple:SB2,pressthestopbutton,themaincontactortheKMcoilpowerpathiscutoff,thereleaseoftheKM.KMauxiliarycontactstoKA3coillossofpower,theKA3release.EvenifSB2resetduetoKA3contactsdisconnected,theKMcannotpullthemotortostoprunning.4.2NevermissingphaseWorkingprinciple①nevermissingphasestart:thecircuitinFigure3,ifthelackoftheL1,L2,anyonephase,pressSB1,theintermediaterelayKA1coilvoltage,theKA1donotpull,youcannotcompletemotorstarting;ifthelackofL3phasepresstheSB1,despitetheKA1pull,butnotKA2pullKA2coilvoltage,themotorcannots