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英文翻译TractionmachineAspowerproviderforlift,tractionmachine,alsocalledmainmachine,iscomposedofmotor,brake,gearedmachineandseat.Itisadrivetomakecarmovebymeansofthefrictionbetweentractionropeandsheave.Accordingtowhetherthegearedmachineisprovidedornot,itisclassifiedintogearedandgearlesstypes.GearedtractionmachineGearedtractionmachineiswidelyusedincargolift,passengerliftandserviceliftwithspeedofnotmorethan2.0m/s.Toreduceworkingnoiseandenhancestability,wormgearisnormallyusedasgeareddrive.Suchmachineiscomposedofmotor,worm,gear,brake,ropeandseat,asshownisfigure2-1.Mainparameters,suchasliftloadandspeedaredeterminedbyHpandspeedoftractionmachine,wormandgearnumbers,gearratio,diameteroftractionmachine,ropegroovesandtractionratio(tractionmode).Forliftsadoptinggearedtractionmachine,therelationshipbetweenliftspeed,tractiongearratio,tractionmachinediameter,tractionmotorspeedisasfollows:Where:v—liftspeed（m/s）D—diameteroftractionmachine（m）N—motorspeed(r/min)ίy—tractionratio（tractionmode）ίj—gearratioForexample:Giventhefactthatsheavediameteroftractionsheaveis0.8m,motorspeedis1500r/min,reductionratiois53:3,gearratiois2:1,whatisliftspeed?D=0.8m，N=1000r/min,ίy=2/1,ίj=53/3Fromthegivenconditions,welearnthatD=0.8m，N=1000r/min,ίy=2/1,ίj=53/3.Accordingtoabovementionedformula,wecancalculatethat：Aspowerproviderforliftmovement,tractionmachinefeaturescomplicatedoperationprocedures,amongwhichisinvolvedwithfrequentstart-up,brake,clockwiseandcounterclockwiserotation.Duetoconstantlychangingload,workingstatusoftractionmachineischaracteristicofrepetitiousshorttimeoperation,electricalcontrolandregeneration.Therefore,withlowstart-upcurrent,largestart-uptorque,mechanicallyrigidfeaturesandlownoise,itisrequiredthattractionmachineshouldnotonlybeadaptedforfrequentstart-up,brake,butalsostartupandfunctionwellwhenpoweroltagefluctuateswithinnormalrange.Beingspecialmachineforlift,tractionmachineischaracteristicofcomplicatedoperation,whoseHpcanbecalculatedthroughfollowingformula:Where:P—s
