英文翻譯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:vliftspeed（m/s）Ddiameteroftractionmachine（m）Nmotorspeed(r/min)ytractionratio（tractionmode）jgearratioForexample:Giventhefactthatsheavediameteroftractionsheaveis0.8m,motorspeedis1500r/min,reductionratiois53:3,gearratiois2:1,whatisliftspeed?D=0.8m，N=1000r/min,y=2/1,j=53/3Fromthegivenconditions,welearnthatD=0.8m，N=1000r/min,y=2/1,j=53/3.Accordingtoabovementionedformula,wecancalculatethat：Aspowerproviderforliftmovement,tractions/75m.1353126014800.814.360jyiiDNvmachinefeaturescomplicatedoperationprocedures,amongwhichisinvolvedwithfrequentstart-up,brake,clockwiseandcounterclockwiserotation.Duetoconstantlychangingload,workingstatusoftractionmachineischaracteristicofrepetitiousshorttimeoperation,electricalcontrolandregeneration.Therefore,withlowstart-upcurrent,largestart-uptorque,mechanicallyrigidfeaturesandlownoise,itisrequiredthattractionmachineshouldnotonlybeadaptedforfrequentstart-up,brake,butalsostartupandfunctionwellwhenpoweroltagefluctuateswithinnormalrange.Beingspecialmachineforlift,tractionmachineischaracteristicofcomplicatedoperation,whoseHpcanbecalculatedthroughfollowingformula:Where:PshaftHpoftractionmachine(kw)Gratedloadofcar(kg)offsettingcoefficienttotalmechanicalefficiencyvliftspeed（m/s）Forliftwithgearedtractionmachine,ifwormgearisArchimedestype,totalmechanicalefficiencyrangesfrom0.5to0.55；forliftwithgearlesstractionmachine,totalmechanicalefficiencyrangesfrom0.75to0.8.Forexample:ForanACtwo-speedliftwhoseratedloadis2000kgandratedspeedis0.5m/s,wormgearisArchimedestype,ratedspeedofmotoris960r/min,whatishpofmotor?AccordingtoG=2000kg,=0.5，v=0.5m/s，=0.5,wecancalculatebyinputtinggivenvalues.GearedtractionmachineisclassifiedintoACandDCtypes.W191tractionmachineisACfrequency-variablemotor.Currently,besideswormgearedmachine,bevelandstargearedmachinesarealsoavailable.Gearlesstractionmachine9.8kw0.51020.50.5)(12000102)vG(1PGearlesstractionmachineisusedinliftswithspeedofmorethan2.0m/s.Withtractionsheavefixedinmotorshaft,thistractionmachineissimpleinstructurewithoutanymechanicalgearedmachine.Speciallydesignedformanufacturedforlift,tractionmotorissuitableforliftoperationandclassifiedintospeed-variableDCandfrequency-variableACmotor.Infigure2-2isshownanACfrequency-variablegearlesstractionmachine.Thismachineneedsmuchmorebraketorquethangearedmachinewhenitismanufactured,therefore,itneedsaratherbiggerbrake.Gearlesstractionmachineismoreoftenthannotusedincompoundwindingdrive,therefore,forceappliedontractionsheave,compoundwindingsheaveandbearismuchlargerthanthatontractionmachine；correspondingshaftisoflongerdiameter.Withnogearedmachine,ithaslongerusagelife.PermanentmagnetsynchronousgearlesstractionmachineWecanthelpmentioningtheapplicationofpermanentmagnetsynchronousgearlesstractionmachineinlift.Withtherapiddevelopmentoftractiontechnologyinlift,moreandmoreliftswithoutmachineroomareadoptingpermanentmagnetsynchronousgearlesstrailingtechnology.Forliftswithoutmachineroom,thereisnoneedtoenlargewelldimensions,simplifyingandbeautifyingconstruction,savingcost,especiallytheapplicationvalueofsuchliftsisenhancedby圖2-2無齒輪曳引機(jī)DAF290Figure2-2GearlesstractionmachineDAFBrakeMotorTractionsheavelownoise,highefficiencyandpowereconomization,andwhatdistinguishesliftswithoutmachineroomfromothersliesinthepermanentmagnetsynchronousgearlesstractionmachine.Infigure2-3isshownPMS425ALpermanentmagnetsynchronousgearlesstractionmachineusedinThyssensliftswithoutmachineroom.Thetractionmachineisflatinstructure,soonlyaverysmallspaceisneededbetweenwellwallsandcartocompleteinstallation.Withgearlessdesign,motortorquedirectlypassesontotractionsheave,combinedwithstaticfrictionofnon-decelerationpart,drivingefficiencycanexceed90%；besides,duetolowrotationspeed,tractionmachinerunswithlownoiseandisfreefromvibration.Thetractionmachinehastwomechano-electronicbrakes,therefore,theotherbrakecanprovidesufficientjerkforcetostopcarwith100%ratedloadifonebrakefailstofunction.Characteristicsofpermanentmagnetsynchronousgearlesstractionmachine:Comfortableriding；Lowrunningnoise；Highefficiency；Lowloadofelectricaldevices；Convenientandreliablemaintenance,withoutneedtochangeoil,eliminatingoilleakage；Easytoreplaceassembly,withexteriorbrake；Widerangeofsettingandinstallationintractionmachine.Comp