同步電動機外文翻譯文獻

PAGEPAGE1同步電動機外文翻譯文獻同步電動機外文翻譯文獻(文檔含中英文對照即英文原文和中文翻譯)SynchronousmotorAbstract：Inrecentdecades,withthepowerelectronics,microelectronicstechnologyandthedevelopmentofmoderncontroltheory,mediumandsmallpowermotorsintheindustrialandagriculturalproductionandpeople'sdailylivesareverybroadapplication.Particularlyinthetownshipenterprisesandhouseholdelectricalappliances,needalargenumberofmediumandsmall-powermotors.Becauseofthismotordevelopmentandwideapplication,itsuse,maintenanceandrepairworkhasbecomeincreasinglyimportant，Herearejustontheknowledgeofsynchronousmotor1.PrincipleofoperationInordertounderstandtheprincipleofoperationofasynchronousmotor,letusexaminewhathappensifweconnectthearmaturewinding(laidoutinthestator)ofa3-phasesynchronousmachinetoasuitablebalanced3-phasesourceandthefieldwindingtoaD.Csourceofappropriatevoltage.ThecurrentflowingthroughthefieldcoilswillsetupstationarymagneticpolesofalternateNorthandSouth.(forconvenienceletusassumeasalientpolerotor,asshowninFig.50).Ontheotherhand,the3-phasecurrentsflowinginthearmaturewindingproducearotatingmagneticfieldrotatingatsynchronousspeed.InotherwordstherewillbemovingNorthandSouthpolesestablishedinthestatorduetothe3-phasecurrentsi.eatanylocationinthestatortherewillbeaNorthpoleatsomeinstantoftimeanditwillbecomeaSouthpoleafteratimeperiodcorrespondingtohalfacycle.(afteratime=12f,wheref=frequencyofthesupply).LetusassumethatthestationarySouthpoleintherotorisalignedwiththeNorthpoleinthestatormovinginclockwisedirectionataparticularinstantoftime,asshowninFig50.ThesetwopolesgetattractedandFigure50:Forceofattractionbetweenstatorpolesandrotorpoles-resultinginproductionoftorqueinclockwisedirectiontrytomaintainthisalignment(asperLenz’slaw)andhencetherotorpoletriestofollowthestatorpoleastheconditionsaresuitablefortheproductionoftorqueintheclockwisedirection.Howevertherotorcannotmoveinstantaneouslyduetoitsmechanicalinertia,andsoitneedssometimetomove.Inthemeantime,thestatorpolewouldquickly(atimedurationcorrespondingtohalfacycle)changeitspolarityandbecomesaSouthpole。SotheforceofattractionwillnolongerbepresentandinsteadthelikepolesexperienceaforceofrepulsionasshowninFig.51.Inotherwords,theconditionsarenowsuitablefortheFigure51:Forceofrepulsionbetweenstatorpolesandrotorpoles-resultinginproductionoftorqueinanticlockwisedirectionproductionoftorqueintheanticlockwisedirection.EventhisconditionwillnotlastlongerasthestatorpolewouldagainchangetoNorthpoleafteratimeof12f.Thustherotorwillexperienceanalternatingforcewhichtriestomoveitclockwiseandanticlockwiseattwicethefrequencyofthesupply,i.e.atintervalscorrespondingto12fseconds.Asthisdurationisquitesmallcomparedtothemechanicaltimeconstantoftherotor,therotorcannotrespondandmoveinanydirection.Therotorcontinuestobestationaryonly.Onthecontraryiftherotorisbroughttonearsynchronousspeedbysomeexternalmeanssayasmallmotor(knownasponymotor-whichcouldbeaD.CorACinductionrotor)mountedonthesameshaftasthatoftherotor,therotorpolesgetlockedtotheunlikepolesinthestatorandtherotorcontinuestorunatthesynchronousspeedevenifthesupplytotheponymotorisdisconnected.Thusthesynchronousrotorcannotstartrotatingonitsownorusuallywesaythatthesynchronousrotorhasnostartingtorque.So,somespecialprovisionhastobemadeeitherinsidethemachineoroutsideofthemachinesothattherotorisbroughttonearaboutitssynchronousspeed.Atthattime,ifthearmatureissuppliedwithelectricalpower,therotorcanpullintostepandcontinuetooperateatitssynchronousspeed.Someofthecommonlyusedmethodsforstartingsynchronousrotoraredescribedinthefollowingsection.2.MethodsofstartingsynchronousmotorBasicallytherearethreemethodsthatareusedtostartasynchronousmotor:?Toreducethespeedoftherotatingmagneticfieldofthestatortoalowenoughvaluethattherotorcaneasilyaccelerateandlockinwithitduringonehalf-cycleoftherotatingmagneticfield’srotation.Thisisdonebyreducingthefrequencyoftheappliedelectricpower.Thismethodisusuallyfollowedinthecaseofinverter-fedsynchronousmotoroperatingundervariablespeeddriveapplications.?Touseanexternalprimemovertoacceleratetherotorofsynchronousmotorneartoitssynchronousspeedandthensupplytherotoraswellasstator.Ofcoursecareshouldbetakentoensurethatthedirectionofrotationoftherotoraswellasthatoftherotatingmagneticfieldofthestatorarethesame.Thismethodisusuallyfollowedinthelaboratory-thesynchronousmachineisstartedasageneratorandisthenconnectedtothesupplymainsbyfollowingthesynchronizationorparallelingprocedure.Thenthepowersupplytotheprimemoverisdisconnectedsothatthesynchronousmachinewillcontinuetooperateasamotor.?Tousedamperwindingsoramortisseurwindingsiftheseareprovidedinthemachine.Thedamperwindingsoramortisseurwindingsareprovidedinmostofthelargesynchronousmotorsinordertonullifytheoscillationsoftherotorwheneverthesynchronousmachineissubjectedtoaperiodicallyvaryingload.Eachofthesemethodsofstartingasynchronousmotoraredescribedbelowindetail.2.1MotorstartingbyreducingthesupplyFrequencyIftherotatingmagneticfieldofthestatorinasynchronousmotorrotatesatalowenoughspeed,therewillbenoproblemfortherotortoaccelerateandtolockinwiththestator’smagneticfield.Thespeedofthestatormagneticfieldcanthenbeincreasedtoitsratedoperatingspeedbygraduallyincreasingthesupplyfrequencyfuptoitsnormal50or60Hzvalue.Thisapproachtostartingofsynchronousmotorsmakesalotofsense,butthereisabigproblem:Wherefromcanwegetthevariablefrequencysupply?Theusualpowersupplysystemsgenerallyregulatethefrequencytobe50or60Hzasthecasemaybe.However,variable-frequencyvoltagesourcecanbeobtainedfromadedicatedgeneratoronlyintheoldendaysandsuchasituationwasobviouslyimpracticalexceptforveryunusualorspecialdriveapplications.Butthepresentdaysolidstatepowerconvertersofferaneasysolutiontothis.Wenowhavetherectifier-inverterandcycloconverters,whichcanbeusedtoconvertaconstantfrequencyACsupplytoavariablefrequencyACsupply.Withthedevelopmentofsuchmodernsolid-statevariable-frequencydrivepackages,itisthuspossibletocontinuouslycontrolthefrequencyofthesupplyconnectedtothesynchronousmotorallthewayfromafractionofahertzuptoandevenabovethenormalratedfrequency.Ifsuchavariable-frequencydriveunitisincludedinamotor-controlcircuittoachievespeedcontrol,thenstartingthesynchronousmotorisveryeasy-simplyadjustthefrequencytoaverylowvalueforstarting,andthenraiseituptothedesiredoperatingfrequencyfornormalrunning.Whenasynchronousmotorisoperatedataspeedlowerthantheratedspeed,itsinternalgeneratedvoltage(usuallycalledthecounterEMF)EA=Kwillbesmallerthannormal.Assuchtheterminalvoltageappliedtothemotormustbereducedproportionallywiththefrequencyinordertokeepthestatorcurrentwithintheratedvalue.Generally,thevoltageinanyvariable-frequencypowersupplyvariesroughlylinearlywiththeoutputfrequency.2.2MotorStartingwithanExternalMotorThesecondmethodofstartingasynchronousmotoristoattachanexternalstartingmotor(ponymotor)toitandbringthesynchronousmachinetonearaboutitsratedspeed(butnotexactlyequaltoit,asthesynchronizationprocessmayfailtoindicatethepointofclosureofthemainswitchconnectingthesynchronousmachinetothesupplysystem)withtheponymotor.Thentheoutputofthesynchronousmachinecanbesynchronizedorparalleledwithitspowersupplysystemasagenerator,andtheponymotorcanbedetachedfromtheshaftofthemachineorthesupplytotheponymotorcanbedisconnected.OncetheponymotoristurnedOFF,theshaftofthemachineslowsdown,thespeedoftherotormagneticfieldBRfallsbehindBnet,momentarilyandthesynchronousmachinecontinuestooperateasamotor.Assoonasitbeginstooperatesasamotorthesynchronousmotorcanbeloadedintheusualmannerjustlikeanymotor.Thiswholeprocedureisnotascumbersomeasitsounds,sincemanysynchronousmotorsarepartsofmotor-generatorsets,andthesynchronousmachineinthemotor-generatorsetmaybestartedwiththeothermachineservingasthestartingmotor.Moreover,thestartingmotorisrequiredtoovercomeonlythemechanicalinertiaofthesynchronousmachinewithoutanymechanicalload(loadisattachedonlyafterthesynchronousmachineisparalleledtothepowersupplysystem).Sinceonlythemotor’sinertiamustbeovercome,thestartingmotorcanhaveamuchsmallerratingthanthesynchronousmotoritisgoingtostart.Generallymostofthelargesynchronousmotorshavebrushlessexcitationsystemsmountedontheirshafts.Itisthenpossibletousetheseexcitersasthestartingmotors.Formanymedium-sizetolargesynchronousmotors,anexternalstartingmotororstartingbyusingtheexcitermaybetheonlypossiblesolution,becausethepowersystemstheyaretiedtomaynotbeabletohandlethestartingcurrentsneededtousethedamperwinding.Motorfromthedevelopmentsincetheadventofgenerationsofproductsareallaroundthebasicprincipleofthedevelopment,howtorunandmaintainthemainmotoristhemostimportanttaskweare.MotorinChina'seconomicdevelopmentplayavitalrolein,alongwithChina'saccessiontoWTO,theindustryfacedNationalMotorsenormousinternationalcompetitivepressuresandchallengesarebecomingmoreintensified.Tosaveenergyandprotectthelocalenvironment,highefficiencymotoristheinternationaldevelopmenttrend.Itwouldappear,istopromotethehigh-efficiencymotorisnecessary.From：Corpsfrom2005Sichuansynchronousmotorworks同步電動機摘要：近幾十年來，隨著電力電子技術(shù)、微電子技術(shù)及現(xiàn)代控制理論的發(fā)展，中、小功率電動機在工農(nóng)業(yè)生產(chǎn)及人們的日常生活中都有極其廣泛的的應(yīng)用。特別是在鄉(xiāng)鎮(zhèn)企業(yè)及家用電器中，更需要有大量的中、小功率電動機。由于這種電動機的發(fā)展及廣泛的應(yīng)用，它的使用、保養(yǎng)和維護工作也越來越重要，下面就介紹關(guān)于同步電動機的相關(guān)知識。為了了解一個同步電動機的工作原理，讓我們研究這是如何發(fā)生的，如果我們連接的電樞繞組（在定子里闡述）是3相同步機合適的平衡3相電源和勵磁繞組的D.C適當?shù)碾妷?。目前，通過場線圈流動將替代固定南北磁極,另一方面，3相電流在電樞繞組產(chǎn)生旋轉(zhuǎn)磁場的同步轉(zhuǎn)速旋轉(zhuǎn)流動。換言之在移動中的任何位置定子由于有三相電流，建立南北兩極將在一定的時間并即時北極將成為一段時間后1南極期間相應(yīng)的半周期（經(jīng)過一段時間=1/2f，其中f=頻率的供應(yīng)）讓我們假設(shè)，固定南極轉(zhuǎn)子與定子在北極順時針方向排列正以特定時刻的時間，部隊之間定子，轉(zhuǎn)子極-在生產(chǎn)中的吸引力造成的扭矩順時針方向努力維持這個路線（根據(jù)楞次定律）因此轉(zhuǎn)子極試圖按定子極作為條件的扭矩順時針方向生產(chǎn)。不過，轉(zhuǎn)子不能即時移動，由于它的機械慣性，因此需要某個移動來執(zhí)行。與此同時，定子極會很快（持續(xù)時間相應(yīng)的半周期）改變其極性，成為南極。因此，引力將不再存在，而是像極經(jīng)歷一個斥力，與定子磁極，轉(zhuǎn)子磁極斥力-生產(chǎn)中產(chǎn)生的扭矩在逆時針的方向。生產(chǎn)的扭矩在逆時針的方向。即使是這種情況不會持續(xù)作為定子極長將再次改變北極后時間。因此，轉(zhuǎn)子將體驗交替的力量，試圖提出相應(yīng)的時間間隔為1秒，順時針和逆時針的兩倍供應(yīng)，即頻率。隨著這一期限是非常小的機械相比，轉(zhuǎn)子時間常數(shù)，轉(zhuǎn)子無法響應(yīng)和向任何方向移動。轉(zhuǎn)子繼續(xù)平穩(wěn)。相反，如果轉(zhuǎn)子所帶來的一些外部手段來接近同步轉(zhuǎn)速說，小馬達（稱為小馬電機可在轉(zhuǎn)導(dǎo)轉(zhuǎn)子）一直流或交流上作為轉(zhuǎn)子，同一軸上的轉(zhuǎn)子磁極被鎖定在不同的定子和轉(zhuǎn)子磁極繼續(xù)運行在同步轉(zhuǎn)速，即使到小馬汽車供應(yīng)中斷。因此，同步轉(zhuǎn)子無法啟動自身旋轉(zhuǎn)或通常我們說，沒有同步轉(zhuǎn)子起動轉(zhuǎn)矩。因此，一些特殊的規(guī)定，必須內(nèi)作出任何機器或機器的外面，使轉(zhuǎn)子提請有關(guān)其同步轉(zhuǎn)速附近。當時，如果電樞與電力供應(yīng)的轉(zhuǎn)子拉入一步，將要繼續(xù)運轉(zhuǎn)其同步的速度。常用下面描述的方法啟動同步電動機。2.同步電動機啟動方法基本上有三個用來同步電動機啟動方法●要減少定子旋轉(zhuǎn)磁場速度足夠低的價值，轉(zhuǎn)子可以輕松地加速并鎖定在與它在1個半的旋轉(zhuǎn)磁場的旋轉(zhuǎn)周期。這是通過減少電力的使用頻率。這種方法通常遵循的逆變器的情況饋變速驅(qū)動下的同步電動機運行的應(yīng)用程序?！褚褂靡粋€外部的主要驅(qū)動者，加快同步電機轉(zhuǎn)子附近的同步速度，然后在供應(yīng)的轉(zhuǎn)子和定子。當然，應(yīng)采取確保轉(zhuǎn)子的旋轉(zhuǎn)方向，以及這對定子旋轉(zhuǎn)磁場是相同的。這種方法通常是遵循該實驗室的同步電機啟動發(fā)生器和一個連接的應(yīng)用程序，然后按照同步或平行的程序供應(yīng)電源。那么電源的主要驅(qū)動者被斷開，使同步電機將繼續(xù)作為一個發(fā)動機?！褚褂米枘崂@組