同步电动机外文翻译文献.docx
- 文档编号:398322
- 上传时间:2022-10-09
- 格式:DOCX
- 页数:7
- 大小:18.74KB
同步电动机外文翻译文献.docx
《同步电动机外文翻译文献.docx》由会员分享,可在线阅读,更多相关《同步电动机外文翻译文献.docx(7页珍藏版)》请在冰豆网上搜索。
同步电动机外文翻译文献
同步电动机外文翻译文献
(文档含中英文对照即英文原文和中文翻译)
Synchronousmotor
Abstract:
Inrecentdecades,withthepowerelectronics,microelectronicstechnologyandthedevelopmentofmoderncontroltheory,mediumandsmallpowermotorsintheindustrialandagriculturalproductionandpeople'sdailylivesareverybroadapplication.Particularlyinthetownshipenterprisesandhouseholdelectricalappliances,needalargenumberofmediumandsmall-powermotors.Becauseofthismotordevelopmentandwideapplication,itsuse,maintenanceandrepairworkhasbecomeincreasinglyimportant,Herearejustontheknowledgeofsynchronousmotor
1.Principleofoperation
Inordertounderstandtheprincipleofoperationofasynchronousmotor,letusexaminewhathappensifweconnectthearmaturewinding(laidoutinthestator)ofa3-phasesynchronousmachinetoasuitablebalanced3-phasesourceandthefieldwindingtoaD.Csourceofappropriatevoltage.ThecurrentflowingthroughthefieldcoilswillsetupstationarymagneticpolesofalternateNorthandSouth.(forconvenienceletusassumeasalientpolerotor,asshowninFig.50).Ontheotherhand,the3-phasecurrentsflowinginthearmaturewindingproducearotatingmagneticfieldrotatingatsynchronousspeed.InotherwordstherewillbemovingNorthandSouthpolesestablishedinthestatorduetothe3-phasecurrentsi.eatanylocationinthestatortherewillbeaNorthpoleatsomeinstantoftimeanditwillbecomeaSouthpoleafteratimeperiodcorrespondingtohalfacycle.(afteratime=1
2f,wheref=frequencyofthesupply).LetusassumethatthestationarySouthpoleintherotorisalignedwiththeNorthpoleinthestatormovinginclockwisedirectionataparticularinstantoftime,asshowninFig50.ThesetwopolesgetattractedandFigure50:
Forceofattractionbetweenstatorpolesandrotorpoles-resultinginproductionoftorqueinclockwisedirectiontrytomaintainthisalignment(asperLenz’slaw)andhencetherotorpoletriestofollowthestatorpoleastheconditionsaresuitablefortheproductionoftorqueintheclockwisedirection.Howevertherotorcannotmoveinstantaneouslyduetoitsmechanicalinertia,andsoitneedssometimetomove.Inthemeantime,thestatorpolewouldquickly(atimedurationcorrespondingtohalfacycle)changeitspolarityandbecomesaSouthpole。
SotheforceofattractionwillnolongerbepresentandinsteadthelikepolesexperienceaforceofrepulsionasshowninFig.51.Inotherwords,theconditionsarenowsuitablefortheFigure51:
Forceofrepulsionbetweenstatorpolesandrotorpoles-resultinginproductionoftorqueinanticlockwisedirectionproductionoftorqueintheanticlockwisedirection.EventhisconditionwillnotlastlongerasthestatorpolewouldagainchangetoNorthpoleafteratimeof1
2f.Thustherotorwillexperienceanalternatingforcewhichtriestomoveitclockwiseandanticlockwiseattwicethefrequencyofthesupply,i.e.atintervalscorrespondingto1
2fseconds.Asthisdurationisquitesmallcomparedtothemechanicaltimeconstantoftherotor,therotorcannotrespondandmoveinanydirection.Therotorcontinuestobestationaryonly.
Onthecontraryiftherotorisbroughttonearsynchronousspeedbysomeexternalmeanssayasmallmotor(knownasponymotor-whichcouldbeaD.CorACinductionrotor)mountedonthesameshaftasthatoftherotor,therotorpolesgetlockedtotheunlikepolesinthestatorandtherotorcontinuestorunatthesynchronousspeedevenifthesupplytotheponymotorisdisconnected.
Thusthesynchronousrotorcannotstartrotatingonitsownorusuallywesaythatthesynchronousrotorhasnostartingtorque.So,somespecialprovisionhastobemadeeitherinsidethemachineoroutsideofthemachinesothattherotorisbroughttonearaboutitssynchronousspeed.Atthattime,ifthearmatureissuppliedwithelectricalpower,therotorcanpullintostepandcontinuetooperateatitssynchronousspeed.Someofthecommonlyusedmethodsforstartingsynchronousrotoraredescribedinthefollowingsection.
2.Methodsofstartingsynchronousmotor
Basicallytherearethreemethodsthatareusedtostartasynchronousmotor:
•Toreducethespeedoftherotatingmagneticfieldofthestatortoalowenoughvaluethattherotorcaneasilyaccelerateandlockinwithitduringonehalf-cycleoftherotatingmagneticfield’srotation.Thisisdonebyreducingthefrequencyoftheappliedelectricpower.Thismethodisusuallyfollowedinthecaseofinverter-fedsynchronousmotoroperatingundervariablespeeddriveapplications.
•Touseanexternalprimemovertoacceleratetherotorofsynchronousmotorneartoitssynchronousspeedandthensupplytherotoraswellasstator.Ofcoursecareshouldbetakentoensurethatthedirectionofrotationoftherotoraswel
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 同步电动机 外文 翻译 文献
![提示](https://static.bdocx.com/images/bang_tan.gif)