资源描述:
《异步电动机起动的方法和问题.doc》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、英坎伎瞎任烫谳便戍硗INDUCTIONMOTORSTARTINGMETHODSANDISSUES淦婴抬鸬嵛坨联猓品呐Abstract-ManymethodscanbeusedtostartlargeACinductionmotors.Choicessuchasfullvoltage,reducedvoltageeitherbyautotransformerorWyes-Delta,asoftstarter,orusageofanadjustablespeeddrivecanallhavepotentialadvantagesandtradeoffs.Reducedvoltagesta
2、rtingcanlowerthestartingtorqueandhelppreventdamagetotheload.Additionally,powerfactorcorrectioncapacitorscanbeusedtoreducethecurrent,butcaremustbetakentosizethemproperly.Usageofthewrongcapacitorscanleadtosignificantdamage.Choosingtheproperstartingmethodforamotorwillincludeananalysisofthepowersys
3、temaswellasthestartingloadtoensurethatthemotorisdesignedtodelivertheneededperformancewhileminimizingitscost.Thispaperwillexaminethemostcommonstartingmethodsandtheirrecommendedapplications.鋈创邓厍唷嫉鼍煤踱箪IndexTerms:motorstarting.Reducedvoltagestartautotransformer,wyes-delta,powerfactorcorrection卅呲箨轳綮
4、渚绛脸粕涿I.INTRODUCTION峪耨陋僖尺褐郗畴赅顷Thereareseveralgeneralmethodsofstartinginductionmotors:fullvoltage,reducedvoltage,wyes-delta,andpartwindingtypes.Thereducedvoltagetypecanincludesolidstatestarters,adjustablefrequencydrives,andautotransformers.These,alongwiththefullvoltage,oracrossthelinestarting,giv
5、ethepurchaseralargevarietyofautomotiveswhenitcomestospecifyingthemotortobeusedinagivenapplication.Eachmethodhasitsownbenefits,aswellasperformancetradeoffs.Properselectionwillinvolveathoroughinvestigationofanypowersystemconstraints,theloadtobeacceleratedandtheoverallcostoftheequipment.蠃嬉瓯囵锣蝎蛄闲遇丿
6、Inorderfortheloadtobeaccelerated,themotormustgenerategreatertorquethantheloadrequirement.Ingeneraltherearethreepointsofinterestonthemotor'sspeed-torquecurve.Thefirstislocked-rotortorque(LRT)whichistheminimumtorquewhichthemotorwilldevelopatrestforallangularpositionsoftherotor.Thesecondispull-upt
7、orque(PUT)whichisdefinedastheminimumtorquedevelopedbythemotorduringtheperiodofaccelerationfromresttothespeedatwhichbreakdowntorqueoccurs.Thelastisthebreakdowntorque(BDT)whichisdefinedasthemaximumtorquewhichthemotorwilldevelop.Ifan