資源描述：
《直流電機速度控制.doc》由會員上傳分享，免費在線閱讀，更多相關內容在教育資源-天天文庫。
1、輟悉報蜣墑炱澡度髏工郛呦熟現(xiàn)SpeedControlofDCMotor氡町疔嗒堙昆懂能佃贛彎鉞甲蹋RegulatorSystems圇櫚倨贏鵲吁賁購燼萃笆璜舌嵩Aregulatorsystemisonewhichnormallyprovidesoutputpowerinitssteady-stateoperation.避舐有痂杖倚求皆垅澹杜撕砧睫Forexample,amotorspeedregulatormaintainsthemotorspeedataconstantvaluedespitevariationsin
2、loadtorque.Eveniftheloadtorqueisremoved,themotormustprovidesufficienttorquetoovercometheviscousfrictioneffectofthebearings.Otherformsofregulatoralsoprovideoutputpower;Atemperatureregulatormustmaintainthetemperatureof,say,anovenconstantdespitetheheatlossintheove
3、n.Avoltageregulatormustalsomaintainmustoutputvoltageconstantdespitevariationintheloadcurrent.Foranysystemtoprovideanoutput,e.g.,speed,temperature,voltage,etc,anerrorsignalmustexistundersteady-stateconditions.躚郯碭撇炯復朋掎德剝鴯疫驢拿ElectricalBraking碉紗蓀艋輝菔恕髖勰睬肚洼撬孢Inmanysp
4、eedcontrolsystem,e.g.,rollingmillsminewinders,etc.,theloadhastobefrequentlybroughttoastandstillandreversed.Therateatwhichthespeedreducesfollowingareducedspeeddemandisdependentonthestoredenergyandthebrakingsystemused.Asmallspeedcontrolsystem(sometimesknownasavel
5、odyne)canemploymechanicalbraking,butthisisnotfeasiblewithlargespeedcontrollerssinceitisdifficultandcostlytoremovetheheatgenerated.骶睥餼嫗帔砹掐嚷滯突迅遮樊撼Thevariousmethodsofelectricalbrakingavaiableare:億峰艾事肆嚷材休巋眠午但籜霪(1)Regenerativebraking.造瓞祛畢銚血幛氖蒲鷹匪?酮牽(2)Eddycurrentbrak
6、ing.彝烀招剪裕吻禺瓢押累貳誣忱橐(3)Dynamicbraking.黲處彰速孌穎氯禽立詭害卻憧輕(4)Reversecurrentbraking(plugging).僳謾郊凋壟奄肋猊關滁凜芒輔耒Regenerativebrakingisthebestmethod,thoughnotnecessarilythemosteconomic.Thestoredenergyintheloadisconvertedintoelectricalenergybytheworkmotor(actingtemporarilyasag
7、enerator)andisreturnedtothepowersupplysystem.Thesupplysystemthusactsasa“sink”intowhichtheunwantedenergyisdelivered.Providingthesupplysystemhasadequatecapacity,theconsequentriseinterminalvoltagewillbesmallduringtheshortperiodsofregeneration.IntheWard-Leonardmeth
8、odofspeedcontrolofDCmotors,regenerativebrakingisinherent,butthyristordriveshavetobearrangedtoinverttoregenerate.Inductionmotordrivercanregenerateiftherotorshaftisdrivenfaste
