压缩机电机起动理论PPT课件

MotorStartTheory,电机起动原理,T-2005-11001MST,LowSlipvFullSlip低滑移与满滑移,0,50,100,150,200,250,300,100,90,80,70,60,50,40,30,20,10,0,SLIP(%),FULLLOADTORQUE(%),0,100,200,300,400,500,600,700,CURRENT(%),Amotorsstartperformancecharacteristicssetthelimitsofwhatcanbeachievedwitheitherafullvoltageorreducedvoltagestarter.电机起动性能规定使用全电压起动器或降压起动器能达到的极限值。Itisespeciallyimportanttoconsidermotorstartcharacteristicswhenseekingto:-MinimisestartcurrentMaximisestarttorque当尝试以下方式时考虑电机起动特性尤其重要：-将起动电流降至最小-将起动扭矩增至最大,MotorPerformance电机性能,Rotordesignaffectsstartingperformance.转子的设计影响起动性能。Statordesignaffectsfullspeedperformance.定子的设计影响全速性能。Theshape,positionandmaterialoftherotorbarsaffectthecurrentdrawnandtorqueproducedduringmotorstarting.转子杆的形状、位置和材料影响引入电流和电机起动时产生的扭矩。,MotorPerformance电机性能,Amotorsstartperformancecanbeidentifiedbyexaminingthemotordatasheet.电机起动性能可通过检查电机数据表得到确认。Thetabledetailsselectedperformancedataforarangeof110kWmotors.数据表详述了110kW电机系列选用的性能数据。,TypicalMotorData典型电机数据,MotorSpeedFLCLRCLRT%FLTorque(rpm)(amps)(%FLC)(%FLT)Efncy3xFLCA14701916002639365.8B147518460019093.547.5C14751915701509241.6D148018766019094.539.2E14701855501209236F14701916701509330.1G14801907802009429.6H147518285022093.527.4I14801906701209424,SampleOfTypical110kWMotors,MaximummotorstartcurrentunderfullvoltagestartconditionsisdefinedbythemotorsLockedRotorCurrent(LRC).全电压起动条件下最大电机起动电流是由电机锁定转子电流（LRC）确定的。LRClevelsvaryconsiderablybetweenmotors.LRC等级在电机间有显著变化。Intheexample,MotorHwilldraw55%morecurrentatstartthanMotorE.在实例中，电机H引入的起动电流比电机E多55%。,StartCurrent起动电流,MotorSpeedFLCLRCLRT%FLTorque(rpm)(amps)(%FLC)(%FLT)Efncy3xFLCA14701916002639365.8B147518460019093.547.5C14751915701509241.6D148018766019094.539.2E14701855501209236F14701916701509330.1G14801907802009429.6H147518285022093.527.4I14801906701209424,LRCrangesfrom550%to850%,SampleOfTypical110kWMotors,MotorstarttorqueperformanceisindicatedbythemotorsLockedRotorTorque(LRT)figure.电机起动扭矩性能是由电机的锁定转子扭矩（LRT）图表示的。LRTlevelsvaryconsiderablybetweenmotors.LRT等级在各个电机间有显著变化。Intheexample,MotorAproducestwiceasmuchtorqueduringstartasMotorI.在实例中，电机A起动时产生的扭矩是电机I的两倍。,StartTorque起动扭矩,MotorSpeedFLCLRCLRT%FLTorque(rpm)(amps)(%FLC)(%FLT)Efncy3xFLCA14701916002639365.8B147518460019093.547.5C14751915701509241.6D148018766019094.539.2E14701855501209236F14701916701509330.1G14801907802009429.6H147518285022093.527.4I14801906701209424,LRTrangesfrom120%to263%,SampleOfTypical110kWMotors,LRC2disconnectfromthereducedvoltage(opencircuit);3connecttothefullvoltage.Opentransitionstartingcausesseverecurrent&torquetransientsthatcanbemoredetrimentaltothesupplyandthemechanicalequipmentthanfullvoltagestarting.Whenthemotorisspinningandthendisconnectedfromthesupply,itactsasagenerator.Outputvoltagecanbethesameamplitudeasthesupply.Atthetimeofreclosetherecanstillbesignificantvoltagepresentatthemotorterminals.Voltagegeneratedbythemotorattheinstantofreclosemaybeequaltothesupplyvoltagebutexactlyoutofphase.Thisequatestoreclosingwithtwicethesupplyvoltageonthemotor.Theresultisacurrentoftwicelockedrotorcurrentandatorquetransientoffourtimeslockedrotortorque.,开路瞬变转换,当起动器以转换顺序通过开路段时发生。1连接降压；2与降压（开路）断开；3连接满电压。开路瞬变起动造成严重的电流和扭矩瞬变，这对电源和机械设备可能比满电压起动更加有害。当电机旋转、然后与电源断开时，起到发电机的作用。输出电压可与电源振幅相同。再合闸时，仍可有明显的电压出现在电机终端。再合闸瞬间电机产生的电压可与电源电压相等但正好失相。这等于再合闸电机上有两倍的电源电压。这一结果是两倍锁定转子电流的电流和四倍锁定转子扭矩的扭矩瞬变。,SoftStarter软起动器,SoftStarterscontrolthevoltageappliedtothemotorbytheuseofsolidstateACswitches(SCRs)inserieswiththesupplytothemotor.软起动器通过与电机电源串接的固态AC开关（ACR）控制电机电压。,-Minimumpossiblestartcurrent-Nocurrentsteps-NotorquestepsGoodstarttorquecharacteristics起动电流可达最低没有电流步进没有扭矩步进良好的起动扭矩特性,SoftStarter软起动器,0,50,100,150,200,250,300,100,90,80,70,60,50,40,30,20,10,0,SLIP(%),FULLLOADTORQUE(%),0,100,200,300,400,500,600,700,CURRENT(%),Motorcharacteristicssetthelimitsofwhatcanbeachievedwithasoftstarter.电机特性决定软起动器所能达到的极限。Payspecialattentiontomotorcharacteristicswhen:在以下情况下要特别注意电机特性:itisimportanttominimisestartcurrent-将起动电流降至最低是十分重要的-itisimportanttomaximisestarttorque-将起动扭矩增至最大是十分重要的-dealingwithlargemotors(200kW+)-涉及大型电机（200kW+）,Summary总结,Softstartistechnicallythebestreducedvolta