课题六三相异步电动机的制动控制线路所谓制动,就是给电动机一个与转动方向相反的转矩使它迅速停转(或限制其转速)。制动的方法一般有两类:机械制动和电力制动。一、机械制动当电动机的定子绕组断电后,利用机械装置使电动机立即停转。机械制动电磁抱闸制动器MZD1系列交流单相制动电磁铁TJ2系列闸瓦制动器1-线圈2-衔铁3-铁心4-弹簧5-闸轮6-杠杆7-闸瓦8-轴电磁抱闸制动器结构示意图电磁抱闸制动器工作原理示意图1-弹簧2-衔铁3-线圈4-铁心5-闸轮6-闸瓦7-杠杆电源TJ2系列闸瓦制动器与MZD1系列交流制动电磁铁的配用表制动器型号制动力矩(N·m)闸瓦退距(mm)正常/最大调整杆行程(mm)开始/最大电磁铁型号电磁铁转矩(N·m)通电持续率为25%或40%通电持续率为100%通电持续率为25%或40%通电持续率为100%TJ2-100TJ2-200/100TJ2-200TJ2-300/200TJ2-30020401602405001020801202000.4/0.60.4/0.60.5/0.80.5/0.80.7/12/32/32.5/3.82.5/3.83/4.4MZD1-100MZD1-200MZD1-200MZD1-200MZD1-3005.55.5404010033202040例:MZD1-100MZD1-200电磁铁和制动器的型号电磁铁和制动器的型号例:TJ2-100TJ2-200/100电磁抱闸断电制动控制线路L1L2L3FU1FU2KMKHSB2SB1KMYBQSKMKHM3~电磁抱闸断电制动控制线路L1L2L3FU1FU2KMSB2SB1KMYBQSKM合上电源开关QSKHKHM3~电磁抱闸断电制动控制线路L1L2L3FU1FU2KMSB2SB1KMYBQSKM按下SB2KM线圈得电KHKHM3~电磁抱闸断电制动控制线路L1L2L3FU1FU2KMSB2SB1KMYBQSKMKM1自锁触头闭合,自锁,松开SB2电磁抱闸线圈YB得电,使抱闸的闸瓦与闸轮分开KM1主触头闭合,电动机起动运行KHKHM3~电磁抱闸断电制动控制线路L1L2L3FU1FU2KMSB2SB1KMYBQSKM停:按SB1,接触器KM失电释放电磁抱闸线圈YB也失电,在弹簧的作用下,闸瓦与闸轮紧紧抱住KHKHM3~电磁抱闸通电制动控制线路L1L2L3FU1FU2KM1KHSB1SB2KM1YBQSKM1KHM3~KM2KM2KM1电路组成分析电磁抱闸通电制动控制线路L1L2L3FU1KM1SB1SB2KM1QSKM1KM2KM1合上电源开关QSKM2KHKHM3~FU2YBKM2电磁抱闸通电制动控制线路L1L2L3FU1KM1SB1SB2KM1QSKM1KM2KM1按下SB1KM1线圈得电KM2KHKHM3~FU2YBKM2电磁抱闸通电制动控制线路L1L2L3FU1KM1SB1SB2KM1QSKM1KM2KM1KM1自锁触头闭合,自锁,松开SB1KM1联锁触头断开,KM1主触头闭合电动机起动运行电磁抱闸线圈YB不得电KM2KHKHM3~YBKM2FU2电磁抱闸通电制动控制线路L1L2L3FU1KM1SB1SB2KM1QSKM1KM2KM1KM2停:按下SB2KM1线圈失电释放KM2线圈得电,KM2主触头闭合电磁抱闸线圈YB得电,使闸瓦与闸轮紧紧抱住KHKHM3~YBFU2二、电力制动电动机产生一个和电动机实际旋转方向相反的电磁转矩,使电动机迅速停转。(一)反接制动1.反接制动原理在停车时,把电动机反接,则其定子旋转磁场便反向旋转,在转子上产生的电磁转矩亦随之变为反向,成为制动转矩。反接制动单向启动反接制动控制M3~L1L2L3FU1FU2KM1KM2KHSB1KM1SB2KM2KM1KM2KHQSRKM1nKSKM2KS单向启动反接制动控制L1L2L3FU1FU2KM2SB1KM1SB2QSRKM1nKSKM2KS合上电源开关QSM3~KM1KHKM2KHKM1KM2单向启动反接制动控制L1L2L3FU1FU2KM2SB1KM1SB2KM1KM2QSRKM1nKSKM2KS按下SB1KM1线圈得电M3~KM1KHKM2KH单向启动反接制动控制L1L2L3FU1FU2KM2SB1KM1SB2KM1KM2QSRKM1KSKM2KSnKM1自锁触头闭合,自锁,松开SB1KM1主触头闭合,电动机起动,运行在转速高到一定值时,KS闭合M3~KM1KHKM2KH单向启动反接制动控制L1L2L3FU1FU2KM2SB1KM1SB2KM1KM2QSRKM1KM2KSn停:按下SB2KM1失电释放KM2线圈得电,KM2主触头闭合,电动机串联电阻反接,反接制动KM2自锁触头闭合M3~KM1KHKM2KHKS单向启动反接制动控制L1L2L3FU1FU2KM2SB1KM1SB2KM1KM2QSRKM1KM2KSn停:松开SB2继续反接制动M3~KM1KHKM2KHKS单向启动反接制动控制L1L2L3FU1FU2KM2SB1KM1SB2KM1KM2QSRnKM2KS当转速降低到一定值时,KS断开KM2线圈失电,各触头复位M3~KM1KHKM2KHKM1KS(二)能耗制动电动机切断交流电源后,立即在定子线组的任意两相中通入直流电,利用转子感应电流受静止磁场的作用以达到制动目的。M3~L1L2L3KM1KHSB1KM1SB2KM2KM1KM2KHKM1KTKM2VUWQSFU1FU2KTKT单向启动能耗制动自动控制线路KM2电路组成分析定子绕组直流电通路KM2VL1L2L3KM1SB1KM1SB2KM2KM1KM2KM1KTKM2QSFU1FU2KTKTKM2合上电源开关QS按下SB1KM1线圈得电单向启动能耗制动自动控制线路KM2VM3~KHKHVUWL1L2L3KM1SB1KM1SB2KM2KM1KM2KM1KTKM2QSFU1FU2KTKTKM2KM1自锁触头闭合KM1主触头闭合KM1联锁触头分断单向启动能耗制动自动控制线路KM2VM3~KHKHVUWL1L2L3KM1SB1KM1SB2KM2KM1KM2KM1KTKM2KM2VQSFU1FU2KTKTKM2按下SB2KM1线圈失电KM1自锁触头分断KM1主触头分断KM1联锁触头闭合KM2线圈得电KT线圈得电单向启动能耗制动自动控制线路M3~KHKHVUWL1L2L3KM1SB1KM1SB2KM2KM1KM2KM1KTKM2KM2QSFU1FU2KTKTKM2KM2自锁触头闭合KM2主触头分断闭合电动机半波能耗制动KM2联锁触头分断KT瞬时闭合触头闭合松开SB2单向启动能耗制动自动控制线路VM3~KHKHVUWL1L2L3KM1SB1KM1SB2KM2KM1KM2KM1KTKM2KM2VQSFU1FU2KTKTKM2KT延时断开触头延时分断KM2线圈失电KT线圈失电各触头复位单向启动能耗制动自动控制线路M3~KHKHVUWFU2KHSB1KM1SB2KM1KM2KTKTKTKM2KM2KM1M3~L1L2L3FU1KM1QSFU3VCTCKHRKM2VUW3KM2有变压器桥式整流能耗制动控制线路电路组成分析FU2SB1KM1SB2KM1KM2KTKTKTKM2KM2KM1L1L2L3FU1KM1QSFU3VCTCRKM2VUW3KM2有变压器桥式整流能耗制动控制线路合上电源开关QS按下SB1KM1线圈得电KHM3~KHFU2SB1KM1SB2KM1KM2KTKTKTKM2KM2KM1L1L2L3FU1KM1QSFU3VCTCRKM2VUW3KM2有变压器桥式整流能耗制动控制线路KM1自锁触头闭合KM1主触头闭合KM1联锁触头分断松开SB1KHM3~KHFU2SB1KM1SB2KM1KM2KTKTKTKM2KM2KM1L1L2L3FU1KM1QSFU3VCTCRKM2VUW3KM2有变压器桥式整流能耗制动控制线路按下SB1KM1线圈失电KM1自锁触头分断KM1主触头分断KM1联锁触头闭合KM2线圈得电KT线圈得电KHM3~KHFU2SB1KM1SB2KM1KM2KTKTKTKM2KM2KM1L1L2L3FU1KM1QSFU3VCTCRKM2VUW3KM2有变压器桥式整流能耗制动控制线路KM2自锁触头闭合KM2主触头分断闭合电动机半波能耗制动KM2联锁触头分断KT瞬时闭合触头闭合松开SB1KHM3~KHFU2SB1KM1SB2KM1KM2KTKTKTKM2KM2KM1L1L2L3FU1KM1QSFU3VCTCRKM2VUW3KM2有变压器桥式整流能耗制动控制线路KT延时断开触头延时分断KM2线圈失电KT线圈失电各触头复位KHM3~KH(三)电容制动当电动机切断交流电源后,立即在电动机定子绕组的出线端接入电容器来迫使电动机迅速停转的方法叫电容制动。电容制动原理当旋转着的电动机断开交流电源时,转子内仍有剩磁。随着转子的惯性转动,形成一个随转子转动的旋转磁场。该磁场切割定子绕组产生感生电动势,并通过电容器回路形成感生电流,这个电流产生的磁场与转子绕组中的感生电流相互作用,产生一个与旋转方向相反的制动力矩,使电动机受制动迅速停转。电容制动M3~L1L2L3FU1FU2KM1KM2KHSB1SB2KM1KM1KM1KM2KHUVWQSRKM1=电路组成分析KTKTKM2合上电源开关QS按下SB1KM1线圈得电电容制动L1L2L3FU1FU2KM1KM2SB1SB2KM1KM1KM1KM2UVWQSRKM1=KTKTKM2M3~KHKH电容制动L1L2L3FU1FU2KM1KM2SB1SB2KM1KM1KM1KM2UVWQSRKM1=KTKTKM2KM1自锁触头闭合KM1主触头闭合KM1联锁触头分断KM1辅助触头闭合KT线圈得电KT瞬时闭合延时断开触头闭合松开SB1M3~KHKH电容制动L1L2L3FU1FU2KM1KM2SB1SB2KM1KM1KM1KM2UVWQSRKM1=按下SB2KM1线圈失电KM1联锁触头闭合KM2线圈得电KM2主触头闭合KM2联锁触头分断电容制动开始KTKTKM2M3~KHKH电容制动L1L2L3FU1FU2KM1KM2SB1SB2KM1KM1KM1KM2UVWQSRKM1=KT瞬时闭合延时断开触头延时分断KM2线圈失电各触头复位电容制动结束KTKTKM2M3~KHKH(四)再生发电制动当起重机在高处开始下放重物时,电动机转速n小于同步转速n1,这时电动机处于电动运行状态,转子相对于旋转磁场切割磁感线的运动方向发生了改变,其转子电流和电磁转矩的方向都与电动运行时相反。再生发电制动原理