绕线转子异步电动机的控制线路.ppt
中间继电器的符号,复 习,2.电流继电器 反映输入量为电流的继电器叫做电流继电器。 电流继电器的线圈串联在被测电路中， 当通过线圈的电流达到预定值时，其触头动作。,复 习,（1）过电流继电器 当通过继电器的电流超过预定值时就动作的继电器称为过电流继电器。 （2）欠电流继电器 当通过继电器的电流减小到低于其整定值时就动作的继电器称为欠电流继电器。,复 习,课题八：绕线转子异步电动机的控制线路（一）,学习目标： 熟悉绕线转子异步电动机控制线路的构成和工作原理。,课题八：绕线转子异步电动机的控制线路,一、转子绕组串接电阻启动控制线路 1.转子串接三相电阻启动原理 2.按钮操作控制线路 3.时间继电器自动控制线路 4.电流继电器自动控制线路 二、转子绕组串接变阻器启动控制线路 1.频敏变阻器 2.转子绕组串接频敏变阻器启动控制线路 三、凸轮控制器控制线路,YR系列 符号,绕线转子三相异步电动机，可以通过滑环在转子绕组中串接电阻来改善电动机的机械特性，从而达到减小启动电流、增大启动转矩以及调节转速的目的。,绕线转子异步电动机控制线路,1、应用场合： 在要求启动转矩较大且有一定调速要求的场合，如：起重机、卷扬机等，常常采用三相绕线转子异步电动机拖动。 2、分类： （1）转子绕组串接电阻启动控制线路 （2）转子绕组串接频敏变阻器控制线路 （3）凸轮控制器控制线路,一、转子绕组串接电阻启动控制线路,1.转子串接三相电阻启动原理 启动时，在转子回路串入作Y形连接、分级切换的三相启动电阻器，以减小启动电流、增加启动转矩。随着电动机转速的升高，逐级减小可变电阻。启动完毕后，切除可变电阻器，转子绕组被直接短接，电动机便在额定状态下运行。,转子串接三相对称电阻器,转子串接三相不对称电阻器,2.按钮操作控制线路 特点： 工作原理简单，操作不便，工作的安全性和可靠性较差，所以生产实际中不常用。,L1L2L3,FU1,KM1,FU2,KH,SB5,QS,SB1,KM2,KM3,KM,KM1,KM3,KM2,KM1,KM3,KM2,KM,R1,R2,R3,KH,SB2,SB3,SB4,电路组成分析,KM,L1L2L3,KM1,SB5,SB1,KM2,KM3,KM,KM1,KM3,KM2,KM1,KM,KM3,KM2,KM,R1,R2,R3,SB2,SB3,SB4,合上QS 按下SB1 绕线转子串联全部电阻启动,FU1,FU2,QS,KH,KH,L1L2L3,KM1,SB5,SB1,KM2,KM3,KM,KM1,KM3,KM2,KM1,KM,KM3,KM2,KM,R1,R2,R3,SB2,SB3,SB4,按下SB2 KM1线圈得电 KM1触头闭合 绕线转子串联R2,R3启动,FU1,FU2,QS,KH,KH,L1L2L3,KM1,SB5,SB1,KM2,KM3,KM,KM1,KM3,KM2,KM1,KM,KM3,KM2,KM,R1,R2,R3,SB2,SB3,SB4,按下SB3 KM2线圈得电 KM2触头闭合 绕线转子串联R3启动,FU1,FU2,QS,KH,KH,L1L2L3,KM1,SB5,SB1,KM2,KM3,KM,KM1,KM3,KM2,KM1,KM,KM3,KM2,KM,R1,R2,R3,SB2,SB3,SB4,按下SB4 KM3线圈得电 KM3触头闭合 绕线转子切除全部电阻运行,FU1,FU2,QS,KH,KH,L1L2L3,KM1,SB5,SB1,KM2,KM3,KM,KM1,KM3,KM2,KM1,KM,KM3,KM2,KM,SB2,SB3,SB4,松开SB4 电动机继续运行,R1,R2,R3,FU1,FU2,QS,KH,KH,3.时间继电器自动控制线路 特点： 线路利用三个时间继电器和三个接触器的相互 配合来依次自动切除转子绕组中的三级电阻,L1L2L3,FU1,KM1,FU2,KH,SB2,QS,SB1,KM2,KM3,KM,KM,KT3,KM3,KM2,KM1,KM3,KM2,KM1,KM,R1,KT1,KT2,KT3,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,KH,电路组成分析,L1L2L3,SB2,SB1,KM3,KM,KM,KT3,KM2,KM1,KM3,KM2,KM1,R1,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,合上QS 按下SB1 KM线圈得电,KM1,KM2,KM3,KM,KT1,KT2,KT3,FU1,FU2,KH,QS,KH,L1L2L3,M 3,SB2,SB1,KM3,KM,KM,KT3,KM2,KM1,KM3,KM2,KM1,R1,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,KM触头闭合 绕线转子串联全部电阻启动 KT1线圈得电,KM1,KM2,KM3,KM,KT1,KT2,KT3,FU1,FU2,KH,QS,KH,L1L2L3,M 3,SB2,SB1,KM3,KM,KM,KT3,KM2,KM1,KM3,KM2,KM1,R1,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,KT1延时闭合触头闭合 KM1线圈得电,KM1,KM2,KM3,KM,KT1,KT2,KT3,FU1,FU2,KH,QS,KH,L1L2L3,M 3,SB2,SB1,KM3,KM,KM,KT3,KM2,KM1,KM3,KM2,KM1,R1,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,KM1触头闭合 绕线转子串联R2,R3启动 KT2线圈得电,KM1,KM2,KM3,KM,KT1,KT2,KT3,FU1,FU2,KH,QS,KH,L1L2L3,M 3,SB2,SB1,KM3,KM,KM,KT3,KM2,KM1,KM3,KM2,KM1,R1,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,KT2延时闭合触头闭合 KM2线圈得电,KM1,KM2,KM3,KM,KT1,KT2,KT3,FU1,FU2,KH,QS,KH,L1L2L3,M 3,SB2,SB1,KM3,KM,KM,KT3,KM2,KM1,KM3,KM2,KM1,R1,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,KM2触头闭合 绕线转子串联R3启动 KT3线圈得电,KM1,KM2,KM3,KM,KT1,KT2,KT3,FU1,FU2,KH,QS,KH,L1L2L3,M 3,SB2,SB1,KM3,KM,KM,KT3,KM2,KM1,KM3,KM2,KM1,R1,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,KT3延时闭合触头闭合 KM3线圈得电,KM1,KM2,KM3,KM,KT1,KT2,KT3,FU1,FU2,KH,QS,KH,L1L2L3,M 3,SB2,SB1,KM3,KM,KM,KT3,KM2,KM1,KM3,KM2,KM1,R1,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,KM3触头闭合 绕线转子切除全部电阻运行,KM1,KM2,KM3,KM,KT1,KT2,KT3,FU1,FU2,KH,QS,KH,L1L2L3,M 3,SB2,SB1,KM3,KM,KM,KT3,KM2,KM1,KM3,KM2,KM1,R1,R2,R3,KM,KM1,KM2,KM3,KM3,KT1,KT2,KM3动断触头断开 KT1线圈失电 KT1触头断开 KM1线圈失电 KM1触头动作 KT2线圈失电 KT2触头动作 KM2线圈失电 KM2触头动作 KT3线圈失电 KT3触头断开 电动机继续运转,KM1,KM2,KM3,KM,KT1,KT2,KT3,FU1,FU2,KH,QS,KH,思考,？将三个触器的辅助常闭触头与启动按钮串接，这样做的目的是什么？,思考答案,目的： 如果三个接触器中的任何一个因触头熔焊或机械故障而不能正常释放时，即使按下启动按钮，控制电路也不会得电，电动机就不会接通电源启动运行。,4.电流继电器自动控制电路 绕线转子异步电动机刚启动时转子电流较大，随着电动机转速的增大，转子电流逐渐减小，根据这一特性，可以利用电流继电器自动控制接触器来逐级切除转子回路的电阻。,L1L2L3,FU1,3,FU2,KH,SB2,QS,SB1,KM,KM,KA1,KM2,KM,R2,R1,KA2,KH,KA1,KA,KM3,KA3,R3,KA3,KM1,KM1,KM2,KM3,KA2,KA,KM,KM1,KM2,KM3,电路组成分析,L1L2L3,FU1,3,SB2,SB1,KM,KM,KA1,KM2,KM,R2,R1,KA2,KA1,KA,KM3,KA3,R3,KA3,KM1,KM1,KM2,KM3,KA2,KA,KM,KM1,KM2,KM3,合上QS 按下SB1 KM线圈得电,FU2,KH,QS,KH,L1L2L3,FU1,3,SB2,SB1,KM,KM,KA1,KM2,KM,R2,R1,KA2,KA1,KA,KM3,KA3,R3,KA3,KM1,KM1,KM2,KM3,KA2,KA,KM,KM1,KM2,KM3,KM触头闭合 绕线转子串联全部电阻启动 K线圈得电,FU2,KH,QS,KH,L1L2L3,FU1,3,SB2,SB1,KM,KM,KA1,KM2,KM,R2,R1,KA2,KA1,KA,KM3,KA3,R3,KA3,KM1,KM1,KM2,KM3,KA2,KA,KM,KM1,KM2,KM3,KA常开触头闭合,为KM1,KM2,KM3得电作准备 因启动电流大KA1,KA2,KA3的动断触头断开,继续串联全部电阻启动,FU2,KH,QS,KH,L1L2L3,FU1,3,SB2,SB1,KM,KM,KA1,KM2,KM,R2,R1,KA2,KA1,KA,KM3,KA3,R3,KA3,KM1,KM1,KM2,KM3,KA2,KA,KM,KM1,KM2,KM3,因速度加快，电流减小， KA1欠电流,动断触头闭合，,KM1线圈得电KM1触头闭合,切除第一组电阻R1 串联R2,R3继续启动,FU2,KH,QS,KH,L1L2L3,FU1,3,SB2,SB1,KM,KM,KA1,KM2,KM,R2,R1,KA2,KA1,KA,KM3,KA3,R3,KA3,KM1,KM1,KM2,KM3,KA2,KA,KM,KM1,KM2,KM3,因速度再加快电流继续减小 ， KA2欠电流, 动断触头闭合KM2线圈得电KM2触头闭合，切除第二组电阻R2 串联R3继续启动,FU2,KH,QS,KH,L1L2L3,FU1,3,SB2,SB1,KM,KM,KA1,KM2,KM,R2,R1,KA2,KA1,KA,KM3,KA3,R3,KA3,KM1,KM1,KM2,KM3,KA2,KA,KM,KM1,KM2,KM3,因速度再加快电流继续减小 KA3欠电流, 动断触头闭合KM3线圈得电KM3触头闭合切除全部电阻, 电动机启动完毕，全速运行,FU2,KH,QS,KH,思考,？中间继电器的作用？,思考答案：,中间继电器的作用是保证电动机在转子电路中接入全部电阻的情况下开始启动。因为电动机开始启动时，转子电流从零增大到最大值需要一定的时间，这样有可能电流继电器KA1、KA2、KA3还未动作，接触器KM1、KM2、KM3就已经吸合而把三个电阻R1、R2、R3短接，造成电动机的直接启动。 接入中间继电器后，启动时由KA的常开触头断开KM1、KM2、KM3线圈的通电回路，保证了启动时转子回路串入全部的电阻。,本节小结,转子绕组串接电阻启动控制线路 1.转子串接三相电阻启动原理 2.按钮操作控制线路 3.时间继电器自动控制线路 4.电流继电器自动控制线路,
