图1所示空载停电装置,其工作原理如下:当 K 合上时,电流经 DZ_2、交流接触器 CJ而通路。这时,CJ_1、CJ_3闭合,CJ_2开打,在 L_2上感应出60～70伏左右空载电压,并到单晶体营 BT 的峰点电压。e、b_1导通,中间继电器 DZ 工作,DZ_1、DZ_3闭合,DZ_2打开;CJ 断电,于是CJ_1、CJ_3打开,CJ_2闭合,电源切断。这时,电容 C_3对 R_4进行放 Figure 1 shows the no-load power failure device, its working principle is as follows: When K closes, the current through the DZ_2, AC contactor CJ and access. At this moment, CJ_1 and CJ_3 are closed, CJ_2 is opened and a no-load voltage of about 60~70 volts is induced on L_2, and the peak voltage of single-crystal BT is reached. e, b_1 turn on, the middle relay DZ work, DZ_1, DZ_3 closed, DZ_2 open; CJ power, so CJ_1, CJ_3 open, CJ_2 closed, the power cut off. At this time, the capacitor C_3 R_4 put