... control equipment include :rectification transformer,alternating contactor,rectification two-electrode valve,direct current contactor,time relay,discharge resistance,RK-SWB and ... When we turn on the lifing switch,direct current contactor KM1,KM3 closed,transformer secondary winding and supply alternating ... ,about 1~2 second later,(adjust KT), dropping contactor is power off,then all the iron billets or ...