Vacuum Distribution Device for mine explosion-proof permanent magnet high-voltage vacuum distribution device PBG-10 (6,3.3) ... neutral line directly grounded to realize no-spot and remote control on 3-phase squirrel-cage asynchronous motors, his device divided ... into 4 kinds of a,b,c,d, to meet with different requirements of consumer, inter-connection, feeding, inter-coupled and direct control.