GEAR FOR PROTECTIVE DISCONNECTION OF ELECTRIC INSTALLATION FROM A C NETWORK WITH THREE PHASE AND ONE NEUTRAL WIRES Russian patent published in 1994 - IPC

FIELD: electrical engineering. SUBSTANCE: gear relates to technical means of protection of attending personnel of electric installations connected to four-wire A.C. network against injuries with electric current. Gear includes magnetic starter with buttons START and STOP 1, current transformer of zero sequence, voltage amplifier, relay, asymmetry meter composed of unbalancing and balancing units with button STOP 2. Gear is supplemented with second asymmetry meter, current transformer of zero sequence and voltage amplifier. EFFECT: increased reliability and level of electric safety. 1 dwg