SWITCH Russian patent published in 2004 - IPC

FIELD: electrical engineering; load disconnection from power supply in case of circuit troubles. SUBSTANCE: switch incorporates three-phase power supply and one load connected to power supply via three energized power lines (R-R', S-S', and T-T'). Switch has flip-flop circuit incorporating selector switch connected in series with lines running to power supply end of one transformer that has at least three balancing primary windings series-connected with respective power lines and with secondary winding; one voltage comparator connected to secondary winding designed to compare one value of transformer inductance voltage with one value of reference voltage and to send state change signal to flip-flop circuit on occurrence of current leakage for disconnecting selector switch. Circuit line has voltage sensor-comparator assembly for determining and comparing two phase-to-phase voltages beyond transformer and to simulate fault leakage of determining transformer and voltage comparator on occurrence of unbalance voltage failure so as to provide for state change signal. EFFECT: improved design of switch. 10 cl, 2 dwg