DEVICE FOR CONTROLLING THREE-PHASE SWITCH BUILT AROUND TRIACS

FIELD: phase-failure protection of three-phase loads. ^ SUBSTANCE: proposed control device for three-phase switch built around triacs connected to supply mains phase leads has diode group assembled of two diodes integrated by cathodes and thyristor, all connected through anodes to output terminals of switch, thyristor gate electrode being connected to control unit built around optocoupler whose photothyristor is connected through first limiting resistor to thyristor anode and light-emitting diode anode is connected through anode to cathodes of diode group and its cathode, to neutral bus through variable resistor and second limiting resistor; first and second control buttons; three phase optocouplers whose photothyristors are connected through respective limiting resistors to bridge amplifier output and input is designed for connecting to control junction of respective triac; light-emitting diodes of phase optocouplers are cumulatively interconnected in series, shorted out by second control button, and connected through anode of first light-emitting diode to cathodes of diode group and to first lead of first trigger control button connected by its second lead to cathode of diode whose anode is connected to one of supply mains phase leads, and cathode of third light-emitting diode is connected through load resistor to neutral bus. ^ EFFECT: reduced heat loss, enhanced reliability of device. ^ 1 cl, 1 dwg