OVERVOLTAGE PROTECTIVE RELAY Russian patent published in 2002 - IPC

FIELD: electrical engineering; protective relays responding to voltage rise in electrical installation circuit. SUBSTANCE: proposed relay has its circuits free from lagging components such as electrolytic capacitors whose parameters greatly depend on ambient temperature as well as on shelf life and operating time. Its measuring and control circuits have no common components. Newly introduced in relay are following parts: full-wave rectifier whose input is connected to sensor output and its negative pole is connected to that of power supply; measuring circuit of two connected in series resistors connected in parallel with output of full-wave rectifier their midpoint being connected to noninverting input of operational amplifier; relay setting circuit incorporating voltage limiter built around voltage regulator diode and resistor connected to its cathode and to positive pole of full-wave rectifier; anode of voltage regulator diode is connected to negative pole of power supply; voltage divider connected in parallel with voltage regulator diode and built up of two series-connected resistors whose midpoint is connected to inverting input of operational amplifier; rectifier output is connected to input of amplifier output stage. EFFECT: enhanced speed of response and operating reliability; facilitated adjustment. 1 dwg