Timing circuit for electronic undervoltage detecting device and latch

Abstract From the Canadian patent

A timing device utilizing a transistor and silicon controlled rectifier to provide a momentary relatively high voltage for the solenoid coil of a tripping device which is part of an undervoltage detecting and tripping circuit to thus nergize the coil to allow closing of a circuit breaker which is controlled by the undervoltage device when low voltage which originally caused the circuit breaker to trip is no longer present on the line to be protected by the circuit breaker. The relatively high voltage changes to a normal value shortly thereafter.