THE SINGLE-PHASE CIRCUIT BRAKER BUILT IN TRIP FUNCTION THOUGH NEUTRAL PHASE FAILS

摘要

A single-phase two-wire circuit breaker is provided to open a contact of a circuit breaker by continuously supplying a control power to an overvoltage and electric leakage detecting part in an open-phase of a neutral wire. An open-phase detecting part(100) of a neutral wire senses an open-phase of the neutral wire, and generates a control signal. The open-phase detecting part of the neutral wire includes a thyristor(150) and a photocoupler. The thyristor is turned on in response to the control signal. The thyristor supplies a control power to an inner circuit of a circuit breaker by connecting a phase wire to a ground wire until a contact of the circuit breaker is opened. The photocoupler generates a trigger pulse of a fixed cycle as a detecting signal. A control part(300) determines a temporary open-phase of the neutral wire by counting a frequency of the detecting signal received from the open-phase detecting part of the neutral wire.