JPS54148254A - Controller for circuit breaker - Google Patents

Abstract

PURPOSE: To quickly open a circuit breaker with regard to both a forward current and a recerse current, by amplifying the current of a magnetism-electricity converter provided in a conductor of a main circuit and by discharging a commutation capacitor by forward and recerse pulse generators to actuate a trip unit when the amplified current has reached a setpoint.

CONSTITUTION: When the output of the magnetism-electricity converter 2 such as a Hall element placed in a gap 1a of an iron core 16 surrounding the main circuit conductor 1 of the circuit breaker is amplified to the setpoint by an amplifier 3, a first generator 7 or a second generator 8 produces a gate pulse depending on the direction of the main current to turn on a thyristor 11 through an OR circuit consisting of diodes 9, 10 to start the trip unit. Thyristors 12, 13 or thyristors 14, 15 are triggered depending on the direction of the main current, with a time difference from the thyristor 11, which is proviously set in the pulse generators 7, 8, so that the current is made zero by the commutation capacitor at the time of contact opening of the circuit breaker. The circuit breaker is thus quickly opened with regard to both the directions of the current.

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