MOLDED-CASE CIRCUIT BREAKER WITH LEAKAGE ALARM FUNCTION

摘要

PROBLEM TO BE SOLVED: To provide a molded-case circuit breaker with leakage alarm function which can incorporate an open-phase protection function for neutral conductors without changing printed boards of the molded-case circuit breaker, achieve easier stock control, provide dimensional allowance in the layout of parts and patterns comprising the printed board, carry out parts replacement with lower cost, and perform independent quality check of the open-phase protection function for neutral conductors.;SOLUTION: An open-phase protection unit 8 has a printed board 10 equipped with an abnormal voltage detection circuit for detecting an abnormal voltage due to open phase of a neutral conductor, a release apparatus comprising a plunger 13 and a trip coil 11 driven by the output from the abnormal voltage detection circuit, an open-phase indicating button 15 for indicating the state of open phase, an open-phase test circuit comprising a test button 19, a switch 18 and a test resistance for checking the operation of the open-phase protection function for neutral conductors. The open-phase protection unit 8 is installed within the body of the circuit breaker 7.;COPYRIGHT: (C)2002,JPO