LEAKAGE CURRENT DETECTION DEVICE FOR LEAKAGE CIRCUIT BREAKER

摘要

PROBLEM TO BE SOLVED: To provide a leakage current detection device for a leakage circuit breaker that is improved to improve a detection function of a leakage current and reliability of operational characteristics.SOLUTION: The leakage current detection device for the leakage circuit breaker is packaged in a main body case, detects a leakage current of AC and DC components circulating in a main circuit and opens a main circuit contact in the case where the leakage current exceeds a predetermined threshold value. The leakage current detection device includes: an AC zero-phase-sequence current transformer in which a secondary coil is wound around a first core surrounding a main circuit conductor; a DC flux-gate type DC current transformer in which a secondary coil is wound around a second core surrounding the main circuit; and a signal processing circuit. A shield plate 8 is interposed between a first core 4a and a second core 5a, and the first and second cores 4a and 5a are then collectively accommodated in a common shield case 9. Further, the shield case 9 is accommodated in a resin case 11 via a shield plate 10, and the resin case 11 then includes output terminals 4d and 5d for the secondary coils wound around the first and second cores and a terminal 4e for a test coil.