| 摘要 |
PROBLEM TO BE SOLVED: To provide a ground fault circuit interrupter which prevents change of leak detecting sensitivity due to a noise current in a secondary winding caused by a stray capacitance between a test winding and the secondary winding. SOLUTION: The ground fault circuit interrupter 1 comprises a zero-phase current transformer 4 having the secondary winding 5 to lead out a zero-phase- sequence component of the current in main electric paths (R-U), (S-V), (T-W) and the test winding 11 to test-operate this interrupter 1, a leak detector 6 which opens an interrupting part 2 by energizing a trip coil 7 when a zero-phase current in the secondary winding 5 exceeds the predetermined one, and a rectifier circuit 10 which generates direct current for the leak detecting part 6 by rectifying the voltage of the main electric paths with one of direct current supply paths thereof, a ground line connected to a signal ground SG of the leak detecting part 6. When a test contact 9 is open and the interrupter 1 monitors leak, and potentials of the test winding 11 and the secondary winding 5 are the same because of the connection of one end of the test winding 11 to the ground line resulting in no noise current due to stray capacitance. COPYRIGHT: (C)2003,JPO
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