| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a ground-fault circuit interrupter which lowers the voltage applied across the contacts of a test switch and can reduce the isolation resistance between a test coil and the secondary coil of a zero-phase current transformer. <P>SOLUTION: The ground-fault circuit interrupter includes: the zero-phase current transformer inserted in an ac current path; a leakage detecting circuit which generates an output signal, when a leak current flowing through the zero phase current transformer exceeds a given level; a tripping circuit which trips a breaker unit inserted in the ac current path, in response to the output signal from the leak detecting circuit; a rectifying circuit which rectifies the voltage of the ac current path, to supply the rectified voltage to the leak detecting circuit; and a test circuit which supplies a flow of pseudo-leakage current to a test coil which are coiled around the zero-phase current transformer. The test circuit is made up of a serial connection constituted of the test coils, test switches, limiting resistances, and optical insulating means, the serial connection which is connected to the output end of the rectifying circuit. <P>COPYRIGHT: (C)2009,JPO&INPIT |
