| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a test circuit of a ground fault interrupter in which the ripple rate of an imitation leakage current flowed in a test circuit is improved, by skillfully utilizing a surge suppressor connected to an input side power supply line of a three-phase full-wave rectifier circuit as a measure against interline surge of the power supply circuit, and which is improved so that leakage test function operates appropriately, even when any on of the three phases has failed. Ž<P>SOLUTION: The ground fault interrupter includes a zero-phase current transformer 4 which uses each phase of the three-phase electric path as a primary conductor, a leakage detection circuit 5, which detects the occurrence of fault of the electric path from a secondary output of the zero-phase current transformer; a three-phase full-wave rectifier circuit 10 which supplies power to a power supply circuit 9 of a leakage detection circuit from the three-phase electric path; and a rest circuit 11. Three pieces of surge suppressors 14 are connected, in a star connection among each phase lines of the input side power supply line of the three-phase full wave rectifier circuit 10; the test circuit 11 is connected between a center tap O of the star connection and the positive-side output line P of the three-phase full wave rectifier circuit 10; and by utilizing the limiting voltage of the surge suppressor 14, the test current with high ripple facttoris obtained. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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