| 摘要 |
PROBLEM TO BE SOLVED: To provide a test circuit of an earth leakage breaker, by which a test switch can be miniaturized, and a wrong operation can be prevented. SOLUTION: The test circuit 1 of an earth leakage breaker is so constructed that two test resistances 3a, 3b having the same resistance value are serially connected to a power source 2, a test switch 4 is connected between the two test resistances 3a, 3b, and a pseudo leakage current flowing through the circuit by turning the test switch 4 on is detected by a zero phase current transformer, and voltage applied between contacts 4a of the test switch 4 is preset to a half of the source voltage. COPYRIGHT: (C)2004,JPO
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