Earth leakage detection apparatus

Abstract

The invention provides a test circuit of a leakage detection device, which can not be induced by usual mode noise in a test coil of a zero phase converter and can resist the induction radiating electromagnetic wave noise for grounding wires of the leakage detection device so that the leakage detection sensitivity is stable. In the test circuit supplying test current for the test coil (11) of the zero phase converter (4) of the leakage detection device (3), one end of the test coil (11) of the zero phase converter (4) is connected with one alternating current input end of a rectification circuit (10) by the contact point (8A) of a test switch (8), and the terminal of the test coil not connected with the test switch is connected with another alternating current input end of the rectification circuit (10) by a diode (D) with the polarity to be anode facing to the end of the test coil.

Description

technical field [0001] The present invention relates to a leakage detection device used in a leakage circuit breaker, etc., which detects the occurrence of leakage caused by a ground wire in a circuit and disconnects the circuit, and protects a load and a circuit in a leakage accident. Background technique [0002] The leakage detection device is provided with a test circuit for checking whether it operates normally. image 3 In the earth leakage circuit breaker, the circuit structure of the leakage detection device equipped with the test circuit most widely used in the prior art is shown. [0003] in the image 3 Among them, 1 is an earth leakage circuit breaker, R, S, and T are power supply side terminals of the earth leakage circuit breaker 1, and U, V, W are load side terminals corresponding to power supply side terminals R, S, and T, respectively. The earth leakage circuit breaker 1 internally includes a main circuit 2 constituted by three-phase conductors connected to ...

AI Technical Summary

Problems solved by technology

[0018] But, in this existing device, because be provided with the connecting line f that is used to connect the test coil 11 of zero-phase converter 4 and the grounding line a of rectifier circuit 10, this connecting line f becomes antenna, there is noise that is harmful to emission electromagnetic wave. The disadvantage of poor resistance

That is, when the emitted electromagnetic wave noise is induced by the ground wire a through the connecting wire f, the potential of the ground wire a fluctuates, the leakage detection sensitivity changes, and the problem of instability occurs.

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