Residual current circuit breaker

Abstract

The invention discloses a leakage circuit breaker which has a simple and small structure of a test circuit and can simultaneously perform accurate leakage tests. As a power supply circuit for supplying power to the leakage detection circuit in the leakage circuit breaker, a power supply circuit with a constant current circuit that converts the AC current supplied from the main circuit into a DC current and supplies a constant DC current to the leakage detection circuit is used, and the test resistance The elements are arranged in series in the circuit connecting the main circuit and the AC input end of the current stabilizing circuit, and the test coil of the zero-phase converter is connected to both ends of the resistance element through a test switch to form a leakage test circuit.

Description

technical field [0001] The present invention relates to an earth leakage circuit breaker for detecting electric leakage occurring in a power distribution system connected to motors and various other loads to prevent contagious accidents, and in particular to an improvement of the test circuit. Background technique [0002] In order to accurately test the operation of the earth leakage circuit breaker, various efforts have been made on the leakage test circuit of the earth leakage circuit breaker. One example thereof is shown in Patent Document 1. Figure 7 The structure of the earth leakage circuit breaker shown in this patent document 1 is shown in . [0003] Figure 7 The earth leakage circuit breaker has multiple rated voltages, for example, there are three rated voltages of 100, 200 and 400V. The leakage circuit breaker 1 shown in the figure has a power supply side connection terminal 3A and a load side connection terminal 3B, and in the main circuit connected between t...

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Problems solved by technology

[0009] However, in such a conventional device, since it is necessary to set the number of current-limiting resistance elements and selection switches corresponding to the type of rated voltage used, the installation space of the test circuit increases and the number of parts decreases. increase, there is a problem that the manufacturing cost increases

[0010] Moreover, especially when the rated voltage is high, a large voltage is often applied between the contacts when the test switch is turned on, so it is necessary to increase the contact interval of the test switch to improve the withstand voltage, so there is still the problem of increasing the size of the switch.

[0011] In an earth leakage circuit breaker having such a latter test circuit, when the rat...

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