Circuit breaker with selectivity

Abstract

The invention provides a circuit breaker used in a power distribution system, which includes a circuit breaker circuit. The circuit breaker circuit includes an overload release, a magnetic release system, a main contact, an auxiliary contact and an operating mechanism. The operating mechanism operates normally Controls the closing or cutting of the main contacts and auxiliary contacts under working and overload fault conditions. The circuit breaker also includes an electronic tripping accessory circuit, which includes a selective resistor and an electronic tripper connected in series. The selective resistor and electronic tripper are connected in series with at least the main contact in the first pole of the circuit breaker. The input circuit part of the magnetic tripping system is connected in parallel. In the event of a short-circuit fault, the main contacts are disconnected under the push of the magnetic tripping system, allowing the short-circuit current to flow through the auxiliary contacts, selective resistors and electronic releases. , the electronic tripper selectively controls the operating mechanism according to whether the short-circuit fault is eliminated within a predetermined delay time, and then the operating mechanism controls the main contact and the auxiliary contact to perform corresponding closing or cutting operations.

Description

technical field [0001] The present invention relates to a circuit breaker, in particular to a low-voltage miniature circuit breaker capable of providing three-stage fault protection including overload protection, short-circuit delay protection, and short-circuit instantaneous protection, so as to realize miniature protection of lower-level terminals in power distribution networks. Circuit breaker selectivity. Background technique [0002] With the development of electrical automation, miniature DC circuit breakers have become an electrical appliance widely used in low-voltage terminal power distribution systems. It can usually ensure the connection and disconnection under the rated current, voltage and load required by various users. When there is any abnormal fault in the circuit (such as overload or short circuit), it can disconnect the protected circuit by disconnecting the moving contact from the static contact, so that the load can be completely isolated from the power...

AI Technical Summary

Problems solved by technology

This has greatly affected the continuity of power supply of various power distribution systems, especially the continuity of power supply of residential power distribution systems.

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