Miniature circuit breaker

Abstract

The invention discloses a miniature circuit breaker, which belongs to the technical field of low-voltage apparatus. The miniature circuit breaker comprises a moving contact which is mounted in a shell and electrically connected with a first wiring terminal, a static contact which is also mounted in the shell and electrically connected with a second wiring terminal, an arc chute piece which is located in the shell and used for extinguishing the electric arc generated when the moving and static contacts are separated, a moving contact arc striking plate which is corresponding to the moving contact and one end of which is extended to the arc chute piece and the other end is electrically connected with the first wiring terminal, and an electromagnetic coil and thermal element which are distributed on the same side of the moving contact, wherein the electromagnetic coil and the thermal element are connected in series and then connected in series between the moving contact and the first wiring terminal. The invention has the advantages that: the breaking capacity and the electric service life of the miniature circuit breaker are remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of low-voltage electrical appliances, and in particular relates to a miniature circuit breaker. Background technique [0002] The miniature circuit breaker is configured in the low-voltage power grid to limit or disconnect the fault current in the circuit. When a large current such as caused by a short circuit occurs in the circuit, the moving contact arranged opposite to the static contact moves in the direction of opening under the action of the electric repulsion, and an arc will be generated when the moving and static contacts are separated, and the arc is in the self-excited magnetic field Driven by the driving force, it enters the arc extinguishing chamber and extinguishes, so that the short-circuit current is broken. In order to limit the rise of the short-circuit current and improve the breaking capacity, it is a common method to connect the current-limiting resistor in series in the main circuit of...

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Problems solved by technology

[0007] The applicant has searched, but in published patent literature such as CN1610039A (the arc extinguishing device of the circuit breaker), CN1209777C (the arc extinguishing device of the circuit breaker) and CN1988097A (the arc extinguishing device of the molded case circuit breaker) etc. all do not give The technical enlightenment that can effectively and significantly improve the current limiting capacity of the miniature circuit breaker current limiting resistor

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