Circuit-breaker automatic closing contact device with high breaking capacity

Abstract

The invention relates to a circuit-breaker automatic closing contact device with high breaking capacity, which comprises a contact support, a rotating shaft, a fixed contact, a rotary dual-breakpoint moving contact installed on the contact support and a contact spring. The fixed contact and the moving contact are symmetrically distributed in relative to the rotating shaft, and an operating mechanism and an electromagnetic mechanism respectively drive the contact support to rotate through a control part of the operating mechanism and a control part of the electromagnetic mechanism of the contact device. Spring fixing shafts are symmetrically arranged on a shell on both sides of the contact support, one end of the contact spring is abutted against the shell, the other end is butted upon a torsion spring contact wire of the contact support, and the contact spring applies a torsion spring force to the contact support in the contact closing direction through the torsion spring contact wire. The automatic closing contact device without exogenic action has high breaking capacity, minimizes the influence of the contact spring on the breaking resistance of the moving contact while not reducing the reliable closing property of the contact, increases the breaking speed and the reliability of the contact and reduces arcing risk.

Description

technical field [0001] The invention relates to a contact device of a low-voltage circuit breaker, in particular to a rotary type automatic closing contact device with double breakpoints in series. Background technique [0002] Breaking capacity is a very important performance index of low-voltage circuit breakers. In order to improve the breaking capacity, the circuit breaker in the prior art, especially the selective protection circuit breaker, adopts an automatic closing contact device with rotary series double breakpoints. The so-called rotary type means that the moving contact closes / breaks with the static contact in the form of rotating motion. The so-called double break point in series refers to the closing / breaking of two moving contacts and two static contacts respectively. The so-called automatic closing means that the contact device can automatically close relying on the elastic force of its own contact spring without external force. Although the automatic clos...

AI Technical Summary

Problems solved by technology

As the contact opening distance of the above-mentioned automatic closing contact increases, the contact spring has a greater influence on the deceleration of the moving contact opening speed, that is, after the elastic deformation of the contact spring increases, the torque of the contact spring also increases. will increase, but because the force arm 1 of the contact spring in the prior art will not change, and the angle of the contact spring’s force on the moving contact (or contact support) will not change, so the contact spring The resistance acting on the moving contacts will increase continuously with the increase of the opening distance between the moving and static contacts, thereby significantly reducing the breaking speed of the moving and static contacts, prolonging the arcing time, and greatly reducing the breaking capacity

Especially in the face of large fault currents, the adverse effects of the existing technology on the breaking speed of the contacts will not be able to ensure safe and reliable breaking of the circuit, and it is also easy to generate arcs between the moving and static contacts, resulting in damage to the contacts. Affect the current limiting effect, etc.

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