Contact and arc extinguishing system for universal type low-voltage circuit breaker

Abstract

The invention relates to a contact and an arc extinguishing system for a universal type low-voltage circuit breaker. The contact and the arc extinguishing system for the universal type low-voltage circuit breaker comprise a moving contact, a stationary contact, a stationary contact arc striking board, a moving contact arc striking board, an arc extinguishing grille sheet set composed of a plurality of grille sheets and a contact arc extinguishing system composed by an air outlet channel and an air outlet at the upper end of the arc extinguishing grille sheet set, wherein, the moving contact, the stationary contact, the stationary contact arc striking board, the moving contact arc striking board and the arc extinguishing grille sheet set are fixed on a moving conducting rod. A middle grille sheet in the arc extinguishing grille sheet set extends to the direction of the contacts and protrudes forwards. Due to the fact that the middle grille sheet in the arc extinguishing grille sheet set extends to the direction of a contact area, an electric arc contacts the extended grille sheet in advance in the process of moving to an arc extinguishing chamber, and under guidance of the grille sheet, the electric arc enters into other grille sheets in the rear portion smoothly. According to the structure, due to the fact that only one grille sheet is extended, a contact area magnetic field is slightly influenced, and short time tolerant property of the circuit breaker is not influenced. Due to the fact that the extended grille sheet can divide an air stream entering into the arc extinguishing chamber into two streams, namely, a front stream and a rear stream, in the process of breaking, drive action of the air flow to the electric arc is improved, the electric arc is pushed to enter into the arc extinguishing chamber of grille sheets and opening and breaking performance of the circuit breaker is improved.

Description

【Technical field】 [0001] The invention belongs to the field of low-voltage electrical appliances, in particular to a contact and arc extinguishing system of a universal low-voltage circuit breaker. 【Background technique】 [0002] The universal low-voltage circuit breaker is used as the main switch in the low-voltage power distribution system. It can switch on and off the distribution line under rated load, automatically disconnect the circuit under fault conditions (such as overload and short circuit), and rely on dynamic, The static contacts are separated to realize load and power isolation. Universal low-voltage circuit breakers generally belong to class B circuit breakers with selective protection (national standard GB14048-2), so its protection characteristics have a short delay function, and it has a short-term withstand current requirement, that is, in When the line is short-circuited, the circuit breaker will not be repelled by the electric repulsion during the time ...

AI Technical Summary

Problems solved by technology

In order to improve the short-term withstand capacity, the traditional universal circuit breaker design with selection function, the arc extinguishing iron grid is far away from the contact system, so as to reduce the magnetic field and electromagnetic repulsion that cause the contacts to repel. This design brings The problem is that the arc between the contacts lacks the driving force of the magnetic field, and the airflow field formed by the flat moving contact arc striker is not smooth, which makes it difficult for the arc to enter the arc extinguishing grid, which affects the breaking performance of the circuit breaker

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