Low voltage circuit breaker and its arc extinguishing chamber

Abstract

The invention provides an arc extinguishing chamber of a low-voltage circuit breaker. The front portion of the arc extinguishing chamber is opposite to a movable contact. The rear portion of the arc extinguishing chamber is an arc outlet. The arc extinguishing chamber of the low-voltage circuit breaker comprises at least two arc chutes stacked up and down and at least one insulating block capableof blocking the arc. Both sides of the each arc chute are fixed by insulating brackets. The insulating block is arranged at the rear portion of the arc extinguishing chamber. The insulating block andthe arc chutes are clamped. The present invention also provides a low-voltage circuit breaker comprising the arc extinguishing chamber of the low-voltage circuit breaker. The arc is rapidly cooled andextinguished by the insulating block and is prevented from burning up again.

Description

technical field [0001] The invention relates to the technical field of low-voltage electrical appliances, in particular to a low-voltage circuit breaker and an arc extinguishing chamber thereof. Background technique [0002] The low-voltage circuit breaker is mainly composed of the shell, the contact system, the arc extinguishing system and the operating mechanism, etc. Among them, the arc extinguishing chamber of the arc extinguishing system is a very important functional part of the low-voltage circuit breaker, and its performance has a great impact on the short-circuit condition of the low-voltage circuit breaker. Reliable breaking down plays a decisive role. [0003] The arc extinguishing grid type arc extinguishing chamber structure adopted by the existing low-voltage circuit breaker is composed of an arc extinguishing grid and partitions fixed on both sides of the arc extinguishing grid. The arc extinguishing grid is a metal grid and the partition is an insulating mate...

AI Technical Summary

Problems solved by technology

[0006] However, the moving and static contacts in the prior art are all located in the center of the arc extinguishing chamber, and because there are narrow slits in the grid, the arc movement area will be concentrated in the middle of the arc extinguishing chamber and near the narrow slit, so the arc has a great impact on the gas generating plate. The burning is limited, especially, the burning of the arc on both sides of the grid is relatively small, and the area of ​​the entire grid is less than 50%. At the same time, limited by the size of the switch, the effective length of the grid is also limited, resulting in the arc from After entering the narrow slit of the grid, it will continue to move forward and run out from the back of the grid, and be connected in series on the back, so that the number of arcs divided by the grid is reduced, the arc voltage is greatly reduced, and the extinguishing of the arc is extremely effective. Unfavorable, moreover, once the arc enters the grid, it is completely cooled by the grid, which lacks the gas cooling effect and is prone to arc reignition

[0007] With the development of electric power, the operating voltage of the power system continues to increase. The AC voltage is as high as 1200V and the DC voltage is as high as 1500V. However, the structure of the arc extinguishing chamber in the prior art cannot provide a higher arc voltage. , it is necessary to develop a circuit breaker arc extinguishing chamber that can provide higher arc voltage, rapid cooling and arc extinguishing

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