Arc extinguishing cover for small circuit breaker14

Arc extinguishing cover for small circuit breakers is a safety device for small circuit breakers (such as miniature circuit breakers, air switches, etc.), which is mainly used to quickly cut off the current and effectively extinguish the arc when a short circuit or overload occurs in the circuit. Arc refers to the high-temperature, high-energy discharge phenomenon formed by the current passing through the air or other media when the current is interrupted, which may cause safety hazards such as equipment damage and fire.

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Product Description

If the arc extinguishing hood of a small circuit breaker fails to extinguish the arc properly, it may cause damage to the switch, leading to more serious electrical failures. The main reasons for arc extinguishing system failure are as follows:

1.Arc extinguishing cover is damp

Arc chute is usually made of asbestos cement board or fiberboard, which is easily affected by moisture. Once damp, the insulation performance of the arc chute will be significantly reduced, resulting in the arc cannot be effectively elongated. In addition, when the arc burns, the high temperature will vaporize the moisture in the arc chute, causing the pressure inside the chute to increase, thereby hindering the arc from entering the arc chute and prolonging the arc extinguishing time. It is relatively simple to judge this fault: under normal circumstances, the arc spray range is large, accompanied by a weak "pop, pop" sound; if the contact is severely burnt or the arc chute is burnt, it means that the arc chute has been damp. At this time, you only need to dry the arc chute to restore its function.

2.Carbonization of arc extinguishing hood

In a high temperature environment, the surface of the arc extinguishing hood may be charred, forming a carbon conductive bridge, which is extremely detrimental to the arc extinguishing effect, so it needs to be treated in time. The treatment method is to use a fine file to gently file away the carbonized part, but be careful not to increase the surface roughness, because the rough surface will increase the resistance of the arc.

3.Magnetic blow coil short circuit

In order to guide the arc into the arc extinguishing hood, some switches use magnetic blow-out coils. These coils are usually insulated with air, without additional insulating materials. If the coil is deformed by collision or too much conductive dust accumulates, it may cause the coil to short-circuit or short-circuit between turns, making the coil unable to work normally and reducing the arc extinguishing performance of the switch.

4.Arc quenching grid damage

The falling off or rusting of the metal arc-extinguishing grid will affect the smooth introduction of the arc and thus the arc-extinguishing effect, so it should be repaired in time. Although the arc-extinguishing grid looks like copper, it is actually mostly steel with only a layer of copper on the surface. The damaged grid can be replaced with ordinary tinplate.

5.Arc extinguishing contact failure

The main function of the arc extinguishing contact is to guide the arc to protect the main contact. Its basic working principle is: the arc extinguishing contact closes before the working contact and opens after the working contact. If the arc extinguishing contact is severely worn or improperly assembled, it will lose its protective function, so it needs to be checked and adjusted regularly.

By understanding the causes of these faults, the arc extinguishing hoods of small circuit breakers can be better maintained and managed to ensure the safe and reliable operation of electrical equipment.