There are actually three main tripping methods for air circuit breakers. The first is electromagnetic tripping. The second type is thermal trip. The third type is compound tripping.
Short circuit protection corresponds to electromagnetic tripping. Electromagnetic tripping refers to the fact that in an air circuit breaker, when a load current passes through the coil, the electromagnet attraction force is relatively small. When a short-circuit current passes through, the suction force is relatively large, which causes the armature to move to drive the release device, thereby tripping and cutting off the power.
Overload protection corresponds to thermal trip. Thermal trip means that in an air circuit breaker, when an overload occurs in the circuit, the overload current can cause the components in the switch to generate a certain amount of heat, and the heat generated will cause the bimetal to deform, causing the trip to occur. The device trips, and then the circuit can be disconnected. Compound tripping, the composite tripping in air circuit breakers generally uses metal sheets. When the circuit knows that the current reaches a certain load current, it will generate heat, and this heat will also deform the metal sheet, which can cause degassing tripping, which can disconnect the power supply.
At the same time, when a large short-circuit current flows through the coil in the air circuit breaker, the tripper also operates. Therefore, the compound tripper can provide both short-circuit protection and overload protection.
Air circuit breaker is a very commonly used and particularly important electrical appliance in our low-voltage power grid. It combines control and multiple protections into one. In addition to completing the connection and disconnection of circuits, it can also protect circuits and electrical equipment from short circuits, overloads, and undervoltages. It can also be used to start the motor infrequently.
Commonly used air circuit breakers in our homes are ordinary air circuit breakers, so the internal tripping curves of these air circuit breakers are basically determined at the factory. Therefore, the arc extinguishing capabilities of these air circuit breakers are also certain. However, if a professional can fine-tune the internal spring of the air circuit breaker, the arc extinguishing speed can be increased, but the arc extinguishing ability cannot be improved.
