A circuit breaker refers to a switching device that can close, carry, and disconnect current under normal circuit conditions, and can close, carry, and disconnect current under abnormal circuit conditions within a specified time. Circuit breakers are divided into high voltage circuit breakers and low voltage circuit breakers according to their usage scope. The boundary between high and low voltage is relatively vague, and those above 3kV are generally referred to as high voltage electrical appliances.
The function of a circuit breaker:
It can be used to distribute electrical energy, start asynchronous motors infrequently, protect power lines and motors, and automatically cut off circuits when they experience serious overload, short circuit, undervoltage and other faults. Its function is equivalent to a combination of fuse type switches and over/under heat relays. And generally, there is no need to change the components after disconnecting the fault current.
Working principle of circuit breaker:
The main contact of the low-voltage circuit breaker is manually operated or electrically closed. After the main contact is closed, the free release mechanism locks the main contact in the closed position. The coil of the overcurrent release and the thermal element of the thermal release are connected in series with the main circuit, while the coil of the undervoltage release is connected in parallel with the power supply. When a short circuit or severe overload occurs in the circuit, the armature of the overcurrent release will engage, causing the free release mechanism to operate and the main contact to disconnect the main circuit. When the circuit is overloaded, the thermal element of the thermal release generates heat, causing the bimetallic strip to bend and pushing the free release mechanism to move. When the circuit is under voltage, the armature of the undervoltage release is released. Also enables the free release mechanism to operate. The shunt release is used for remote control. During normal operation, its coil is powered off. When distance control is required, press the start button to energize the coil
