In the circuit, the circuit breaker acts just as a fuse, but the fuse can only function once, while circuit breakers can be used repeatedly. As long as the current reaches a dangerous level, it can immediately cause an open circuit. the live wire in the circuit is connected to both ends of the switch. When the switch is placed in the on state, current flows from the bottom terminal, sequentially through the electromagnet, moving contactor, static contactor, and finally from the top terminal.
Current can magnetize the electromagnet. The magnetic force generated by the electromagnet increases with the increase of the current. If the current decreases, the magnetic force will also decrease. When the current jumps to a dangerous level, the electromagnet will generate a magnetic force large enough to pull a metal rod connected to the switch linkage. This tilts the moving contactor away from the static contactor, which in turn cuts the circuit. The current is interrupted.
Outdoor vacuum circuit breakers can be used to distribute electrical energy, start asynchronous motors infrequently, and protect power lines and motors. When they have serious overload or short circuit and undervoltage faults, they can automatically cut off the circuit. Their function is equivalent to a fuse switch. Combination with overheating relay etc. And after breaking the fault current, there is generally no need to change parts.