How does a magnetic circuit breaker detect excessive current?

A magnetic circuit breaker detects excessive current using an electromagnet that trips a mechanism. When the current flowing through the circuit exceeds a predetermined level, it causes an increase in the magnetic field generated by the current. This heightened magnetic field activates an electromagnet within the breaker. As the magnetic force grows stronger, it ultimately reaches a threshold where it trips a mechanical lever or mechanism, disconnecting the electrical circuit to protect it from damage caused by overload conditions.

This method allows for rapid disconnection, providing immediate protection against potential circuit damage due to high current levels, ensuring safety in electrical systems. The use of an electromagnet is particularly effective in situations where the current varies quickly, as it can respond almost instantaneously to overload conditions, unlike other options that are slower or less reliable.