The key connection points for circuit breakers in plastic housings for electronics are manual operation or motorized connections. After the main connection is turned off, the free trip mechanism locks the main connection at the terminal. The electromagnetic coil of the overcurrent release and the thermal components of the thermal release are connected in series with the main circuit, while the electromagnetic coil of the undervoltage release and the power supply are connected in parallel.
When the circuit of the electronic device molded circuit breaker is short-circuited or under heavy load, the solenoid of the overcurrent release is activated, causing the main contacts to disconnect the main circuit via the trip-free mechanism.
When the circuit is overloaded, the thermal components of the thermal release heat up, and the bimetallic strip bends, triggering the trip-free mechanism to break the main circuit.
When the supply voltage is insufficient, the solenoid of the undervoltage release de-energizes, activating the trip-free mechanism to disconnect the main contacts.
Pressing the shunt trip button energizes its solenoid, forcing the trip-free mechanism to open the main circuit.
Classification by arc-extinguishing medium:
● Air circuit breaker: Uses atmospheric air
● Inert gas breaker: SF6 or similar gases
● Oil circuit breaker: Mineral oil insulation
Key difference: Leakage protection molded case breakers integrate ground fault detection (30mA–3A sensitivity) alongside standard protections.