The function of the electromagnet in a circuit breaker lock is to ensure that the breaker cannot be switched on unintentionally. The mechanism covered by the start button can only be activated through that button. This prevents accidental contact that could cause operational accidents, as well as safety issues such as vehicles failing to start. The closed circuit interlocks with electrical devices like knife switches and load power switches.
The circuit breaker lock electromagnet works together with the external circuit to prevent misoperation of the isolating switch (it can also protect load power switches). The conductive and auxiliary contact points are connected in series in the isolating switch circuit, ensuring that the circuit cannot be easily switched on or off before proper conditions are met. The hydraulic cylinder of the circuit breaker lock electromagnet is installed on one side of the maintenance shaft. If not operating, the hydraulic cylinder locks the contact mechanism, preventing manual operation of the isolating switch. Thus, without requiring a complete power outage, it avoids both accidental electric operations and unnecessary manual intervention.
When the isolating switch (pulley-type power switch) circuit breaker lock electromagnet is energized or the secondary power plug is still inserted, the electromagnet remains engaged, allowing the isolating switch to close. If the secondary power plug is pulled out and the electromagnet is not energized, the iron core disengages, preventing the switch from closing. This design prevents unsafe operations when the secondary circuit is disconnected.
Circuit Breaker Lock
Currently, there are two main types of circuit breaker lock electromagnets:
- Closing-type electromagnet for isolating switches
This type requires the electromagnet to be energized and held before the isolating switch can be opened. It is commonly used in interlock systems between isolating switches. For example, in a single-bus short-circuit system, a double-key isolating switch setup ensures that only one isolating switch can be operated at a time, with the help of this type of interlock. - Vehicle-mounted circuit breaker lock electromagnet
In test sites, only the vehicle-mounted circuit breaker lock electromagnet can supply power. This ensures that when one circuit breaker electromagnet is active, the isolating switch is blocked, and vice versa. During operation, the vehicle-mounted circuit breaker lock electromagnet provides power output only to itself, effectively preventing conflicting operations.