Inductors - Technical MCQs

Q1:

A magnetic circuit breaker will open to protect equipment only when:

A voltage is exceeded

B an open is in the equipment

C the equipment is operating properly

D current is exceeded

ANS:D - current is exceeded

Magnetic circuit breakers use a solenoid (electromagnet) whose pulling force increases with the current. Certain designs utilize electromagnetic forces in addition to those of the solenoid. The circuit breaker contacts are held closed by a latch. As the current in the solenoid increases beyond the rating of the circuit breaker, the solenoid's pull releases the latch, which lets the contacts open by spring action.