Working Principle of Circuit Breaker The circuit breaker mainly consists of fixed contacts and moving contacts. In normal "ON" condition of the circuit breaker, these two contacts are physically connected to each other due to applied mechanical pressure on the moving contacts.
Non-puffer piston circuit breaker; Single- puffer piston circuit breaker. Double-puffer piston circuit breaker. The circuit breaker which used air and oil as an insulating medium, their arc extinguishing force builds up was relatively slow after the movement of contact separation.
This type of circuit breakers, is those kind of circuit breaker which operates in air at atmospheric pressure. After development of oil circuit breaker, the medium voltage air circuit breaker (ACB) is replaced completely by oil circuit breaker in different countries.