Field breakers had been popular in Power Plant Generator. Field control applications due to their very fast operation time ( Closing and Tripping) also isolate generator fields from the source i.e Thyristor Bridges.

In case of an internal fault in the generator rapid de-excitation is necessary to minimize the fault power level. For isolating the power source to be generator field winding a generator field circuit breaker has been used and “a make before break” contact connects discharge resistance across the field winding for dissipating inductive energy stored in the field winding.

The winding of synchronous machines or exciter machines is normally fed via a special and direct current circuit breaker so that in case of disturbance definite disconnection from the supply source and subsequent discharge of energy in the magnetic circuit takes place.

Field Breaker servicing is required to avoid damages around the contactors.