Circuit Breaker

With the advancement of power system, the lines and their equipment operate at very high voltages and carry large current. The arrangement of switches along with fuses cannot serve the desired function of switch gear in such high capacity circuits. This necessitates employing a more dependable means of control such as is obtained by the use of circuit breakers. A circuit breaker can make or breaker a circuit either manually or automatically under all conditions ie no-load, full-load and short circuit conditions. This characteristic of the circuit breaker has made it very useful equipment for switching and protection of various parts of the power system.

Fig: Circuit Breaker

Operating Principle

A circuit breaker essentially consist of fixed and moving parts contacts, called electrodes. Under normal condition these contacts remain closed and will not open automatically until and unless the system becomes faulty. Of course the contacts can be opened manually or by remote control whenever desired. When a fault occur on any part of the system the trip coils of the circuit breaker get energized and the moving contacts are pulled apart by some mechanism, thus opening the circuit.
When the contacts of a circuit breaker are separated under fault conditions, an arc is struck between them. The current is thus able to continue until the discharge ceases. The production or arc not only delays the current interruption process but it also generates enormous heat which may cause damage to the system or to the circuit breaker itself. Therefore, the main problem in a circuit breaker is to extinguish the arc within the shortest possible time so that heat generated by it may not reach a dangerous value.


  • Air Break Circuit Breaker
  • Air Blast Circuit Breaker
  • Sluphur Hexafluoride (SF6) Circuit Breaker
  • Minimum oil and Bulk Oil Circuit Breaker
  • Vacuum Oil Circuit Breaker

Share on Google Plus

About shaikat

This is a short description in the author block about the author. You edit it by entering text in the "Biographical Info" field in the user admin panel.
    Blogger Comment
    Facebook Comment
Related Posts Plugin for WordPress, Blogger...

Featured Post


A proportional-integral-derivative controller ( PID controller ) is a control loop feedback mechanism used in power and industrial con...


Recent Posts Widget