Vacuum circuit breaker

As we know vacuum mean the the pressure is maintained below atmospheric pressure( unit : mm Hg ).So the manufacture made a research and development to design the vacuum circuit breaker based on current cannot jump in vacuum condition.

Vacuum Circuit Breaker used the vacuum pressured to extinguish the current arc when it switching.Normally this type of circuit breaker used for medium voltage ( 1 – 35 kV ) power supply.The ampere rating for vacuum circuit breaker is until 3000 ampere.

Vacuum Circuit Breaker have a  high insulating strength and capable to extinguish the current arc for medium voltage power supply.It more safe for switching and environment friendly.It only a vacuum atmosphere.

 Basic operation of Vacuum Circuit Breaker

Vacuum circuit breaker have a two major component.One is a moving contact and one is fix contact.The current arc created when the contact is closed or open due to current flow.

The arc is quickly extinguished using the vacuum atmosphere in the contact chamber and it absorb all of current arc.It also used the fast acting design to reduce the volume electric arc with spring force.Theoretically more fast contact moving,more low volume of electric arc.

Electric arc cannot easier moving in vacuum atmosphere condition and it suitable to control arc for medium and high voltage circuit breaker. If it not reduce for quantity of electric arc,it can cause the serious damage such as explosion and fire due to the high voltage impact.

Vacuum circuit breaker trigger the abnormal condition using Over current Relay (OCR) and Earth Fault Relay (EFR) as a detection device.When shunt trip get the signal,it will energized the mechanism device to cut off the power supply.


Advantage of Vacuum circuit breaker

  • Long life span,compact design and reliable for high voltage power supply.
  • If failure mechanism device,it cannot cause the fire hazards.
  • Environment friendly and not release a gas during or after operation.
  • It capable to interrupt any fault current.
  • Withstand lightning surges.
  • Effective and only used a low supply for control mechanism.
  • Suitable for a many types of application.


  1. haitham hashim says

    Topics are important and the way I am relieved to explain the issue Important information your site the best sites,thanks

  2. Thirunavukarasu says

    Good theory

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