Circuit Breakers Interview Questions and Answers:

1. What do you understand by switchgear ?

Ans. The apparatus employed for switching, controlling and protecting the electrical circuits and equipment is known as switchgear.

2. Which of the gases are employed in commercial gas-blast circuit breakers ?

Ans. SF6 and air are used in commercial gas-blast circuit beakers.

3. Name the materials used for contacts of vacuum circuit breakers ?

Ans. Copper-bismuth, copper-lead, copper-tellurium, copper-thallium, silver-bismuth, silver-lead and silver-tellurium are some of alloys employed as contact materials in vacuum circuit breakers.

4. Name the three problems encountered in HVDC circuit breakers ?

Ans. The three problems encountered in HVDC circuit breakers are:

  • How to create artificial current zero ?
  • How to prevent restriking of arc ?
  • How to dissipate the stored energy ?