MCQ Circuit Breakers Part - 1

Q.1. A circuit breaker normally operates ......

(a) When the power is to be supplied

(b) When the line is to be tested

(c) When the switch is to be put on

(d) Whenever fault occurs in the line

Ans. (d) Whenever fauult occurs in the line

Q.2. The fluids used in the circuit breakers should be of ......

(a) High dielectric strength and thermal stability

(b) Non inflammable

(c) Arc extinguishing ability

(d) All of the above

Ans. (d) All of the above

Q.3. In a circuit breaker, the current that exists at the instant of contact separation is called the ...... current.

(a) Restriking

(b) Breaking

(c) Arc

(d) Recovery

Ans. (b) Breaking

Q.4. In circuit breakers, oil as quenching medium has the advantage of ......

(a) Good cooling properties and absorption of arc energy

(b) High dielectric strength

(c) Acting as an insulator

(d) All of the above

Ans. (d) All of the above

Q.5. Which one of the following circuit breakers are generally used in railway electrification?

(a) Air blast circuit breaker

(b) Minimum oil circuit breaker

(c) Bulk circuit breaker

(d) Sulphur hexafluoride circuit breaker

Ans. (a) Air blast circuit breaker

Q.6. Main purpose of oil in OCB is to ......

(a) Provide insulation

(b) Provide cooling of contacts

(c) Quenching arc

(d) None of the above

Ans. (c) Quenching

Q.7. In a minimum oil circuit breaker, the oil is used

(a) To act as circuit breaking medium only

(b) For circuit breaking and providing insulation

(c) For providing insulation only

(d) For none of the above purposes

Ans. (a) To act as circuit breaking medium only

Q.8. What is the preferred type of "circuit breaker" to be installed in extra high voltage A.C. system?

(a) Bulk oil type circuit breaker

(b) Air blast circuit breaker

(c) Vacuum circuit breaker

(d) Sulpher hexafluoride circuit breaker

Ans. Sulphur hexafluoride circuit breaker

Q.9. Which of the following circuit breakers has high reliability and negligible maintenance?

(a) Air blast circuit breaker

(b) Sulphur hexafluoride circuit breaker

(c) Oil circuit breaker

(d) Vacuum circuit breaker

Ans. (b) Sulphur hexafluoride circuit breaker

Q.10. Which of the following circuit breakers take minimum time in installation?

(a) Air blast

(b) Minimum oil

(c) Bulk oil

(d) Sulphur hexafluoride

Ans. (d) Sulphur hexafluoride