Circuit breakers are essentially______________?

Related Mcqs:

1. Circuit breakers are essentially____________?

   A. current carrying contacts called electrodes
   B. arc extinguishers
   C. circuits to break the system
   D. transformers to isolate the two systems
   E. any of the above

2. Circuit breakers usually operate under______________?

   A. transient state of short-circuit current
   B. sub-transient state of short-circuit current
   C. steady state of short-circuit current
   D. after D.C. component has ceased

3. The current zero interruption, in oil and air blast circuit breakers, is achieved by_______________?

   A. lengthening of the gap
   B. cooling and blast effect
   C. both A. and B
   D. deionizing the oil with forced air
   E. none of the above

4. The current zero interruption, in oil and air blast circuit breakers, is achieved by____________?

   A. lengthening of the gap
   B. cooling and blast effect
   C. both (A) and (B)
   D. deionizing the oil with forced air
   E. none of the above

5. The time of closing the cycle, in modern circuit breakers is_____________?

   A. 0.003 sec
   B. 0.001 sec
   C. 0.01 sec
   D. 0.10 sec
   E. none of the above

6. Insulation resistance of high voltage circuit breakers is more than________________?

   A. 1 mega ohms
   B. 10 mega ohms
   C. 100 mega ohms
   D. 500 mega ohms

7. Which of the following circuit breakers has high reliability and minimum maintenance ?

   A. Air blast circuit breakers
   B. Circuit breaker with SF6 gas
   C. Vacuum circuit breakers
   D. Oil circuit breakers

8. Air blast circuit breakers for 400 kV power system are designed to operate in_______________?

   A. 100 microsecond
   B. 50 millisecond
   C. 0.5 sec
   D. 0.1 sec

9. In a circuit breaker the basic problem is to________________?

   A. maintain the arc
   B. extinguish the arc
   C. transmit large power
   D. emit the ionizing electrons

10. Short-circuit currents are due to_______________?

    A. single phase to ground faults
    B. phase to phase faults
    C. two phase to ground faults
    D. three phase faults
    E. any of these