Insulation resistance of high voltage circuit breakers is more than________________?

Related Mcqs:

1. 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

2. 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

3. 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

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. 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

6. 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

7. 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

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. The voltage appearing across the contacts after opening of the circuit breaker is called__________voltage

   A. recovery
   B. surge
   C. operating
   D. arc
   E. none of the above

10. The arc voltage produced in A.C. circuit breaker is always_____________?

    A. in phase with the arc current
    B. lagging the arc current by 90″
    C. leading the arc current by 90°
    D. none of the above