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

Related Mcqs:

1. The arcing contacts in a circuit breaker are made of______________?

   A. copper tungsten alloy
   B. porcelain
   C. electrolytic copper
   D. aluminium alloy

2. 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

3. In order that current should flow without causing excessive heating or voltage drop, the relay contacts should_________________?

   A. have low contact resistance
   B. be clean and smooth
   C. be of sufficient size and proper shape
   D. have all above properties

4. The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to______________?

   A. lubricate the contacts
   B. insulate the contacts from switch body
   C. extinguish the arc
   D. all of the above
   E. none of the above

5. With which of the following, a circuit breaker must be equipped for remote operation ?

   A. Inverse time trip
   B. Time-delay trip
   C. Shunt trip
   D. None of the above
   E. All of the above

6. Which of the following medium is employed for extinction of arc in air circuit breaker?

   A. Water
   B. Oil
   C. Air
   D. SF6

7. Air blast circuit breaker is used for_____________?

   A. over currents
   B. short duty
   C. intermittant duty
   D. repeated duty

8. Ionization in circuit breaker is facilitated by___________?

   A. high temperature
   B. increase of mean free path
   C. increasing field strength
   D. all of the above

9. Arc in a circuit breaker is interrupted at___________?

   A. zero current
   B. maximum current
   C. minimum voltage
   D. maximum voltage

10. The information to the circuit breaker under fault conditions is provided by____________?

    A. relay
    B. rewirable fuse
    C. H.R.C. only
    D. all of the above