Centrifugal switch disconnects the auxiliary winding of the motor at about ______ percent of synchronous speed?

Related Mcqs:

1. If the centrifugal switch does not open at 70 to 80 percent of synchronous speed of motor, it would result in_________?

   A. damage to the starting winding
   B. damage to the centrifugal switch
   C. overloading of running winding
   D. none of the above

2. A centrifugal switch is used to dis- connect ‘starting winding when motor has___________?

   A. run for about 1 minute
   B. run for about 5 minutes
   C. picked up about 50 to 70 per cent of rated speed
   D. picked up about 10 to 25 per cent of rated speed

3. In split-phase motor auxiliary winding is of___________?

   A. thick wire placed at the bottom of the slots
   B. thick wire placed at the top of the slots
   C. thin wire placed at the top of the slots
   D. thin wire placed at the bottom of the slots

4. In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to_______________?

   A. improve power factor
   B. increase overload capacity
   C. reduce fluctuations in torque
   D. to improve torque

5. If the centrifugal switch of a two-value capacitor motor using two capacitors fails to open then____________?

   A. motor will not come up to speed
   B. motor will not carry the load
   C. current drawn by the motor will be excessively high
   D. electrolytic capacitor will, in all probability, suffer break down

6. In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will_____________?

   A. become unstable
   B. draw excessive armature current and may burn out
   C. fall out of synchronism and come to stand still
   D. run as induction motor

7. The running winding of a single phase motor on testing with meggar is found to be ground. Most probable location of the ground will be___________?

   A. at the end connections
   B. at the end terminals
   C. anywhere on the winding inside a slot
   D. at the slot edge where coil enters or comes out of the slot

8. In A.C. series motor compensating winding is employed to_____________?

   A. reduce the effects of armature reaction
   B. increase the torque
   C. reduce sparking at the brushes
   D. none of the above

9. In which single-phase motor, the rotor has no teeth or winding ?

   A. Split phase motor
   B. Reluctance motor
   C. Hysteresis motor
   D. Universal motor

10. After the starting winding of a single phase induction motor is disconnected from supply, it continues to run only on ______________?

    A. running winding
    B. rotor winding
    C. field winding
    D. compensating winding