Which motor is normally free from mechanical and magnetic vibrations ?

Related Mcqs:

1. As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for__________?

   A. fans
   B. blowers
   C. sound equipment
   D. mixer grinders

2. In case of a shaded pole motor the direction of rotation of the motor is__________?

   A. from main pole to shaded pole
   B. from shaded pole to main pole
   C. either of the above depending on voltage
   D. either of the above depending on power factor

3. A.C. series motor as compared to D.C. series motor has__________?

   A. smaller brush width
   B. less number of field turns
   C. more number of armature turns
   D. less air gap
   E. all of the above

4. Two-value capacitor motor finds increased application as compressor motor in small home air-conditioners because_____________?

   A. it is comparatively cheaper
   B. it has almost non-destructible capacitor
   C. it has low starting as well as running currents at relatively high power factor
   D. it is quiet in operation

5. 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

6. 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

7. A universal motor can run on___________?

   A. A.C. only
   B. D.C. only
   C. either A.C. or D.C.
   D. none of the above

8. In a two value capacitor motor, the capacitor used for running purposes is_______________?

   A. air capacitor
   B. paper spaced oil filled type
   C. ceramic type
   D. a.c. electrolytic type

9. The speed of a universal motor is generally reduced by using_________?

   A. gear trains
   B. V-belts
   C. brakes
   D. chains

10. A repulsion motor is equipped with__________?

    A. slip rings
    B. commutator
    C. both A. and (b)
    D. none of the above