In a hysteresis motor, the rotor must have____________?

Related Mcqs:

1. The rotor of a hysteresis motor is made of___________?

   A. aluminium
   B. cast iron
   C. chrome steel
   D. copper

2. The direction of rotation of an hysteresis motor is determined by____________?

   A. interchanging the supply leads
   B. position of shaded pole with respect to main pole
   C. retentivity of the rotor material
   D. none of these

3. A hysteresis motor works on the principle of__________?

   A. hysteresis loss
   B. magnetisation of rotor
   C. eddy current loss
   D. electromagnetic induction

4. Which of the following statements regarding hysteresis motor is in incorrect?

   A. It is extremely sensitive to fluctuations in supply voltage
   B. Its high starting torque is due to its high rotor hysteresis loss
   C. It is extremely quiet in operation
   D. It accelerates from rest to full-speed almost instantaneously

5. Hysteresis motor is particularly useful for high-quality record players and tape-recorders because___________?

   A. it revolves synchronously
   B. it is not subject to any magnetic or mechanical vibrations
   C. it can be easily manufactured in extremely small sizes of up to 1 W output
   D. it develops hysteresis torque which is extremely steady both in amplitude and phase

6. The rotor developed by a single-phase motor at starting is___________?

   A. more than i.he rated torque
   B. rated torque
   C. less than the rated torque
   D. zero

7. 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

8. Locked rotor current of a shaded pole motor is____________?

   A. equal to full load current
   B. less than full load current
   C. slightly more than full load current
   D. several times the full load current

9. The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it_____________?

   A. improves the efficiency
   B. helps the rotor teeth to remain under the stator teeth
   C. helps in reducing the tendency of the rotor teeth to remain under the stator teeth
   D. improves the power factor

10. 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