The mechanical displacement of the rotor with respect to the stator, in polyphase multipolar synchronous motors running at full load, is of the order of_____________?

Related Mcqs:

1. In which of the following motors the stator and rotor magnetic field rotate at the same speed?

   A. Universal motor
   B. Synchronous motor
   C. Induction motor
   D. Reluctance motor

2. In which of the following motors the stator and rotor fields rotate simultaneously?

   A. D.C. motor
   B. Reluctance motor
   C. Universal motor
   D. Synchronous motor
   E. Induction motor

3. When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor___________?

   A. remains same as the original value
   B. decreases to half the original value
   C. tends to becomes zero
   D. increases to two times the original value

4. The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as__________?

   A. locked-rotor torque
   B. synchronous torque
   C. pull up torque
   D. reluctance torque

5. The standard full-load power factor ratings for synchronous motors are___________?

   A. zero or 0.8 leading
   B. unity or 0.8 lagging
   C. unity or 0.8 leading
   D. unity or zero

6. A synchronous motor is running on a load with normal excitation. Now if the load on the motor is increased

   A. power factor as well as armature current will decrease
   B. power factor as well as armature current will increase
   C. power factor will increase but armature current will decrease
   D. power factor will decrease and armature current will increase

7. When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop_________________?

   A. inductor motor torque
   B. induction generator torque
   C. synchronous motor torque
   D. d.c. motor toque
   E. none of the above

8. The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as___________?

   A. pull-up torque
   B. pull-in torque
   C. pull-out torque
   D. none of the above

9. A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will___________?

   A. remain same
   B. go down
   C. improve
   D. none of the above

10. Mostly, synchronous motors are of_____________?

    A. alternator type machines
    B. induction type machines
    C. salient pole type machines
    D. smooth cylindrical type machines