A synchronous motor can develop synchronous torque:

Related Mcqs:

1. 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

2. The ratio of starting torque to running torque in a synchronous motor is____________?

   A. zero
   B. one
   C. two
   D. infinity

3. The maximum value of torque that a synchronous motor can develop without losing its synchronism, is known as_____________?

   A. slip torque
   B. pull-out torque
   C. breaking torque
   D. synchronising torque

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. While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerating torque is produced by_____________?

   A. induction motor torque in field winding
   B. induction motor torque in damper winding
   C. eddy current and hysteresis torque in pole faces
   D. reHetance motor torque due to saliency of the rotor
   E. all of the above methods

6. In a 3-phase, 4-pole, 50 Hz synchronous motor, the frequency, pole number and load torque all are halved. The motor speed will be____________?

   A. 3000 r.p.m.
   B. 1500 r.p.m.
   C. 750 r.p.m.
   D. none of the above

7. When V is the applied voltage, then the breakdown torque of a synchronous motor varies as_________?

   A. V
   B. V312
   C. V2
   D. 1/V

8. If load (or torque) angle of a 4-pole synchronous motor is 6° electrical, its value in mechanical degrees is__________?

   A. 2
   B. 3
   C. 4
   D. 6

9. The torque angle, in a synchronous motor, is the angle between_______________?

   A. the supply voltage and the back e.m.f.
   B. magnetising current and back e.m.f.
   C. the rotating stator flux and rotor poles
   D. none of the above

10. In a synchronous motor, the breakdown torque is__________?

    A. directly proportional to the square of the applied voltage
    B. directly proportional to applied voltage
    C. inversely proportional to applied voltage
    D. none of the above