The power developed by a synchronous motor will be maximum when the load angle is____________?

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 coupling angle or load angle of synchronous motor is defined as the angle between the__________?

   A. rotor and stator teeth
   B. rotor and the stator poles of opposite polarity
   C. rotor and the stator poles of the same polarity
   D. none of the above

3. A synchronous motor develops maximum power when load angle is____________?

   A. 45°
   B. 60°
   C. 90°
   D. 120°

4. The maximum power developed in a synchronous motor occurs at a coupling angle of____________?

   A. 30°
   B. 60°
   C. 90°
   D. 180°

5. 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

6. 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

7. A synchronous motor can be used as a synchronous capacitor when it is____________?

   A. under-loaded
   B. over-loaded
   C. under-excited
   D. over-excited

8. In a synchronous motor, the maximum power developed depends on all of the following except:

   A. rotor excitation
   B. maximum value of coupling angle
   C. direction of rotation
   D. supply voltage

9. The maximum power developed in a synchronous motor will depend on__________?

   A. the rotor excitation only
   B. the supply voltage only
   C. the rotor excitation and supply volt-age both
   D. the rotor excitation, supply voltage and maximum value of coupling angle (90°)
   E. none of the above

10. If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor__________?

    A. become more
    B. become less
    C. remain constant
    D. none of the above