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

Related Mcqs:

1. 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

2. 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_____________?

   A. zero degree
   B. two degrees
   C. five degrees
   D. ten degrees

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 angle between the rotating stator flux and rotor poles is called _________ angle.

   A. synchronizing
   B. obtuse
   C. torque
   D. power factor

5. 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

6. 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

7. Which of the following losses is not dissipated by the stator core surface in a synchronous motor?

   A. Eddy current losses in the conductors
   B. Iron losses in the stator
   C. Copper losses in the slot portion of the conductors
   D. Windage losses
   E. None of the above

8. When a 3-phase synchronous generator is supplying a zero power factor lagging load, the armature field affects the main field in the following way

   A. augments it directly
   B. directly opposes it
   C. cross-magnetises it
   D. none of the above

9. In a synchronous motor, the magnitude of stator back e.m.f. Eb depends on___________?

   A. load on the motor
   B. d.c. excitation only
   C. both the speed and rotor flux
   D. none of the above

10. The back e.m.f. in the stator of a synchronous motor depends on____________?

    A. number of poles
    B. flux density
    C. rotor speed
    D. rotor excitation
    E. none of the above