Which of the following motors is non-self starting ?

Related Mcqs:

1. Synchronous motors are generally not self-starting because:

   A. the direction of rotation is not fixed
   B. the direction of instantaneous torque reverses after half cycle
   C. startes cannot be used on these machines
   D. starting winding is not provided on the machines

2. 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

3. The synchronous motor is not inherently self-starting because_______________?

   A. the force required to accelerate the rotor to the synchronous speed in an instant is absent
   B. the starting device to accelerate the rotor to near synchronous speed is absent
   C. a rotating magnetic field does not have enough poles
   D. the rotating magnetic field is produced by only 50 Hz frequency currents

4. A synchronous motor can be made self starting by providing?

   A. damper winding on rotor poles
   B. damper winding on stator
   C. damper winding on stator as well as rotor poles
   D. none of the above

5. 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

6. Which of the following motors will be used in electric clocks?

   A. D.C. shunt motor
   B. D.C. series motor
   C. A.C. induction motor
   D. A.C. synchronous motor

7. 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

8. 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

9. Mostly, synchronous motors are of_____________?

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

10. For power factor correction, synchronous motors operate at____________?

    A. no-load and greatly over-excited fields
    B. no-load and under-excited fields
    C. normal load with minimum excitation
    D. normal load with zero excitation