- A. no slip-rings
- B. one slip-ring
- C. two slip-rings
- D. three slip-rings
Synchronous Motors
-
A three-phase synchronous motor will have
-
A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because
- A. synchronous motor has no slip
- B. stator supply is not required to produce magnetic field
- C. mechanical load on the rotor remains constant
- D. synchronous motor has large airgap
-
The armature current of the synchronous motor
- A. has large values for low excitation i niy
- B. has large values for high excitation only
- C. has large values for low and high excitation
- D. any of the above
-
A pony motor is basically a
- A. small induction motor
- B. D.C. series motor
- C. D.C. shunt motor
- D. double winding A.C./D.C. motor
-
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
-
The shaft of synchronous motor is made of
- A. mild steel
- B. chrome steel
- C. alnico
- D. stainless steel
-
Mostly, synchronous motors are of
- A. alternator type machines
- B. induction type machines
- C. salient pole type machines
- D. smooth cylindrical type machines
-
Which of the following methods is used to start a synchronous motor ?
- A. Damper winding
- B. Star-delta starter
- C. Damper winding in conjunction with star-delta starter
- D. Resistance starter in the armature circuit
-
The angle between the rotating stator flux and rotor poles is called _____ angle.
- A. torque
- B. obtuse
- C. synchronizing
- D. power factor
-
The operating speed of a synchronous motor can be changed to new fixed value by
- A. changing the load
- B. changing the supply voltage
- C. changing frequency
- D. using brakes