A. Phase to phase winding resistance
B. Stator winding to earthed frame
C. Rotor winding to earthed shaft
D. All of the above
0
The speed of a synchronous motor:
0
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. increases as the load increases
B. decreases as the load decreases
C. always remains constant
D. none of the above
0
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. augments it directly
B. directly opposes it
C. cross-magnetises it
D. none of the above
0
Change of D.C. excitation of a synchronous motor changes:
A. become more
B. become less
C. remain constant
D. none of the above
0
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. applied voltage of the motor
B. power factor of power drawn by the motor
C. motor speed
D. none of the these
E. all of the these
0
An important advantage of a synchronous motor over wound round induction motor is that
A. zero degree
B. two degrees
C. five degrees
D. ten degrees
0
The angle between the rotating stator flux and rotor poles is called _________ angle.
A. its power factor may be varied at will
B. its speed is independent of supply frequency
C. its speed may be controlled more easily
D. none of the above
0
Slip-rings in a synchronous motor carry____________?
A. synchronizing
B. obtuse
C. torque
D. power factor
0
A synchronous motor working at leading power factor can be used as____________?
A. direct current
B. alternating current
C. no current
D. all of the above
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