Related Questions

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
Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors?
A Low cost
B Wide speed range
C Stability
D High starting torque
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
Synchronous motors are
A Not-self starting
B Self-starting
C Essentially self-starting
D None of the above
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
Mostly, synchronous motors are of
A alternator type machines
B induction type machines
C salient pole type machines
D smooth cylindrical type machines
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
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
A synchronous motor can develop synchronous torque
A when under loaded
B while over-excited
C only at synchronous speed
D below or above synchronous speed
In medium sized induction motors, the slip is generally around
A 0.04 %
B 0.4 %
C 4 %
D 14 %

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