Computer Programming MCQs

5739 MCQs  (Page 89 of 574)

If the field circuit of an unloaded salientpole synchronous motor gets suddenly open-circuited, then
A. It runs at a slower speed
B. The motor stops
C. It continues to run at the same speed
D. It runs at a very high speed
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
A rotory converter can also be run as a___________?
A. d.c. shunt motor
B. d.c. series motor
C. d.c. compound motor
D. induction motor
In a 3-phase synchronous motor, the negative phase sequence exists when the motor is_______________?
A. Supplied with unbalanced voltage
B. Under-loaded
C. Over-loaded
D. None of the above
In a synchronous motor, damper windings are provided on____________?
A. Stator frame
B. Rotor shaft
C. Pole faces
D. None of the above
The net armature voltage of a synchronous motor is equal to the_______________?
A. Vector sum of eb and v
B. Arithmetic sum of eb and v
C. Arithmetic difference of eb and v
D. Vector difference of eh and v
A 3-phase synchronous motor is running clockwise. If the direction of its field current is reversed
A. The motor will stop
B. The motor continue to run in the same direction
C. The winding of the motor will burn
D. The motor will run in the reverse direction
The torque angle, in a synchronous motor, is the angle between_______________?
A. The supply voltage and the back e.m.f.
B. Magnetising current and back e.m.f.
C. The rotating stator flux and rotor poles
D. None of the above
By which of the following methods the constant speed of a synchronous motor can be changed to new fixed value ?
A. By changing the supply frequency
B. By interchanging any two phases
C. By changing the applied voltage
D. By changing the load