The oscillations in a synchronous motor can be damped out by_______________?
A. maintaining constant excitation
B. running the motor on leading power factors
C. providing damper bars in the rotor pole faces
D. oscillations cannot be damped
A. maintaining constant excitation
B. running the motor on leading power factors
C. providing damper bars in the rotor pole faces
D. oscillations cannot be damped
A. d.c. series machines
B. d.c. shunt machines
C. d.c. compound machines
D. any of the above
A. back e.m.f.
B. armature current
C. power factor
D. torque angle
A. Eddy current losses in the conductors
B. Iron losses in the stator
C. Copper losses in the slot portion of the conductors
D. Windage losses
E. None of the above
A. voltage booster
B. phase advancer
C. noise generator
D. mechanical synchronizer
A. no change of power factor
B. lagging power factor with over-excitation
C. leading power factor with under-excitation
D. leading power factor with over-excitation
A. Windage loss
B. Copper losses
C. Any of the above
D. None of the above