Synchronous Motors

A. inductor motor torque
B. induction generator torque
C. synchronous motor torque
D. d.c. motor toque
E. none of the above

A. connected to D.C. supply
B. short-circuited by low resistance
C. kept open-circuited
D. none of the above

A. of reducing number of slip rings on the rotor
B. armature is associated with large power as compared to the field circuits
C. of difficulty of providing high voltage insulation on rotor
D. all of the above reasons

A. stator supply is relieved of responsibility of producing magnetic field
B. mechanical load on the motor can be adjusted
C. synchronous motor runs at synchronous speed
D. synchronous motor has large air gap

A. will refuse to start
B. will overheat in spots
C. will not come upto speed
D. will fail to pull into step

A. 10 per cent
B. 6 per cent
C. 4 per cent
D. 2. per cent
E. zero

A. rotor excitation
B. maximum value of coupling angle
C. direction of rotation
D. supply voltage

A. decrease both armature current and power factor
B. decrease armature current but increase power factor
C. increase armature current but decrease power factor
D. increase both its armature current and power factor

A. load on the motor
B. d.c. excitation only
C. both the speed and rotor flux
D. none of the above

A. windage friction
B. variable load
C. variable frequency
D. variable supply voltage