Synchronous Motors

A. the motor is said to be fully loaded
B. the torque generated is maximum
C. the excitation is said to be zero per cent
D. the excitation is said to be hundred per cent

A. 3000 r.p.m.
B. 1500 r.p.m.
C. 750 r.p.m.
D. none of the above

A. armature current and field current
B. power factor and speed
C. field current and speed
D. field current and power factor

A. By changing the supply frequency
B. By interchanging any two phases
C. By changing the applied voltage
D. By changing the load

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

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
E. none of the above

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. stator frame
B. rotor shaft
C. pole faces
D. none of the above

A. supplied with unbalanced voltage
B. under-loaded
C. over-loaded
D. none of the above

A. High field current
B. Low short circuit ratio
C. High core losses
D. Low field current