A. when under loaded
B. while over-excited
C. only at synchronous speed
D. below or above synchronous speed
A synchronous motor can develop synchronous torque: Read More »
Synchronous Motors A. the rotor excitation only
B. the supply voltage only
C. the rotor excitation and supply volt-age both
D. the rotor excitation, supply voltage and maximum value of coupling angle (90°)
E. none of the above
The maximum power developed in a synchronous motor will depend on__________? Read More »
Synchronous Motors A. directly proportional to the square of the applied voltage
B. directly proportional to applied voltage
C. inversely proportional to applied voltage
D. none of the above
In a synchronous motor, the breakdown torque is__________? Read More »
Synchronous Motors A. static condenser
B. condenser
C. synchronous condenser
D. none of the above
A. the stator current will be zero
B. the stator current will be very small
C. the stator current will be very high
D. the back e.m.f. will be more than the supply voltage
E. none of the above
A. rotor and stator teeth
B. rotor and the stator poles of opposite polarity
C. rotor and the stator poles of the same polarity
D. none of the above
A. locked-rotor torque
B. synchronous torque
C. pull up torque
D. reluctance torque
A. stop
B. run as induction motor
C. function as static condenser
D. burn with dense smoke
A. lower stability limit
B. high stability limit
C. good speed regulation
D. good voltage regulation
E. none of the above
A synchronous machine with low value of short-circuit ratio has___________? Read More »
Synchronous Motors A. pull-up torque
B. pull-in torque
C. pull-out torque
D. none of the above
