A. Stator flux
B. Pull in torque
C. Both A. and (b)
D. None of the above
Related Mcqs:
- A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will___________?
A. remain same
B. go down
C. improve
D. none of the above - When V is the applied voltage, then the breakdown torque of a synchronous motor varies as_________?
A. V
B. V312
C. V2
D. 1/V - In a synchronous motor it the back e.m.f. generated in the armature at noload is approximately equal to the applied voltage, then
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 - As the load is applied to a synchronous motor, the motor takes more armature current because
A. the increased load has to take more current
B. the rotor by shifting its phase backward causes motor to take more current
C. the back e.m.f. decreases causing an increase in motor current
D. the rotor strengthens the rotating field casuing more motor current - If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor__________?
A. become more
B. become less
C. remain constant
D. none of the above - If in a synchronous motor, driving a given mechanical load and drawing current at a leading power factor from constant voltage supply its field excitation is increased, its power factor
A. will become more
B. will become less
C. will remain unchanged
D. none of the above. - A synchronous motor is running on a load with normal excitation. Now if the load on the motor is increased
A. power factor as well as armature current will decrease
B. power factor as well as armature current will increase
C. power factor will increase but armature current will decrease
D. power factor will decrease and armature current will increase - A synchronous motor can be used as a synchronous capacitor when it is____________?
A. under-loaded
B. over-loaded
C. under-excited
D. over-excited - A synchronous motor can develop synchronous torque:
A. when under loaded
B. while over-excited
C. only at synchronous speed
D. below or above synchronous speed - The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as__________?
A. locked-rotor torque
B. synchronous torque
C. pull up torque
D. reluctance torque
