A. one-third
B. twice
C. thrice
D. six times
E. nine times
Related Mcqs:
- 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 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 - A synchronous motor is running with normal excitation. When the load is increased, the armature current drawn by it increases because
A. speed of the motor is reduced
B. power factor is decreased
C. Eb (back e.m.f.) becomes less than V (applied voltage)
D. Er (net resultant voltage) in armature is increased
E. none of the above - A synchronous motor connected to infinite bus-bars has at constant full load, 100% excitation and unity power factor. On changing the excitation only, the armature current will have_____________?
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 - If excitation of a synchronous motor running with a constant load is decreased from its normal value, ignoring effects of armature reaction, it leads to____________?
A. increase in both armature current and power factor angle
B. increase in back e.m.f. but decrease in armature current
C. increase in both armature current and power factor which is lagging
D. increase in torque angle but decrease in back e.m.f. - 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. - The effect of increasing the load on a synchronous motor running with normal excitation is to___________?
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 synchronous motor running with normal excitation adjusts to load increases essentially by increase in______________?
A. back e.m.f.
B. armature current
C. power factor
D. torque angle - The ratio of starting torque to running torque in a synchronous motor is____________?
A. zero
B. one
C. two
D. infinity
