Related Questions

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
The operating speed of a synchronous motor can be changed to new fixed value by
A changing the load
B changing the supply voltage
C changing frequency
D using brakes
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
When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop
A inductor motor torque
B induction generator torque
C synchronous motor torque
D d.c. motor toque
In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will
A Become unstable
B Draw excessive armature current and may burn out
C Fall out of synchronism and come to stand still
D Run as induction motor
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.
a motor -cycle covers 40 Km with a speed of 20 km /hr. Find the speed of the motor -cycle for the next 40 km journey so that the average speed of the whole journey will be 30 km / hr.
A 70.0km /hr
B 52.5km /hr
C 60.0km/hr
D 60. 5 km / hr
A motor cycle covers 40 km with a speed of 20 km/hr. Find the speed of the motor cycle for the next 40 km journy so that the average speed of the whole journey will be 30 km/hr?
A 70
B 52.5
C 60
D 60.5
In a synchronous motor running with fixed excitation, when the load is increased three times, its torque angle becomes approximately
A One-third
B Twice
C Thrice
D Six times

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