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 coupling angle or load angle of synchronous motor is defined as the angle between the
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
The maximum power developed in a synchronous motor occurs at a coupling angle of
A 30°
B 60°
C 90°
D 180°
A synchronous motor develops maximum power when load angle is
A 45°
B 60°
C 90°
D 120°
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
In a synchronous motor, the maximum power developed depends on all of the following except
A rotor excitation
B maximum value of coupling angle
C direction of rotation
D supply voltage
The maximum power developed in a synchronous motor will depend on
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°)
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.
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
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

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