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
A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is
A Slop speed operation
B High starting torque
C Low windage losses
D All of the above
A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because
A synchronous motor has no slip
B stator supply is not required to produce magnetic field
C mechanical load on the rotor remains constant
D synchronous motor has large airgap
The power factor of a synchronous motor is better than that of induction motor because
A stator supply is relieved of responsibility of producing magnetic field
B mechanical load on the motor can be adjusted
C synchronous motor runs at synchronous speed
D synchronous motor has large air gap
While starting a synchronous motor by induction motor action, field winding is usually
A connected to D.C. supply
B short-circuited by low resistance
C kept open-circuited
D none of the above
The power factor of an induction motor under no-load conditions will be closer to
A 0.2 lagging
B 0.2 leading
C 0.5 leading
D unity
The low power factor of induction motor is due to
A Rotor leakage reactance
B Stator reactance
C The reactive lagging magnetizing current necessary to generate the magnetic flux
D All of the above
The good power factor of an induction motor can be achieved if the average flux density in the air gap is
A Absent
B Small
C Large
D Infinity
An induction motor has relatively high power factor at
A rated r.p.m.
B no load
C 20 percent load
D near full load
E 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.

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