Related Questions

In an induction motor if air-gap is increased
A The power factor will be low
B Windage losses will be more
C Bearing friction will reduce
D Copper loss will reduce in an induction motor
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
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
Two-value capacitor motor finds increased application as compressor motor in small home air-conditioners because
A it is comparatively cheaper
B it has almost non-destructible capacitor
C it has low starting as well as running currents at relatively high power factor
D it is quiet in operation
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
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
While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by
A induction motor torque in field winding
B induction motor torque in damper winding
C eddy current and hysteresis torque in pole faces
D reHetance motor torque due to saliency of the rotor
E all of the above methods
Slip ring motor is preferred over squirrel cage induction motor where
A High starting torque is required
B Load torque is heavy
C Heavy pull out torque is required
D All of the above
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
An important advantage of a synchronous motor over wound round induction motor is that
A its power factor may be varied at will
B its speed is independent of supply frequency
C its speed may be controlled more easily
D none of the above

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