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
While testing a capacitor with ohm meter, if the capacitor shows charging, but the final resistance reading is appreciably less than normal, it can be concluded that the capacitor is
A Short-circuited
B Open circuited
C Alright
D Leaky
In a two value capacitor motor, the capacitor used for running purposes is
A air capacitor
B paper spaced oil filled type
C ceramic type
D a.c. electrolytic type
In a capacitor start single-phase motor, when capacitor is replaced by a resistance
A torque will increase
B the motor will consume less power
C motor will run in reverse direction
D motor will continue to run in same direction
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
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 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 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
If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will
A stop
B run as induction motor
C function as static condenser
D burn with dense smoke

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