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
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
When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor
A remains same as the original value
B decreases to half the original value
C tends to becomes zero
D increases to two times the original value
Multilayer helical windings are commonly used in the transformers as high voltage windings
A upto 20 kV
B upto 50 kV
C upto 80 kV
D for 110 kV and above
The insulation between windings and grounded core and the insulation between the windings of the same phase is
A minor insulation
B major insulation
C either of the above
D none of the above
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
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

Next steps