Related Questions

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
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
In a capacitor start motor, the phase displacement between starting and running winding can be nearly
A 10°
B 30°
C 60°
D 90°
After the starting winding of a single phase induction motor is disconnected from supply, it continues to run only on
A running winding
B rotor winding
C field winding
D compensating winding
Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a
A Magnetic relay
B Thermal relay
C Centrifugal switch
D None of the above
A centrifugal switch is used to disconnect starting winding when motor has
A run for about 1 minute
B run for about 5 minutes
C picked up about 50 to 70 per cent of rated speed
D picked up about 10 to 25 per cent of rated speed
If starting winding of a single-phase induction motor is left in the circuit, it will
A run faster
B spark at light loads
C draw excessive current and overheat
D run slower
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
Some wire- wound resistors have bifilar winding. This type of winding is used to
A Increase the thermal stability
B Reduce the tolerance
C Reduce the inductance of winding
D Double the power rating of the resistor
________ cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall
A Direct
B Indirect
C Conventional
D Any of the above

Next steps