Question 1 of 18

1. What is the purpose of damper winding in a synchronous motor at starting?

Produces torque and runs near in synchronous speed

Produce high current to start rotate the motor

Produce high voltage to initiate the rotation

Produce a high magnetic-field to maintain a constant speed

Question 1 of 18

Question 2 of 18

2. Why the synchronous motor fails to run at synchronous speed?

Open in damper winding

Short in damper winding

Defective pony motor

Insufficient excitation

Question 2 of 18

Question 3 of 18

3. Why D.C supply is necessary for synchronous motor operation?

Run the motor at synchronous speed

Start the motor initially

Run the motor with over load

Reduce the losses

Question 3 of 18

Question 4 of 18

4. Which application requires only DC?

Operating repulsion motor

Electroplating

Stepping up of voltage

Operating induction motor

Question 4 of 18

Question 5 of 18

5. How synchronous motor works as a power factor corrector?

Varying the field excitation

Decreasing the speed of motor

Increasing the speed of motor

Varying the line voltage

Question 5 of 18

Question 6 of 18

6. Which is the main application of synchronous motor?

Power factor correction device

Paper rolling mills

AC to DC converter

Elevators

Question 6 of 18

Question 7 of 18

7. Which converting device can be over loaded?

Motor generator set

Rectifier unit

Rotary converter

Mercury arc rectifier

Question 7 of 18

Question 8 of 18

8. What is the name of the converter?

Mercury arc rectifier

Metal rectifier

Rotary converter

Motor-Generator set

Question 8 of 18

Question 9 of 18

9. Which converter is having high efficiency?

Motor generator set

Mercury arc rectifier

SCR converter

Rotary converter

Question 9 of 18

Question 10 of 18

10. Why the LED's are avoided as converters in rectifier diodes?

Very sensitive to temperature

Designed for light emitting

Heavily doped device

Very low power device

Question 10 of 18

Question 11 of 18

11. What is the function of the part marked as 'X' of the rotary converter?

Helps to deliver without noise

Collects the delivered direct current

Reduces voltage drop

Converts AC to DC

Question 11 of 18

Question 12 of 18

12. How the synchronous motor is used as a synchronous condenser?

Varying stator voltage in motor

Varying stator current in motor

Varying the motor load

Varying the rotor excitation

Question 12 of 18

Question 13 of 18

13. Which acts as both inverter and converter?

Semi conductor diode

Synchronous converter

Mercury arc rectifier

Metal rectifier

Question 13 of 18

Question 14 of 18

14. What is the function of inverter?

Convert A.C to D.C

Convert pulsating DC into pure D.C

Convert D.C to A.C

Smoothening A.C sine wave

Question 14 of 18

Question 15 of 18

15. What is the advantage of motor generator set?

Low maintenance required

Noiseless

High efficiency

DC output voltage can be easily controlled

Question 15 of 18

Question 16 of 18

16. What is the name of the converter?

Silicon controlled rectifier

Metal rectifier

Mercury arc rectifier

Rotary converter

Question 16 of 18

Question 17 of 18

17. Why exciter is essential to run a synchronous motor?

Improve the power factor

Carry more load in motor

Reduce the losses in motor

Run the motor at synchronous speed

Question 17 of 18

Question 18 of 18

18. What is the function of damper windings in synchronous motor?

Maintain constant speed

Excite the field winding

Maintain power factor

Start the synchronous motor

Question 18 of 18