ELECTRICIAN 2nd YEAR MODULE – Synchronous Motor and MG Set

Question 1 of 18

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

Run the motor with over load

Run the motor at synchronous speed

Reduce the losses

Start the motor initially

Question 1 of 18

Question 2 of 18

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

Maintain constant speed

Maintain power factor

Excite the field winding

Start the synchronous motor

Question 2 of 18

Question 3 of 18

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

Varying the rotor excitation

Varying stator current in motor

Varying stator voltage in motor

Varying the motor load

Question 3 of 18

Question 4 of 18

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

Designed for light emitting

Very sensitive to temperature

Heavily doped device

Very low power device

Question 4 of 18

Question 5 of 18

5. Which converting device can be over loaded?

Motor generator set

Mercury arc rectifier

Rectifier unit

Rotary converter

Question 5 of 18

Question 6 of 18

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

Decreasing the speed of motor

Varying the line voltage

Increasing the speed of motor

Varying the field excitation

Question 6 of 18

Question 7 of 18

7. What is the name of the converter?

Silicon controlled rectifier

Metal rectifier

Rotary converter

Mercury arc rectifier

Question 7 of 18

Question 8 of 18

8. What is the advantage of motor generator set?

DC output voltage can be easily controlled

High efficiency

Low maintenance required

Noiseless

Question 8 of 18

Question 9 of 18

9. Which converter is having high efficiency?

Mercury arc rectifier

SCR converter

Rotary converter

Motor generator set

Question 9 of 18

Question 10 of 18

10. Which acts as both inverter and converter?

Mercury arc rectifier

Metal rectifier

Semi conductor diode

Synchronous converter

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

Converts AC to DC

Reduces voltage drop

Collects the delivered direct current

Question 11 of 18

Question 12 of 18

12. Which application requires only DC?

Electroplating

Operating induction motor

Operating repulsion motor

Stepping up of voltage

Question 12 of 18

Question 13 of 18

13. What is the name of the converter?

Rotary converter

Metal rectifier

Mercury arc rectifier

Motor-Generator set

Question 13 of 18

Question 14 of 18

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

Open in damper winding

Defective pony motor

Insufficient excitation

Short in damper winding

Question 14 of 18

Question 15 of 18

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

Run the motor at synchronous speed

Improve the power factor

Carry more load in motor

Reduce the losses in motor

Question 15 of 18

Question 16 of 18

16. Which is the main application of synchronous motor?

Elevators

AC to DC converter

Paper rolling mills

Power factor correction device

Question 16 of 18

Question 17 of 18

17. What is the function of inverter?

Convert A.C to D.C

Smoothening A.C sine wave

Convert pulsating DC into pure D.C

Convert D.C to A.C

Question 17 of 18

Question 18 of 18

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

Produce a high magnetic-field to maintain a constant speed

Produce high current to start rotate the motor

Produce high voltage to initiate the rotation

Produces torque and runs near in synchronous speed

Question 18 of 18