ELECTRICIAN 2nd YEAR MODULE – Synchronous Motor and MG Set

Question 1 of 18

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

Varying stator current in motor

Varying stator voltage in motor

Varying the motor load

Varying the rotor excitation

Question 1 of 18

Question 2 of 18

2. What is the name of the converter?

Metal rectifier

Silicon controlled rectifier

Rotary converter

Mercury arc rectifier

Question 2 of 18

Question 3 of 18

3. Which is the main application of synchronous motor?

AC to DC converter

Elevators

Power factor correction device

Paper rolling mills

Question 3 of 18

Question 4 of 18

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

Insufficient excitation

Defective pony motor

Short in damper winding

Open in damper winding

Question 4 of 18

Question 5 of 18

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

Maintain power factor

Start the synchronous motor

Excite the field winding

Maintain constant speed

Question 5 of 18

Question 6 of 18

6. Which converter is having high efficiency?

Mercury arc rectifier

SCR converter

Motor generator set

Rotary converter

Question 6 of 18

Question 7 of 18

7. 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 a high magnetic-field to maintain a constant speed

Produce high voltage to initiate the rotation

Question 7 of 18

Question 8 of 18

8. What is the function of inverter?

Smoothening A.C sine wave

Convert pulsating DC into pure D.C

Convert D.C to A.C

Convert A.C to D.C

Question 8 of 18

Question 9 of 18

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

Improve the power factor

Run the motor at synchronous speed

Carry more load in motor

Reduce the losses in motor

Question 9 of 18

Question 10 of 18

10. What is the name of the converter?

Rotary converter

Motor-Generator set

Mercury arc rectifier

Metal rectifier

Question 10 of 18

Question 11 of 18

11. What is the advantage of motor generator set?

Noiseless

High efficiency

Low maintenance required

DC output voltage can be easily controlled

Question 11 of 18

Question 12 of 18

12. Which converting device can be over loaded?

Rectifier unit

Rotary converter

Mercury arc rectifier

Motor generator set

Question 12 of 18

Question 13 of 18

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

Collects the delivered direct current

Converts AC to DC

Helps to deliver without noise

Reduces voltage drop

Question 13 of 18

Question 14 of 18

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

Run the motor at synchronous speed

Run the motor with over load

Reduce the losses

Start the motor initially

Question 14 of 18

Question 15 of 18

15. Which application requires only DC?

Electroplating

Operating induction motor

Operating repulsion motor

Stepping up of voltage

Question 15 of 18

Question 16 of 18

16. Which acts as both inverter and converter?

Mercury arc rectifier

Synchronous converter

Semi conductor diode

Metal rectifier

Question 16 of 18

Question 17 of 18

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

Varying the field excitation

Increasing the speed of motor

Varying the line voltage

Decreasing the speed of motor

Question 17 of 18

Question 18 of 18

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

Very sensitive to temperature

Very low power device

Heavily doped device

Designed for light emitting

Question 18 of 18