ELECTRICIAN 2nd YEAR MODULE – Synchronous Motor and MG Set ONLINE TEST

Question 1 of 18

1. What is the function of inverter?

Convert pulsating DC into pure D.C

Convert A.C to D.C

Convert D.C to A.C

Smoothening A.C sine wave

Question 1 of 18

Question 2 of 18

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

Run the motor at synchronous speed

Carry more load in motor

Improve the power factor

Reduce the losses in motor

Question 2 of 18

Question 3 of 18

3. 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 3 of 18

Question 4 of 18

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

Converts AC to DC

Helps to deliver without noise

Reduces voltage drop

Collects the delivered direct current

Question 4 of 18

Question 5 of 18

5. Which acts as both inverter and converter?

Semi conductor diode

Metal rectifier

Synchronous converter

Mercury arc rectifier

Question 5 of 18

Question 6 of 18

6. What is the name of the converter?

Silicon controlled rectifier

Rotary converter

Metal rectifier

Mercury arc rectifier

Question 6 of 18

Question 7 of 18

7. Which converting device can be over loaded?

Rotary converter

Motor generator set

Mercury arc rectifier

Rectifier unit

Question 7 of 18

Question 8 of 18

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

Start the synchronous motor

Maintain constant speed

Excite the field winding

Maintain power factor

Question 8 of 18

Question 9 of 18

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

Very sensitive to temperature

Designed for light emitting

Very low power device

Heavily doped device

Question 9 of 18

Question 10 of 18

10. What is the advantage of motor generator set?

DC output voltage can be easily controlled

Low maintenance required

Noiseless

High efficiency

Question 10 of 18

Question 11 of 18

11. Which application requires only DC?

Stepping up of voltage

Operating repulsion motor

Electroplating

Operating induction motor

Question 11 of 18

Question 12 of 18

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

Increasing the speed of motor

Varying the field excitation

Decreasing the speed of motor

Varying the line voltage

Question 12 of 18

Question 13 of 18

13. What is the name of the converter?

Mercury arc rectifier

Metal rectifier

Rotary converter

Motor-Generator set

Question 13 of 18

Question 14 of 18

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

Short in damper winding

Defective pony motor

Open in damper winding

Insufficient excitation

Question 14 of 18

Question 15 of 18

15. Which is the main application of synchronous motor?

Elevators

Paper rolling mills

AC to DC converter

Power factor correction device

Question 15 of 18

Question 16 of 18

16. Which converter is having high efficiency?

Rotary converter

Mercury arc rectifier

Motor generator set

SCR converter

Question 16 of 18

Question 17 of 18

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

Produce high voltage to initiate the rotation

Produce a high magnetic-field to maintain a constant speed

Produces torque and runs near in synchronous speed

Produce high current to start rotate the motor

Question 17 of 18

Question 18 of 18

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

Varying the rotor excitation

Varying the motor load

Varying stator voltage in motor

Varying stator current in motor

Question 18 of 18