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

Question 1 of 18

1. Which converter is having high efficiency?

Rotary converter

SCR converter

Mercury arc rectifier

Motor generator set

Question 1 of 18

Question 2 of 18

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

Reduce the losses in motor

Carry more load in motor

Improve the power factor

Run the motor at synchronous speed

Question 2 of 18

Question 3 of 18

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

Increasing the speed of motor

Varying the line voltage

Varying the field excitation

Decreasing the speed of motor

Question 3 of 18

Question 4 of 18

4. What is the name of the converter?

Metal rectifier

Silicon controlled rectifier

Mercury arc rectifier

Rotary converter

Question 4 of 18

Question 5 of 18

5. Which converting device can be over loaded?

Motor generator set

Rectifier unit

Rotary converter

Mercury arc rectifier

Question 5 of 18

Question 6 of 18

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

Converts AC to DC

Helps to deliver without noise

Collects the delivered direct current

Reduces voltage drop

Question 6 of 18

Question 7 of 18

7. What is the advantage of motor generator set?

High efficiency

Low maintenance required

Noiseless

DC output voltage can be easily controlled

Question 7 of 18

Question 8 of 18

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

Heavily doped device

Designed for light emitting

Very low power device

Very sensitive to temperature

Question 8 of 18

Question 9 of 18

9. Which acts as both inverter and converter?

Metal rectifier

Semi conductor diode

Synchronous converter

Mercury arc rectifier

Question 9 of 18

Question 10 of 18

10. 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 10 of 18

Question 11 of 18

11. What is the name of the converter?

Metal rectifier

Motor-Generator set

Mercury arc rectifier

Rotary converter

Question 11 of 18

Question 12 of 18

12. Which is the main application of synchronous motor?

Paper rolling mills

Power factor correction device

AC to DC converter

Elevators

Question 12 of 18

Question 13 of 18

13. Which application requires only DC?

Operating repulsion motor

Electroplating

Operating induction motor

Stepping up of voltage

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

Start the motor initially

Reduce the losses

Run the motor with over load

Question 14 of 18

Question 15 of 18

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

Varying stator current in motor

Varying stator voltage in motor

Varying the rotor excitation

Varying the motor load

Question 15 of 18

Question 16 of 18

16. 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 16 of 18

Question 17 of 18

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

Defective pony motor

Open in damper winding

Short in damper winding

Insufficient excitation

Question 17 of 18

Question 18 of 18

18. What is the function of inverter?

Convert pulsating DC into pure D.C

Convert D.C to A.C

Smoothening A.C sine wave

Convert A.C to D.C

Question 18 of 18