Electrical Drives Quiz

1. The specific energy consumption of a train depends on which of the following?

(a) Acceleration and retardation
(b) Gradient
(c) Distance covered
(d) All of the above

2. The friction at the track is proportional to

(a) 1/speed
(b) speed
(c) 1/speed²
(d) none of the above

3. The air resistance to the movement of the train is proportional to

(a) 1/speed
(b) speed
(c) speed²
(d) none of the above

4. The normal value of adhesion friction is

(a) 0.12
(b) 0.25
(c) 0.40
(d) 0.75

5. The resistance encountered by a train in motion is on account of

(a) resistance offered by air
(b) friction at the track
(c) friction at various parts of the rolling stock
(d) all of the above

6. …………. method can bring the locomotive to dead stop.

(a) Plugging braking
(b) Rheostatic braking
(c) Regenerative braking
(d) None of the above

7. The value of co-efficient of adhesion will be high when rails are

(a) greased
(b) wet
(c) sprayed with oil
(d) cleaned with sand

8. For three-phase induction motors which of the following is the least efficient method of speed control ?

(a) Cascade control
(b) Pole changing
(c) Rheostatic control
(d) Combination of cascade and pole changing

9. Specific energy consumption becomes

(a) more on steeper gradient
(b) more with high train resistance
(c) less if distance between stops is more
(d) all of the above

10. In main line service as compared to urban and suburban service

(a) distance between the stops is more
(b) maximum speed reached is high
(c) acceleration and retardation rates are low
(d) all of the above

11. Locomotive having monomotor bogies

(a) has better co-efficient of adhesion
(b) are suited both for passenger as well as freight service
(c) has better riding qualities due to the reduction of lateral forces
(d) has all above qualities

12. Energy consumption in propelling the train is required for which of the following

(a) Work against the resistance to motion
(b) Work against gravity while moving up the gradient
(c) Acceleration
(d) All of the above

13. An ideal traction system should have

(a) easy speed control
(b) high starting tractive effort
(c) equipment capable of withstanding large temporary loads
(d) all of the above

14 …………have maximum unbalanced forces.

(a) Diesel shunters
(b) Steam locomotives
(c) Electric locomotives
(d) Diesel locomotives

15. Specific energy consumption is affected by which of the following factors ?

(a) Retardation and acceleration values
(b) Gradient
(c) Distance between stops
(d) All of the above

16. In case of ………………free running and coasting periods are generally long.

(a) main-line service
(b) urban service
(c) sub-urban service
(d) all of the above

17. Specific energy consumption is least in ………….. service.

(a) main line
(b) urban
(c) suburban

18. Locomotives with monomotor bogies have

(a) uneven distribution of tractive effect
(b) suitability for passenger as well as freight service
(c) lot of skidding
(d) low co-efficient of adhesion

19. …………..was the first city in India to adopt electric traction.

(a) Delhi
(b) Madras
(c) Calcutta
(d) Bombay

20. Power for lighting in passenger coach, in a long distance electric train, is provided

(a) directly through overhead electric line
(b) through individual generator of bogie and batteries
(c) through rails
(d) through locomotive

21. Which of the following happens in Kando system?

(a) Three phase AC. is converted into D.C.
(b) Single phase AC. is converted into D.C.
(c) Single phase supply is converted into three phase system
(d) None of the above

22. For which of the following locomotives the maintenance requirements are the least ?

(a) Steam locomotives
(b) Diesel locomotives
(c) Electric locomotives
(d) Equal in all of the above

23. Which of the following methods is used to control speed of 25 kV, 50 Hz single phase traction ?

(a) Reduced current method
(b) Tap changing control of transformer
(c) Series parallel operation of motors
(d) All of the above

24. If the co-efficient of adhesion on dry rails is 0.26, which of the following could be the value for wet rails?

(a) 0.3
(b) 0.26
(c) 0.225
(d) 0.16

25. The braking retardation is usually in the range of

(a) 0 .30 to 0.6 km phps
(b) 0.8 to 2.4 km phps
(c) 3 to 5 km phps
(d) 10 to 15 km phps

26. The rate of acceleration on suburban or urban service is in the range

(a) 0.2 to 0.6 km phps
(b) 1.6 to 4.0 km phps
(c) 5 to 10 km phps
(d) 15 to 26 km phps

27. The coasting retardation is around

(a) 0.16 km phps
(b) 1.6 km phps
(c) 16 km phps
(d) 40 km phps

28. ……………is the method of braking in which motor armature remains connected to the supply and draws power from it producing torque opposite to the direction of motion.

(a) Rheostatic braking
(b) Regerative braking
(c) Plugging

29. Besides a constant speed a synchronous motor possesses which of the following advantages?

(a) Lower cost
(b) Better efficiency
(c) High power factor
(d) All of the above

 

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