Electrical Drives MCQ Multiple Choice Questions Answers | Quiz for Practice

Q: 1. To save energy during braking ................. braking is used?

Correct Answer is: regenerative

Q: 3. A four quadrant operation requires

Correct Answer is: two full converter connected in back to back

Q: 4. A motor has a thermal heating time constant of 50 mm. When the motor runs continuous of full scale, its final temperature rise is 80° C, what would be the temperature rise after 1 hour, if the motor runs continuously on full load?

Correct Answer is: 55.9 degrees

Q: 5. An elevator drive is required to operate in

Correct Answer is: four quadrants

Q: 6. Electric drive is becoming more and more popular because

Correct Answer is: All of the below

Q: 7. For an IM to operate in braking region slip should be always

Correct Answer is: greater than 1

Q: 8. Full form of VVVF control

Correct Answer is: variable voltage variable frequency

Q: 10. In 4 quadrant operation of a hoist 3rd quadrant represents

Correct Answer is: reverse motoring

Q: 11. In case of kiln drives, starting torque is

Correct Answer is: more than double of the running torque

Q: 12. In industries which electrical braking is preferred?

Correct Answer is: Regenerative braking

Welcome to our Electrical Drives MCQ Quiz Category! This section is designed to help students and exam aspirants test their knowledge and prepare effectively for exams and interviews.

About Electrical Drives MCQ Questions

Electrical Drives MCQs cover essential topics such as motor control, drive systems, and power electronics. These questions are crafted to deepen your understanding of how electrical motors and drives operate in various applications, from industrial to residential settings.

Why Practice Electrical Drives Objective Questions?

Practicing these objective questions offers numerous benefits. They help you reinforce your knowledge, identify weak areas, and prepare for both academic exams and professional interviews. Regular practice enhances your problem-solving skills and boosts your confidence.

Who Should Use These MCQs?

Students preparing for school or college exams
Competitive exam aspirants
Candidates preparing for interviews

Electrical Drives MCQ Questions for Practice

1. To save energy during braking ................. braking is used?

plugging
All of the above
regenerative
dynamic

2. A 3 - F induction motor draws an electric current of 50 A from mains when starts by direct switching. If an auto transformer with 60 % tapping is used for starting the electric current drawn from the mains will be

3. A four quadrant operation requires

two full converters connected in parallel
two semi converters connected in back to back
two full converter connected in back to back
two full converters in series

4. A motor has a thermal heating time constant of 50 mm. When the motor runs continuous of full scale, its final temperature rise is 80° C, what would be the temperature rise after 1 hour, if the motor runs continuously on full load?

58 degrees
60 degrees
56 degrees
55.9 degrees

5. An elevator drive is required to operate in

two quadrants
four quadrants
three quadrants
one quadrant only

6. Electric drive is becoming more and more popular because

it is cheaper in cost
All of the below
it is simple and reliable
it provide smooth and easy control

7. For an IM to operate in braking region slip should be always

greater than 1
None of these
is equal to 1
less than zero

8. Full form of VVVF control

VAr variable voltage frequency
variable voltage variable frequency
variable VAr voltage frequency
variable voltage VAr frequency

9. High braking torque produced in

dynamic braking
None of these
regenerative braking
plugging

10. In 4 quadrant operation of a hoist 3rd quadrant represents

reverse braking
forward motoring
forward braking
reverse motoring

11. In case of kiln drives, starting torque is

more than triple of the running torque
less than running torque
almost equal to running torque
more than double of the running torque

12. In industries which electrical braking is preferred?

Plugging
None of these
Dynamic braking
Regenerative braking

13. In which braking back emf exceeds supply voltage?

Dynamic
None of these
Plugging
Regenerative

14. Polarity of supply voltage is reversed in which type of braking?

Dynamic braking
None of these
Plugging
Regenerative braking.

15. Speed control by variation of field flux results in

constant torque drive
None of these
variable power drive
constant power drive

16. The basic elements of a electric drive are

control system
None of these
electrical motor and control system
electric motor

17. The concept of V/f control of inverters driving induction motors resuls in

speed reversal
hormonic elimination
reduced magnetic loss
constant torque operation

18. The heating time constant of an electrical machine gives an induction of its

cooling
short time rating
overload capacity
rating

19. The power input to a 3 - F induction motor is 60 kW and stator loss is 1 kW the rotor cu loss per phase is

slip Ã— 59 / 3
1
slip Ã— 69 / 3
slip Ã— 50 / 3

20. The slip of an induction motor during DC rheostatic braking is

1 - s
s
2 + s
2 - s

21. What are the constituents in speed time curve of train?

Initial acceleration
All of the above
Constant speed
Coasting

22. What type electric drive is used in cranes?

Group
Both A and C
Individual
Multimotor

23. Which braking is not possible in series motor?

Dynamic braking
Rheostat braking
Counter current braking
Regenerative braking

24. Which of the following are electrical braking methods ?

dynamic
All of the above
regenerative
plugging

25. Which speed control method preferred for constant torque drive?

Armature voltage control
None of these
Mechanical loading system
Field control

26. While operating on variable frequency supplies, the AC motor requires variable voltage in order to

avoid effect of saturation
protect thyristor from dV / dt
improve the capabilities of the inverter
protect the insulation