Electrical Drives MCQ Quiz - Multiple Choice Questions & Answers Page 2

11. In case of kiln drives, starting torque is

1. almost equal to running torque
2. more than double of the running torque
3. more than triple of the running torque
4. less than running torque

12. In industries which electrical braking is preferred?

1. Dynamic braking
2. Regenerative braking
3. Plugging
4. None of these

13. In which braking back emf exceeds supply voltage?

1. Plugging
2. Regenerative
3. Dynamic
4. None of these

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

1. Plugging
2. Regenerative braking.
3. Dynamic braking
4. None of these

15. Speed control by variation of field flux results in

1. variable power drive
2. constant power drive
3. constant torque drive
4. None of these

16. The basic elements of a electric drive are

1. electrical motor and control system
2. electric motor
3. control system
4. None of these

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

1. reduced magnetic loss
2. constant torque operation
3. speed reversal
4. hormonic elimination

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

1. overload capacity
2. rating
3. cooling
4. short time 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

1. slip × 69 / 3
2. slip × 50 / 3
3. slip × 59 / 3
4. 1

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

1. 2 + s
2. 2 - s
3. 1 - s
4. s