D.C. Motors

11. D.C. generators are installed near the load centres to reduce

1. iron losses
2. line losses
3. sparking
4. corona losses

View answer

12. D.C. generators are normally designed for maximum efficiency around

1. full-load
2. rated r.p.m.
3. rated voltage
4. all of the above

View answer

13. D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select this

1. series motor
2. shunt motor
3. compound motor
4. any of the above

View answer

14. D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the

1. series motor
2. shunt motor
3. compound motor
4. any of the above

View answer

15. D.C. series motors are used

1. where load is constant
2. where load changes frequently
3. where constant operating speed is needed
4. in none of the above situations.

View answer

16. D.C. shunt motors are used for driving

1. trains
2. cranes
3. hoists
4. machine tools

View answer

17. Differentially compound D.C. motors can find applications requiring

1. high starting torque
2. low starting torque
3. variable speed
4. frequent on-off cycles

View answer

18. During rheostat braking of D.C. series motors

1. motor is run as a generator
2. motor is reversed in direction
3. motor is run at reduced speed
4. none

View answer

19. Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be

1. level compounded
2. under compounded
3. cumulatively compounded
4. differentially compounded

View answer

20. Following motor is used where high starting torque and wide speed range control is required.

1. Single phase capacitor start
2. Induction motor
3. Synchronous motor
4. D.C. motor

View answer