Electric Drives (3160919) MCQs

MCQs of DC motor characteristics

Showing 21 to 30 out of 71 Questions
21.

Belt conveyors offer

(a)

Zero starting torque

(b)

Low starting torque

(c)

Medium starting torque

(d)

High starting torque

Answer:

Option (d)

22.

Which type of Motor is best suited for the excavator?

(a)

DC Shunt Motor

(b)

Differential Motor

(c)

DC series Motor

(d)

Synchronous Motor

Answer:

Option (c)

23.

The DC shunt motor is running with a certain load. The effect of adding an external resistance in field circuit is to

(a)

Increase the Motor Speed

(b)

Stop the Motor

(c)

Reduce the motor Speed

(d)

Reduce the armature speed

Answer:

Option (a)

24.

The series field of long shunt compound generator is excited by

(a)

Supply current

(b)

Field current

(c)

Load current

(d)

Armature current

Answer:

Option (c)

25.

No-load speed of which of the following motor is highest?

(a)

Differentially compound motor

(b)

Cumulative compound motor

(c)

Series Motor

(d)

Shunt Motor

Answer:

Option (c)

26.

No-load speed of which of the following motor is highest?

(a)

Differentially compound motor

(b)

Cumulative compound motor

(c)

Series Motor

(d)

Shunt Motor

Answer:

Option (c)

27.

 Which DC motor has the least percentage increase in Input current for the same percentage increase in torque?

(a)

Separately excited motor

(b)

Series motor

(c)

Shunt motor

(d)

Compound motor

Answer:

Option (b)

28.

Counter EMF of the DC motor is

(a)

Less than the applied voltage

(b)

More than the applied voltage

(c)

Equal to the applied voltage

(d)

None of the above

Answer:

Option (a)

29.

Why is the speed of DC shunt motor dependent on Back EMF?

(a)

Because flux is proportional to the armature current

(b)

Because armature drop is negligible

(c)

Because Back EMF is equal to armature current

(d)

Because flux is constant in DC shunt motor

Answer:

Option (d)

30.

The reason for using starter while starting of DC motor is

(a)

To restrict armature current as there is no back E.M.F at starting

(b)

Motors are not self-starting

(c)

Restrict starting torque

(d)

None of the above

Answer:

Option (a)

Showing 21 to 30 out of 71 Questions