Explore topic-wise MCQs in Dc Machines.

This section includes 16 Mcqs, each offering curated multiple-choice questions to sharpen your Dc Machines knowledge and support exam preparation. Choose a topic below to get started.

1.

How total number of brushes in a commutator are determined in a given DC machine?

A. Speed of armature
B. Type of winding
C. Voltage
D. Amount of current to be collected
Answer» E.
Discussion
2.

In case of DC machine winding, number of commutator segments is equal to ______

A. Number of armature coils
B. Number of armature coil sides
C. Number of armature conductors
D. Number of armature turns
Answer» B. Number of armature coil sides
Discussion
3.

Which conductors are in point of contact with brushes?

A. Lie under south pole
B. Lie under north pole
C. Lie in inter polar region
D. Are farthest from the poles
Answer» D. Are farthest from the poles
Discussion
4.

What are the number of the brushes in the wave winding?

A. Same or more than the number of poles
B. Same or less than the number of poles
C. Exactly half the number of poles
D. Depends on other parameters
Answer» B. Same or less than the number of poles
Discussion
5.

In DC generators, current is fed up to the external circuit from armature through _______

A. Commutator
B. Direct wire
C. Slip rings
D. Cannot be determined
Answer» B. Direct wire
Discussion
6.

WHICH_CONDUCTORS_ARE_IN_POINT_OF_CONTACT_WITH_BRUSHES??$

A. Lie under south pole
B. Lie under north pole
C. Lie in inter polar region
D. Are farthest from the poles
Answer» D. Are farthest from the poles
Discussion
7.

How total number of brushes in a commutator are determined in a given DC machine?$

A. Speed of armature
B. Type of winding
C. Voltage
D. Amount of current to be collected
Answer» E.
Discussion
8.

In case of DC machine winding, number of commutator segments is equal to ______$

A. Number of armature coils
B. Number of armature coil sides
C. Number of armature conductors
D. Number of armature turns
Answer» B. Number of armature coil sides
Discussion
9.

In DC generators, current is fed up to the external circuit from armature through ______?

A. Commutator
B. Direct wire
C. Slip rings
D. Cannot be determined
Answer» B. Direct wire
Discussion
10.

When Copper brushes are used in DC machine?

A. Where low voltage and high currents are involved
B. Where high voltage and small currents are involved
C. Cannot be determined
D. Where low voltage and low currents are involved
Answer» B. Where high voltage and small currents are involved
Discussion
11.

What are the number of the brushes in the lap winding?

A. Double the number of poles
B. Same as the number of poles
C. Half the number of poles
D. Two
Answer» C. Half the number of poles
Discussion
12.

In D.C. generators, rapid brush ware causes due to _________

A. Severe sparking
B. Rough commutator surface
C. Imperfect contact
D. Severe sparking, rough commutator surface or imperfect contact
Answer» E.
Discussion
13.

Which of the following method is used to connect commutator segments to armature conductors?

A. Brazing
B. Normal wires
C. Insulation pads
D. Copper lugs
Answer» E.
Discussion
14.

Commutator performs rectification so that output of the machine is bi-directional.

A. True
B. False
Answer» C.
Discussion
15.

In a DC machine, rectification provided with commutator is ___________

A. Half wave rectification
B. Full wave rectification
C. Semi controlled rectification
D. Uncontrolled rectification
Answer» C. Semi controlled rectification
Discussion
16.

The armature in DC machines is always placed on rotor because _______

A. Otherwise commutation will not be possible
B. Otherwise there will not be any induced emf
C. Otherwise current will not flow
D. Can be placed anywhere
Answer» B. Otherwise there will not be any induced emf
Discussion