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.

If higher terminal voltage is applied to PMDC what will happen?

A. Speed at 0 torque will be reduced
B. Torque at 0 speed will be reduced
C. Torque at 0 speed will be increased
D. Torque will remain constant
Answer» D. Torque will remain constant
Discussion
2.

PMDC gives better speed regulation than DC shunt motor.

A. True
B. False
Answer» B. False
Discussion
3.

PMDC produces high torque on ______________

A. At low speeds
B. Only at maximum speed
C. Torque is constant
D. Cannot say
Answer» B. Only at maximum speed
Discussion
4.

Speed-torque characteristic of PMDC motors is _______________

A. Starting from zero increasing continuously
B. Starting from some positive value and remaining constant
C. Starting from some positive value and decreasing exponentially
D. Starting from some positive value and decreasing on straight line
Answer» E.
Discussion
5.

How the burnt winding is easy to recognize before dismantling the motor?

A. Smell
B. Color
C. Touching
D. Appearance
Answer» B. Color
Discussion
6.

PMDC_GIVES_BETTER_SPEED_REGULATION_THAN_DC_SHUNT_MOTOR.?$

A. True
B. False
Answer» B. False
Discussion
7.

PMDC_PRODUCES_HIGH_TORQUE_ON_______________?$

A. At low speeds
B. Only at maximum speed
C. Torque is constant
D. Cannot say
Answer» B. Only at maximum speed
Discussion
8.

If higher terminal voltage is applied to PMDC what will happen?$

A. Speed at 0 torque will be reduced
B. Torque at 0 speed will be reduced
C. Torque at 0 speed will be increased
D. Torque will remain constant
Answer» D. Torque will remain constant
Discussion
9.

Speed-torque characteristic of PMDC motors is ______________?

A. Starting from zero increasing continuously
B. Starting from some positive value and remaining constant
C. Starting from some positive value and decreasing exponentially
D. Starting from some positive value and decreasing on straight line
Answer» E.
Discussion
10.

Which of the following is most favoured choice for PMDC motor?

A. Neodymium-iron-boron
B. Iron-nickel
C. Nickel-neodymium
D. Cannot be given
Answer» B. Iron-nickel
Discussion
11.

What is the air gap flux density for PMDC motor?

A. B<sub>g</sub>= µ<sub>0</sub>(t<sub>m</sub>/l<sub>g</sub>) H<sub>m</sub>
B. B<sub>g</sub>= – µ<sub>0</sub>H<sub>m</sub>
C. B<sub>g</sub>= – µ<sub>0</sub>(t<sub>m</sub>/l<sub>g</sub>) H<sub>m</sub>
D. B<sub>g</sub>= – µ<sub>0</sub>(lg/t<sub>m</sub>) H<sub>m</sub>
Answer» D. B<sub>g</sub>= ‚Äö√Ñ√∂‚àö√ë‚àö¬® ¬¨¬®¬¨¬µ<sub>0</sub>(lg/t<sub>m</sub>) H<sub>m</sub>
Discussion
12.

Which speed control method is employed in PMDC?

A. Field control method
B. Armature control method
C. Armature Field control method
D. Cannot be determined
Answer» C. Armature Field control method
Discussion
13.

PMDC motor offers ___________

A. Cumulative compound type characteristic
B. Differential compound type characteristic
C. Series characteristic
D. Shunt characteristic
Answer» E.
Discussion
14.

PMDC motors are _________________

A. Smaller than corresponding rated field wound motor
B. Larger than corresponding rated field wound motor
C. Almost same size that of corresponding rated field wound motor
D. Can be smaller or greater than corresponding rated field wound motor
Answer» B. Larger than corresponding rated field wound motor
Discussion
15.

In PMDC magnetic material is placed instead of _____________

A. Armature
B. Rotor
C. Stator
D. Can be placed anywhere
Answer» D. Can be placed anywhere
Discussion
16.

In PMDC motors we use magnetic material with ___________

A. Low residual flux
B. Low coercivity
C. High residual flux
D. All magnetic materials
Answer» D. All magnetic materials
Discussion