Explore topic-wise MCQs in Dc Machines.

This section includes 4 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.

400-V dc shunt motor takes a current of 5.6 A on no-load and 68.3 A on full-load. Armature reaction weakens the field by 3%. What is the ratio of full-load speed to no-load speed? Given: Ra = 0.18 , brush voltage drop= 2 V, Rf = 200 .

A. 1.2
B. 0.8
C. 1.4
D. 1
Answer» E.
Discussion
2.

For speed x rpm, we get field current If1 and for speed y rpm, we get the field current If2. If y is greater than x then, ________________

A. I<sub>f1</sub> <i>f2
B. I<sub>f1</sub> &gt;I<sub>f2</sub>
C. I<sub>f1</sub> =I<sub>f2</sub>
D. Cannot comment on I<sub>f1</sub>, I<sub>f2</sub>
Answer» C. I<sub>f1</sub> =I<sub>f2</sub>
Discussion
3.

Working range of the speed-torque characteristic, with increasing speed will ___________

A. Reduce
B. Increase
C. Remain same
D. Cannot comment
Answer» B. Increase
Discussion
4.

Where will speed-torque characteristics will lie when armature reaction is considered?

A. Below the speed-torque characteristics when armature reaction is not considered
B. Above the speed-torque characteristics when armature reaction is not considered
C. On the speed-torque characteristics when armature reaction is not considered
D. Can be anywhere with the speed-torque characteristics when armature reaction is not considered
Answer» C. On the speed-torque characteristics when armature reaction is not considered
Discussion