Explore topic-wise MCQs in Dc Machines.

This section includes 21 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.

Retardation curve is ______________

A. Starting from origin
B. Starts from some positive value and increasing
C. Starts from some positive curve and stays constant
D. Starts from some positive value and decreases
Answer» E.
Discussion
2.

In retardation test _____________

A. Motor switch is made ON and various speed readings are taken
B. At rated speed various speed readings are taken out at different times
C. Motor switch is made OFF at rated speed and various speed readings are taken
D. Some readings are taken while speed is building up and some readings while speed is lowering down
Answer» D. Some readings are taken while speed is building up and some readings while speed is lowering down
Discussion
3.

While carrying out retardation test, if t is equal to time constant then _____________

A. Speed increases to 36.8% of its initial value
B. Speed reduces to 36.8% of its initial value
C. Speed reduces to 26.8% of its initial value
D. Speed reduces to 46.8% of its initial value
Answer» C. Speed reduces to 26.8% of its initial value
Discussion
4.

Which of the following is not a disadvantage of a Swinburne’s test?

A. The stray-load losses can’t be determined by this test
B. Steady temperature rise can’t be determined
C. Does not give results about satisfactory commutation
D. Machine gets damaged
Answer» E.
Discussion
5.

Efficiency calculated by Swinburne’s test is _____________

A. Exactly equal
B. Over-estimated
C. Under-estimated
D. Depends on the manual errors
Answer» C. Under-estimated
Discussion
6.

What is the purpose of performing retardation test after Swinburne’s test?

A. To find stray load loss
B. To find variable losses
C. To separate out windage and friction losses
D. To find shunt field losses
Answer» D. To find shunt field losses
Discussion
7.

In order to run motor on rated speed while carrying out Swinburne’s test we add ______________

A. Resistance in parallel with armature
B. Resistance in series with armature
C. Inductor in series with armature
D. Capacitor in parallel with armature
Answer» C. Inductor in series with armature
Discussion
8.

While carrying out Swinburne’s test at rated armature voltage motor will run at ____________

A. Speed equal to rated speed
B. Speed greater than rated speed
C. Speed less than rated speed
D. Can run anywhere
Answer» C. Speed less than rated speed
Discussion
9.

Which losses can be identified from Swinburne’s test?

A. No-load core loss
B. Windage and friction loss
C. No-load and windage and friction loss
D. Stray load loss
Answer» D. Stray load loss
Discussion
10.

Swinburne’s test can be carried out on all DC motors.

A. True
B. FalseView Answer
Answer» C.
Discussion
11.

IN_RETARDATION_TEST______________?$

A. Motor switch is made ON and various speed readings are taken
B. At rated speed various speed readings are taken out at different times
C. Motor switch is made OFF at rated speed and various speed readings are taken
D. Some readings are taken while speed is building up and some readings while speed is lowering down
Answer» D. Some readings are taken while speed is building up and some readings while speed is lowering down
Discussion
12.

Retardation curve is ______________$

A. Starting from origin
B. Starts from some positive value and increasing
C. Starts from some positive curve and stays constant
D. Starts from some positive value and decreases
Answer» E.
Discussion
13.

While carrying out retardation test, if t is equal to time constant then ____________?

A. Speed increases to 36.8% of its initial value
B. Speed reduces to 36.8% of its initial value
C. Speed reduces to 26.8% of its initial value
D. Speed reduces to 46.8% of its initial value
Answer» C. Speed reduces to 26.8% of its initial value
Discussion
14.

Which of the following is not a disadvantage of a Swinburne’s test?#

A. The stray-load losses can’t be determined by this test
B. Steady temperature rise can’t be determined
C. Does not give results about satisfactory commutation
D. Machine gets damaged
Answer» E.
Discussion
15.

Efficiency calculated by Swinburne’s test is _____________$

A. Exactly equal
B. Over-estimated
C. Under-estimated
D. Depends on the manual errors
Answer» C. Under-estimated
Discussion
16.

What is the purpose of performing retardation test after Swinburne’s test?$

A. To find stray load loss
B. To find variable losses
C. To separate out windage and friction losses
D. To find shunt field losses
Answer» D. To find shunt field losses
Discussion
17.

In order to run motor on rated speed while carrying out Swinburne’s test we add ______________$

A. Resistance in parallel with armature
B. Resistance in series with armature
C. Inductor in series with armature
D. Capacitor in parallel with armature
Answer» C. Inductor in series with armature
Discussion
18.

While carrying out Swinburne’s test at rated armature voltage motor will run at ____________$

A. Speed equal to rated speed
B. Speed greater than rated speed
C. Speed less than rated speed
D. Can run anywhere
Answer» C. Speed less than rated speed
Discussion
19.

Which losses can be identified from Swinburne’s test?$

A. No-load core loss
B. Windage and friction loss
C. No-load and windage and friction loss
D. Stray load loss
Answer» D. Stray load loss
Discussion
20.

Which of the following test will be suitable for testing two similar DC series motors of large capacity?

A. Swinburne’s test
B. Hopkinson’s test
C. Field test
D. Brake test
Answer» D. Brake test
Discussion
21.

Swinburne’s test can be carried out on all DC motors.

A. True
B. False
Answer» C.
Discussion