Efficiency and Testing MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on Efficiency and Testing, a fundamental topic in the field of DC Machines. Whether you're preparing for competitive exams, honing your problem-solving skills, or simply looking to enhance your abilities in this field, our Efficiency and Testing MCQs are designed to help you grasp the core concepts and excel in solving problems.

In this section, you'll find a wide range of Efficiency and Testing mcq questions that explore various aspects of Efficiency and Testing problems. Each MCQ is crafted to challenge your understanding of Efficiency and Testing principles, enabling you to refine your problem-solving techniques. Whether you're a student aiming to ace DC Machines tests, a job seeker preparing for interviews, or someone simply interested in sharpening their skills, our Efficiency and Testing MCQs are your pathway to success in mastering this essential DC Machines topic.

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Efficiency and Testing MCQs | Page 3 of 4

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Q21.
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

Discuss
Answer: (c).No-load and windage and friction loss
Q22.
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

Discuss
Answer: (b).Speed greater than rated speed
Q23.
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

Discuss
Answer: (b).Resistance in series with armature
Q24.
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

Discuss
Answer: (c).To separate out windage and friction losses
Q25.
Efficiency calculated by Swinburne’s test is _____________

a.

Exactly equal

b.

Over-estimated

c.

Under-estimated

d.

Depends on the manual errors

Discuss
Answer: (b).Over-estimated
Q26.
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

Discuss
Answer: (d).Machine gets damaged
Q27.
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

Discuss
Answer: (b).Speed reduces to 36.8% of its initial value
Q28.
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

Discuss
Answer: (c).Motor switch is made OFF at rated speed and various speed readings are taken
Q29.
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

Discuss
Answer: (d).Starts from some positive value and decreases
Q30.
Hopkinson’s test of D.C. machines is conducted at _______________

a.

No-load

b.

Part load

c.

Full-load

d.

Overload

Discuss
Answer: (c).Full-load
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