DC Motors MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on DC Motors, 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 DC Motors 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 DC Motors mcq questions that explore various aspects of DC Motors problems. Each MCQ is crafted to challenge your understanding of DC Motors 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 DC Motors MCQs are your pathway to success in mastering this essential DC Machines topic.

Note: Each of the following question comes with multiple answer choices. Select the most appropriate option and test your understanding of DC Motors. You can click on an option to test your knowledge before viewing the solution for a MCQ. Happy learning!

So, are you ready to put your DC Motors knowledge to the test? Let's get started with our carefully curated MCQs!

DC Motors MCQs | Page 5 of 13

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Q41.
In three-point starter, as a starting handle is rotated __________

a.

The resistance is added into armature circuit

b.

The resistance is removed from field circuit

c.

The resistance is added into field circuit

d.

Resistance is neither added nor removed

Discuss
Answer: (c).The resistance is added into field circuit
Q42.
How much torque is ensured by resistance adding arrangement in 3-point starter?

a.

Low and non-zero

b.

Infinite

c.

High finite

d.

Zero

Discuss
Answer: (c).High finite
Q43.
The resistance of NVC is _______

a.

Small

b.

Large

c.

Infinite

d.

Zero

Discuss
Answer: (a).Small
Q44.
NVC will release the handle electromagnetically when ________

a.

In the case of failure of field current

b.

If the resistance is very high

c.

At the end of each rotation

d.

At the start of each rotation

Discuss
Answer: (a).In the case of failure of field current
Q45.
Over-load coil performs the function when __________

a.

In the case of failure of field current

b.

If the resistance is very high

c.

If armature current increases beyond certain value

d.

At the start of each rotation

Discuss
Answer: (c).If armature current increases beyond certain value
Q46.
In 4-point starters the resistance is added in series with NVC because __________________

a.

To increase field current

b.

To increase armature current

c.

To limit the NVC current

d.

To limit armature current

Discuss
Answer: (c).To limit the NVC current
Q47.
What will be the γ value for starter taking 4 steps, where ratio of resistance at maximum allowable current to armature resistance is equal to 1.8?

a.

1.2164

b.

1.8

c.

2.2468

d.

0.8220

Discuss
Answer: (a).1.2164
Q48.
Maximum allowable current for a 240-V DC shunt motor is equal to 65 A. Minimum allowable current for same is equal to 40 A. What will be the value of γ?

a.

0.6153

b.

1.265

c.

1.625

d.

2.652

Discuss
Answer: (c).1.625
Q49.
For a certain machine having γ = 1.8, we are using starter with 5 steps. What will be the resistance at step 3 if step 2 resistance is equal to 2 Ω?

a.

2.111

b.

1.111

c.

3.6

d.

10.8

Discuss
Answer: (b).1.111
Q50.
Which of the following is the correct formula for calculating step resistance?

a.

γ = rₙ/rₙ₋₁

b.

γ = rₙ/rₙ₊₁

c.

γ = rₙ*rₙ₋₁

d.

γ = rₙ*rₙ₊₁

Discuss
Answer: (a).γ = rₙ/rₙ₋₁
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