AllInfoHub – MCQ Practice

Electrical Machines – Multiple Choice Questions (MCQs)

1. Which of the following machines works on the principle of Faraday's Law of Electromagnetic Induction?
- A. DC Motor
- B. Transformer
- C. Induction Motor
- D. All of the above
2. The efficiency of a transformer is maximum when:
- A. Copper losses are equal to iron losses
- B. Copper losses are less than iron losses
- C. Copper losses are greater than iron losses
- D. No-load losses are zero
3. Which of the following is not a part of a DC machine?
- A. Armature
- B. Field winding
- C. Commutator
- D. Slip rings
4. The main purpose of a commutator in a DC machine is to:
- A. Convert AC to DC
- B. Convert DC to AC
- C. Provide mechanical support
- D. Control speed
5. The direction of rotation of a DC motor can be reversed by reversing the direction of:
- A. Armature current only
- B. Field current only
- C. Both armature and field current
- D. Either armature or field current
6. A transformer transforms:
- A. Voltage
- B. Current
- C. Frequency
- D. Voltage and current
7. The core of a transformer is laminated to reduce:
- A. Hysteresis loss
- B. Eddy current loss
- C. Copper loss
- D. Leakage flux
8. The no-load current of a transformer is:
- A. Leading the voltage by 90 degrees
- B. Lagging the voltage by 90 degrees
- C. Almost purely reactive
- D. Almost purely resistive
9. Which test is conducted to determine the core losses (iron losses) of a transformer?
- A. Short-circuit test
- B. Open-circuit test
- C. Load test
- D. Swinburne's test
10. The short-circuit test on a transformer is performed at:
- A. Rated voltage and rated current
- B. Rated voltage and short-circuit current
- C. Reduced voltage and rated current
- D. Reduced voltage and short-circuit current
11. The slip of an induction motor is defined as:
- A. Ns - Nr / Ns
- B. Nr - Ns / Ns
- C. Ns / Nr
- D. Nr / Ns
12. The starting torque of a squirrel cage induction motor is generally:
- A. High
- B. Low
- C. Very high
- D. Zero

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Electrical Machines – Multiple Choice Questions (MCQs)

1. Which of the following machines works on the principle of Faraday's Law of Electromagnetic Induction?

2. The efficiency of a transformer is maximum when:

3. Which of the following is not a part of a DC machine?

4. The main purpose of a commutator in a DC machine is to:

5. The direction of rotation of a DC motor can be reversed by reversing the direction of:

6. A transformer transforms:

7. The core of a transformer is laminated to reduce:

8. The no-load current of a transformer is:

9. Which test is conducted to determine the core losses (iron losses) of a transformer?

10. The short-circuit test on a transformer is performed at:

11. The slip of an induction motor is defined as:

12. The starting torque of a squirrel cage induction motor is generally:

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