electrical

Transformer MCQ Objective Questions and Answers Page - 2

1.

A single phase transformer rated for 220/240V,  50Hz operates at no load at 220 V , 40 Hz. This frequency operation at rated voltage  results in which one of the following

Answer/ Hint      

Answer : D

Explanation :

2.

A 50 Hz transformer having equal hysteresis and eddy current losses at rated excitation is operated at 45Hz at 90% of its rated voltage . Compared to rated operating point, the core loses under thi

Answer/ Hint      

Answer : C

Explanation :

3.

A single phase transformer when supplied form 220V , 50 Hz has eddy current loss of 50W. If the transformer is connected to a voltage of 330V, 50Hz the eddy current loss will be

Answer/ Hint      

Answer : B

Explanation :

4.

1 kVA, 230V, 50Hz single phase transformer has an eddy  current loss of 30 watts. The eddy current loss when the transformer is excited by a dc source of same voltage will be

Answer/ Hint      

Answer : D

Explanation :

5.

At 50 Hz operation, a single phase transformer has hysteresis loss of  200 W and eddy current loss of 100 W. Its core loss at 60 Hz operation will be

Answer/ Hint      

Answer : C

Explanation :

6.

Can a 50Hz transformer be used for 25Hz, if the input voltage is maintained constant at the rated value corresponding to 50H

Answer/ Hint      

Answer : B

Explanation :

7.

On no load phasor diagram of transformer, the core loss component of the current remains in phase with

Answer/ Hint      

Answer : B

Explanation :

8.

In a transformer core, third and fifth harmonic components of fluxes are respectively 10% and 4% of the fundamental flux. The third and fith harmonic induced emfs in the winding in terms of the fun

Answer/ Hint      

Answer : A

Explanation :

9.

If a sinusoidal voltage source is connected to a power transformer, its no load current would be

Answer/ Hint      

Answer : D

Explanation :

10.

In a transformer , the exciting current will be in phase quadrature with the impressed voltage provided

Answer/ Hint      

Answer : C

Explanation :

11.

The power factor of a power transformer on no load will bne about

Answer/ Hint      

Answer : D

Explanation :

12.

The power factor of a transformer on no loadis poor due to

Answer/ Hint      

Answer : A

Explanation :

13.

If in a transformer core a material having high reluctance path but having same hystersis loop is employed

Answer/ Hint      

Answer : B

Explanation :

14.

Primary winding of a transformer comprises of two identical windings in parallel. If one winding is removed, magnetizing current will b

Answer/ Hint      

Answer : C

Explanation :

15.

The core flux of a practical transformer  with a resistance load

Answer/ Hint      

Answer : A

Explanation :

16.

The inductive reactance of a transformer depends on

Answer/ Hint      

Answer : D

Explanation :

17.

The flux in transformer core

Answer/ Hint      

Answer : C

Explanation :

18.

The mutual flux in a loaded transformer can be varied by varying

Answer/ Hint      

Answer : D

Explanation :

19.

The primary ampere turns are counter balanced by

Answer/ Hint      

Answer : A

Explanation :

20.

In a transformer_____ decreases with the increase in leakage flux

Answer/ Hint      

Answer : C

Explanation :

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Transformer MCQ Objective Questions and Answers Page - 2