electrical

Transformer MCQ Objective Questions and Answers Page - 3

1.

Power transformed from primary to secondary depends upon

Answer/ Hint      

Answer : D

Explanation :

2.

A transformer is supplying pure resistive (unity pf) load. The

Answer/ Hint      

Answer : B

Explanation :

3.

In a transformer supplying inductive load

Answer/ Hint      

Answer : D

Explanation :

4.

The phasor diagram of transformer on load can be drawn only if we know

Answer/ Hint      

Answer : D

Explanation :

5.

When a transformer is operating on no load, the primary applied voltage is approximately balanced by

Answer/ Hint      

Answer : A

Explanation :

6.

In the transformer circuit mode, the core loss is represented as a

Answer/ Hint      

Answer : C

Explanation :

7.

Full load voltage regulation of a power transformer is zero when power factor of the load is near

Answer/ Hint      

Answer : A

Explanation :

8.

In a transformer, zero voltage regulation at full load is

Answer/ Hint      

Answer : B

Explanation :

9.

Positive voltage regulation is an indication of ____load

Answer/ Hint      

Answer : C

Explanation :

10.

A 4 kVA, 400/200V single-phase transformer has resistance of 0.02 pu and reactance of 0.06 pu. Its actual resistance and reactance referred to hv side, are respectively

Answer/ Hint      

Answer : B

Explanation :

11.

If the percentage resistance of a power transformer for secondary side si 2.5 percent and turn ratio is 1:10 , the percentage secondary resistance referred to primary will be

Answer/ Hint      

Answer : B

Explanation :

12.

In a 3-phase, 5kV, 5MVA system, what is the base impedance?

Answer/ Hint      

Answer : A

Explanation :

13.

In a power transformer iron loss remain practically constant from no load ot full load. This is because

Answer/ Hint      

Answer : A

Explanation :

14.

In a power transformer, if in place of sinusoidal wave, a peaked wave voltage is fed to the primary

Answer/ Hint      

Answer : D

Explanation :

15.

The use of higher flux density in the transformer design

Answer/ Hint      

Answer : A

Explanation :

16.

The chemical used in breather for transformer should have the quality of

Answer/ Hint      

Answer : B

Explanation :

17.

The chemical used in breather is

Answer/ Hint      

Answer : D

Explanation :

18.

The transformer rating are usually expressed in terms of

Answer/ Hint      

Answer : D

Explanation :

19.

The noise resulting from vibrations of laminations set by magnetic forces is termed as

Answer/ Hint      

Answer : C

Explanation :

20.

Hysteresis loss in a transformer varies as (Bmax = max. flux density)

Answer/ Hint      

Answer : B

Explanation :

21.

Material used for construction of transformer core is usually

Answer/ Hint      

Answer : D

Explanation :

22.

The thickness of laminations used in a transformer is usually

Answer/ Hint      

Answer : A

Explanation :

23.

The function of conservator in a transformer is

Answer/ Hint      

Answer : D

Explanation :

24.

The highest voltage for transmitting electrical power in India is

Answer/ Hint      

Answer : D

Explanation :

25.

In a transformer the resistance between its primary and secondary is

Answer/ Hint      

Answer : D

Explanation :

26.

A transformer oil must be free from

Answer/ Hint      

Answer : D

Explanation :

27.

A Buchholz relay can be installed on

Answer/ Hint      

Answer : D

Explanation :

28.

Gas is usually not liberated due to dissociations of transformer oil unless the oil temperature exceeds

Answer/ Hint      

Answer : D

Explanation :

29.

The main reason for generation of harmonics in a transformer could be

Answer/ Hint      

Answer : D

Explanation :

30.

Distribution transformers are generally designed for maximum efficiency around

Answer/ Hint      

Answer : D

Explanation :

31.

Which of the following property is not necessarily desirable in the material for transformer core?

Answer/ Hint      

Answer : C

Explanation :

32.

Star/star transformers work satisfactorily when

Answer/ Hint      

Answer : B

Explanation :

33.

Delta/star transformers work satisfactorily when

Answer/ Hint      

Answer : C

Explanation :

34.

The yoke sections of transformers employing hot rolled laminations is made 15 percentage more than that of core in order to

Answer/ Hint      

Answer : B

Explanation :

35.

The joints in the transformer core lamination are staggered so as to

Answer/ Hint      

Answer : D

Explanation :

36.

The degree of mechanical vibration caused by core lamination in a transformer depends on

Answer/ Hint      

Answer : D

Explanation :

37.

The noise, in a transformer, caused by vibrations of laminations set by magnetic forces, is termed as

Answer/ Hint      

Answer : B

Explanation :

38.

The primary and secondary windings are interlaced for

Answer/ Hint      

Answer : B

Explanation :

39.

The leakage flux of primary and secondary windings can be reduced to the minimum by

Answer/ Hint      

Answer : B

Explanation :

40.

The concentric windings are used in core type transformers with _____winding placed next to the core

Answer/ Hint      

Answer : A

Explanation :

41.

Low voltage windings are placed next to the core in the case of concentric windings as in this case _____is/are reduced

Answer/ Hint      

Answer : D

Explanation :

42.

in a power transformer

Answer/ Hint      

Answer : C

Explanation :

43.

In transformers, the primary and secondary are interlaced so that

Answer/ Hint      

Answer : A

Explanation :

44.

The secondary of a current transformer is always short-circuited under operating conditions because it

Answer/ Hint      

Answer : A

Explanation :

45.

In a transformer the resistance between its primary and secondary should be

Answer/ Hint      

Answer : D

Explanation :

46.

A good voltage regulation of a transformer means

Answer/ Hint      

Answer : A

Explanation :

47.

For a transformer, operating at constant load current, maximum efficiency will occur at

Answer/ Hint      

Answer : D

Explanation :

48.

Which of the following protection is normally not provided on small distribution transformers?

Answer/ Hint      

Answer : B

Explanation :

49.

Which of the following act as a protection against high voltage surges due to lighting and switching?

Answer/ Hint      

Answer : A

Explanation :

50.

The efficiency of two identical transformers under load conditions can be determined by

Answer/ Hint      

Answer : B

Explanation :

51.

Which of the following insulating materials can be withstand the highest temperature safely?

Answer/ Hint      

Answer : C

Explanation :

52.

Which of the following parts of a transformer is visible from outside?

Answer/ Hint      

Answer : A

Explanation :

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