# Transformer MCQs Part 25

Transformer MCQs Part 25

Contents

## For large-sized transformers, the cores are built up to nearly circular cross-section, this is done in order to reduce

For large-sized transformers, the cores are built up to nearly circular cross-section, this is done in order to reduce:

1. Iron losses
2. Copper losses
3. Eddy current losses
4. Leakage reactance

Explanation: In case of large sized transformers the cores are build up to the nearly circular cross section in order to reduce the copper losses.

See complete List of Transformer MCQs here.

## Laminating transformer core results in decreased

Laminating transformer core results in decreased:

1. Hysteresis loss
2. Leakage reactance
3. Eddy current losses
4. Copper losses

Correct answer: 3. Eddy current losses

## A 10 V source of internal resistance 5 Ω is connected to load of 5 Ω through a transformer. For maximum power transformer, the turns ratio of transformer should be

A 10 V source of internal resistance 5 Ω is connected to load of 5 Ω through a transformer. For maximum power transformer, the turns ratio of transformer should be:

1. 1:1
2. 1:2
3. 2:2
4. 1:4

Zp/Zs = (N1/N2)^2

(N1/N2)^2 = Zp/Zs

(N1/N2)^2 = 5/5

(N1/N2)^2 = 1:1

## The load on transformer is 3 ∠0° Ω or 3 ∠20° Ω. The efficiency of transformer will be

The load on transformer is 3 ∠0° Ω or 3 ∠20° Ω. The efficiency of transformer will be:

1. Greater for 3 ∠0° Ω
2. Greater for 3 ∠20° Ω
3. Same of both
4. None of above

Correct answer: 1. Greater for 3 ∠0° Ω

Explanation: For both loads, the copper and core losses will be same. However, the output power for 3 ∠0° Ω will be greater.

## The secondary of PT is generally designed for

The secondary of PT is generally designed for:

1. 12 V
2. 24 V
3. 120 V
4. 220 V