Transformers

31. The degree of mechanical vibrations produced by the laminations of a transformer depends on

tightness of clamping
gauge of laminations
size of laminations
all of the above

Detailed SolutionThe degree

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of mechanical vibrations produced by the laminations of a transformer depends on

32. If R2 is the resistance of secondary winding of the transformer and K is the transformation ratio then the equivalent secondary resistance referred to primary will be

$$ rac{{{{ ext{R}}_2}}}{{sqrt { ext{K}} }}$$
$$ rac{{{{ ext{R}}_2}}}{{{{ ext{K}}^2}}}$$
$$ rac{{{ ext{R}}_2^2}}{{{{ ext{K}}^2}}}$$
$$ rac{{{ ext{R}}_2^2}}{{ ext{K}}}$$

Detailed SolutionIf

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R2
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is the resistance of secondary winding of the transformer and K is the transformation ratio then the equivalent secondary resistance referred to primary will be

33. In a transformer the tappings are generally provided on

primary side
secondary side
low voltage side
high voltage side

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41.5 48.3 47.8C117.2 448 288 448 288 448s170.8 0 213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z"/> Subscribe on YouTube
on" class="read-more button" href="https://exam.pscnotes.com/mcq/in-a-transformer-the-tappings-are-generally-provided-on/#more-48748">Detailed SolutionIn a transformer the tappings are generally provided on

34. The function of breather in a transformer is

to provide oxygen inside the tank
to cool the coils during reduced load
to cool the transformer oil

Detailed SolutionThe function of breather in a transformer is

35. Distribution transformers are generally designed for maximum efficiency around

90% load
Zero load
25% load
50% load

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button" href="https://exam.pscnotes.com/mcq/distribution-transformers-are-generally-designed-for-maximum-efficiency-around/#more-48536">Detailed SolutionDistribution transformers are generally designed for maximum efficiency around

36. The permissible flux density in case of cold rolled grain oriented steel is around

1.7 Wb/m2
2.7 Wb/m2
3.7 Wb/m2
4.7 Wb/m2

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around" class="read-more button" href="https://exam.pscnotes.com/mcq/the-permissible-flux-density-in-case-of-cold-rolled-grain-oriented-steel-is-around/#more-48308">Detailed SolutionThe permissible flux density in case of cold rolled grain oriented steel is around

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

fluctuating load
poor insulation
mechanical vibrations
saturation of core

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transformer could be" class="read-more button" href="https://exam.pscnotes.com/mcq/the-main-reason-for-generation-of-harmonics-in-a-transformer-could-be/#more-48151">Detailed SolutionThe main reason for generation of harmonics in a transformer could be

38. Transformer breaths in when

load on it increases
load on it decreases
load remains constant
none of the above

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in when" class="read-more button" href="https://exam.pscnotes.com/mcq/transformer-breaths-in-when/#more-48034">Detailed SolutionTransformer breaths in when

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

Magnetostriction
Boo
Hum
Zoom

Detailed SolutionThe noise

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

40. Material used for construction of transformer core is usually

wood
copper
aluminium
silicon steel

Detailed

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213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z"/> Subscribe on YouTube
SolutionMaterial used for construction of transformer core is usually

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