Which of the following statements are true regarding parts of a transformer?

(i) The thickness of laminations varies from 0.35 mm to 0.5 mm.

(ii) The material used for breather is blue in colour when it is damp and whitish pink when dry.

(iii) For a constant input voltage, the output voltage can be varied over a small range by providing few tapings.

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SSC JE Electrical 06 Jun 2024 Shift 2 Official Paper - 1

Answer 1

Transformer

A transformer is a device that is used to increase or decrease the supply voltage without a change in the frequency of AC between circuits.
There are usually two coils primary coil and a secondary coil on the transformer core.
The core of a transformer is made up of silicon steel. The resistance of the core should be increased to hysteresis losses. Therefore by adding 3% silicon to the iron core, the hysteresis loss is reduced.
The laminations of a transformer core are made from silicon steel and typically have thicknesses ranging from 0.35 mm to 0.5 mm. This lamination reduces eddy current losses by increasing the resistance to the flow of eddy currents.
The core laminations are joined in the form of strips. The eddy current loss is minimized by using the thin core of lamination.
The breather used in transformers, typically containing silica gel, is blue when dry and turns pink when it absorbs moisture. This color change indicates the need to replace or regenerate the silica gel.
Transformers can have tap changers that allow for variations in output voltage while keeping the input voltage constant. By tapping into the winding at various points, the output voltage can be adjusted over a small range.