Important interview questions for transformer

TRANSFORMER:

1.what is a transformer?

The transformer is a static machine used for transforming power from one circuit to another without changing frquency.

Transformer operates on ac supply. The transformer working on the principle of an mutual induction.

It doesn't have rotating or moving parts so transformer is a static machine.

2.what is the working principle of transformer?

It is based on the faraday's law of electro magnetic induction.

Mutual induction between two or more winding is responsible for transformation action in an electrical transformer.

According to the faraday's law: rate of change of flux linkage with respect to time is directly proportional to the induced emf in the conductor or coil.

3.what are the main parts of transformer?

Primary winding.

Magnetic core.

Secondary winding.

4.what are the accessories of a transformer?

Bucholz relay.

Silica gel breather of transformer.

Oil surge relay.

Radiator of transformer.

Magnetic coil gauge.

LV and HV winding temperature indicator.

Oil temperature indicator.

Pressure release valve.

5.What are the types of connection of 3 phase transformers?

Star-delta transformer.

Delta-star transformer.

Star-star transformer.

Delta-delta transformer.

Star-zigzag transformer.

Delta-zigzag transformer.

6.what are the condition for parallel operation of transformer?

When two or more transformers are run in parallel, they must satisfy the following conditions.

Same voltage ratio of transformer.

Same percentage impedance.

Same polarity.

Same phase sequence.

7.What is meant by ideal transformer?

It is an imaginary transformer which does not have any loss on it.

It means no core loss, copper loss and any other loss.

Efficiency is 100%

8.what are the losses in transformer?

Two electrical losses.

1.core loss or iron loss.

- Hysterisis loss.

- Eddy current loss.

2.copper loss.

9.what are the types of transformer?

Step up & step down transformer.

Single phase & three phase transformer.

Electrical power transformer, Distribution transformer & Instrument transformer.

Two winding transformer & auto transformer.

Outdoor & Indoor transformer

Oil cooled & dry type transformer.

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