Transformer — its working, construction, types, and uses

What is the Transformer?

Transformers are electrical devices that convert the voltage to a higher or lower value while ideally keeping the power constant.

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Why do we need them?

With the development of AC power sources, the need for transformers was also born. In the early times, DC power transmission was done in the resulting in greater losses and poor efficiency. With the invention of the transformer, this issue is resolved and AC power transmission became prominent.

Construction of a Transformer:

A transformer consists mainly of a core, windings, and a tank, however, bushings, breathers, radiators, and conservators are also present in some transformers.

shell and core type laminations
shell and core type laminations

Working principle:

transformer working principle
transformer working principle
By BillC at the English language Wikipedia, CC BY-SA 3.0, Link

“The Rate of change of flux linkage with respect to time is directly proportional to the EMF induced in a conductor or coil”

This change in the magnetic field induces a voltage on the secondary coil which is proportional to the number of turns on the windings. This can be further understood by the following equation:

Transformer turns ratio:

Both the windings on a transformer I.e. primary and secondary have a specific number of turns. The ratio of the number of turns on the primary winding to the number of turns on the secondary winding is known as the turns ratio.

transformer turns ratio
transformer turns ratio

Ideal Transformer:

An ideal transformer is a transformer which gives a power output that is exactly equal to the power input. This means that it does not have any type of loss.

ideal transformer
ideal transformer

How an Ideal Transformer is different from a Real Transformer?

In actuality, we have transformers that consist of some power losses; hence the output power is never equal to the input power of the transformer.

Transformer Equivalent Circuit:

transformer equivalent circuit
transformer equivalent circuit
transformer equivalent circuit efficiency
transformer equivalent circuit efficiency
transformer equivalent circuit efficiency
transformer equivalent circuit efficiency
transformer equivalent circuit efficiency
transformer equivalent circuit efficiency
transformer equivalent circuit efficiency
transformer equivalent circuit efficiency
voltage regulation
voltage regulation
voltage regulation where
voltage regulation where

Transformer types and their applications

Step-up transformer: ​These transformers increase the lower voltage level on the primary side to a higher voltage value on the secondary side. In this case, the secondary winding has a greater number of turns than the primary one.

Step-up transformer
Step-up transformer
Step-down transformer
Step-down transformer

Limitations of a transformer:

It is also important to note here that a transformer will only operate in AC. This is because a Direct Current (DC) will produce a constant magnetic field instead of a changing magnetic field and hence no emf will be induced in the secondary winding.

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