Best Tutorial on Transformer

In this tutorial, we are going to learn about Transformer.

What is Transformer?

  • One of the most important components in the entire power system.
  • There are millions of transformers in our power system.
  • It is considered as the backbone of the power system due to its huge importance.
  • It is used in electrical circuit to change the voltage of electricity flowing in the circuit. Transformers can be used either to increase the voltage (Stepping) or decrease the voltage (step down).

How Transformer is Work?

  • It is an electrical designed to convert alternating current (AC) from one voltage to another. It can be “step up” or “step down” voltages and it works on the magnetic induction principle. When the voltage is introduced to one coil, then it is  called the primary, it magnetizes the iron core.
  • Below is the formula for transformer work.

The number of primary turns NP / the number of primary turns NS = turn on secondary coil: Turns on Primary Coil

VoltageOUT / VoltageIN = Turn on secondary coil / Turns on Primary


Why required Step up and Step down voltage?

  • It is because high voltage improves efficiency by reducing heat loss in the power lines. But high voltages are too dangerous for use in home, so step down transformers are used locally to reduce the voltage to safe levels.
  • As apparent power generated S = 3 * V * I cosØ.
  • At constant power – As V increases, Current decreases which decreases losses in power system.

How many types of Transformers?

Current Transformer –

It is a device which is used to reduce or multiply an alternating current and it produces a current in its secondary which is proportional to the current in its primary. It is along with voltage or potential transformers are instrument transformers.

Voltage Transformer –

  • It is also called the potential transformers, in this transformer; there is a parallel-connected type of instrument transformer. It is designed to present a negligible load to the supply being measured and have an accurate voltage ratio and phase relationship to enable accurate secondary connected metering.

Capacitor Voltage Transformer –

  • It is capacitor voltage transformer (CVT), it is a transformer which used in power systems to step down extra high voltage signals and provide a low voltage signal, for operating a protective relay.
  • Capacitor Voltage Transformer (CVT), it is single phase device which used for measuring voltage excess of one hundred kilovolts there the use of voltage transformers will be uneconomical.

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