What are power transformers?

Power transformers are electrical devices, used to transfer electrical energy from one circuit to another by the principle of electromagnetic induction. Its main role is in stepping up the voltage and stepping down the voltage levels. They are also called static devices, as they do not contain any rotating components. They are mainly employed in electric power systems to transmit and distribute electrical energy across various electrical devices and consume less power due to their low current consumption.


The main components of the power transformer are:

  • Primary winding - It is the coil that is present on the input side of the transformer.
  • Secondary winding - It is the coil that is present on the output side of the transformer.
  • Magnetic core - It is used for the efficient transmission of electrical energy from the primary winding to the secondary winding.

The other components of power transformers are insulating materials, Buchholz relay, bushings, conservator, transformer tank, breather, cooling system, breather, explosion vent, and tap changer.


The power transformer works on the principle of Faraday's law of electromagnetic induction. The three major components such as primary winding, secondary winding, and the magnetic core play a pivotal role. The alternative current initially flows through the primary winding and then passes through the magnetic core. As a result, there is a change in the magnetic field and the change in the magnetic field gives rise to the new flow of the current which flows from the other end of the transformer. The power transformers modify the voltage by stepping up and down the voltage levels, and the transformed or modified voltage levels will protect the device by preventing the damages caused due to variations in voltage levels and ensuring maintenance of the voltage levels as per the requirements of varied electronic devices.

Major types of power transformers

Step-up Transformer - It is used to increase the voltage levels and promote the long-distance transmission of the electric current across the devices.

Step-down Transformer - It is used to decrease the voltage levels and ensure the safe transmission of the electric current across the devices.

Distribution Transformers – It is used to amplify the voltage in such a way that is distributed to the terminal units efficiently.

The other types of power transformers are core-type transformers, Autotransformers, Three-phase transformers, shell-type transformers, Single-phase transformers, Berry-type transformers, Isolation transformers, Toroidal core transformers, Air core transformers, Iron core transformers, and Ferrite core transformers.

The power transformers are used for various purposes, but majorly they are employed to step up and down the voltage levels. It also ensures the safe transmission of electrical energy across the varied electric devices without any obstruction and prevents damages such as electric shocks, and short circuits.

What Are Power Transformers?