12. Transformers

Transformers are used to change Alternating Current voltages. This is done to reduce energy loss throughout the National Grid. Transformers are made of two coils of wire wrapped around an Iron core.
A single oil cooled transformer. Notice its ability to transform 3 phases to 220KV - Image: Heurisko Ltd.
Isolating transformers were commonly used for protecting workers but are being replaced by RCD or Residual Current Devices such as this - Image: Heurisko Ltd.

Transformers are simple electrical devices that have

  • two separate coils of wire
  • an iron core
  • no moving parts.

How transformers work

Transformers have two electrical paths connected by a magnetic path.

They work in the following way:

  • The first coil produces a magnetic field
  • This magnetic field produces electricity in the second coil.
  • The iron core makes the transformer more powerful.

Transformers do not work with Direct Current.