How transformers work
A basic transformer transmits electrical energy from one circuit to another. It generally acts to reduce the voltage of electricity as it travels from power plants into homes. Electricity is generated in a conventional power plant as the burning of fossil fuels heats up water, causing steam to rise and push generator turbines round. This mechanical energy is converted into electrical energy as it travels through wires and reaches transformers. At this point, electricity has a very high voltage, which is necessary if it is to pass through electrical wires from the power plant and into buildings. Along the way, this electrical energy meets a series of transformers that steadily lower its voltage until it reaches a level that's safe for homes and offices. These transformers are known as "step-down transformers".
Most transformers consist of an iron core surrounded by two coils of insulated wire. One coil, which is attached to an alternating current, is known as the primary coil. The alternating current produces a constantly varying magnetic field around the primary coil. This varying magnetic field then produces an alternating current in the other coil, known as the secondary coil, which is connected to a different electric circuit. In step down transformers, the primary coil is more tightly wound than the secondary coil, which contributes to reducing the voltage of electricity as it is distributed.
However, some transformers are used to increase the voltage of the electricity that travels through it. These are known as "step-up" transformers. In this type of transformer, the secondary coil has a greater number of turns than the primary coil.
Identifying transformers
Transformers are most commonly seen mounted to electricity poles, as electrical energy is distributed from power plants to homes across a country. However, they have domestic uses too. The AC adapter on a laptop, for instance, acts as a transformer. That's because the voltage of electricity coming from a plug point may be too high for the low-voltage parts inside a laptop, making a step-down transformer a necessary component.
In business, however, transformers are much larger. Buying transformers can be very expensive for power plants and businesses, and some may opt for transformer rental when they need extra capacity.
Harvey McEwan writes to offer information on a variety of areas, from transformer rental to gift ideas. View Harvey's other articles to find out more.
