The principle of operation of the transformer

With the discovery and industrial use of electricity, it became necessary to create systems for its transformation and delivery to consumers. This is how transformers appeared, the principle of operation of which will be discussed.

Their appearance was preceded by the discovery of the phenomenon of electromagnetic induction by the great English physicist Michael Faraday almost 200 years ago. Later, he and his American colleague D. Henry drew a diagram of the future transformer.

Faraday transformer

The first embodiment of the idea in iron took place in 1848 with the creation of an induction coil by the French mechanic G. Rumkorf. Russian scientists also contributed. In 1872, a professor at Moscow University A.G. Stoletov discovered a hysteresis loop and described the structure of a ferromagnet, and 4 years later, an outstanding Russian inventor P.N. Yablochkov received a patent for the invention of the first alternating current transformer.

How the transformer works and how it works

Transformers are the name of a huge "family", which includes single-phase, three-phase, step-down, step-up, measuring and many other types of transformers. Their main purpose is to convert one or more alternating current voltages into another based on electromagnetic induction at a constant frequency.

So, briefly, how the simplest single-phase transformer works. It consists of three main elements - primary and secondary windings and a magnetic circuit that unites them into a single whole, on which they are strung, as it were. The source is connected exclusively to the primary winding, while the secondary removes and transfers the already changed voltage to the consumer.

The principle of operation of the transformer

The primary winding connected to the network creates an alternating electromagnetic field in the magnetic circuit and forms a magnetic flux, which begins to circulate between the windings, inducing an electromotive force (EMF) in them. Its value depends on the number of turns in the windings. For example, to lower the voltage, it is necessary that there are more turns in the primary winding than in the secondary. This is how step-down and step-up transformers work.

An important design feature of the transformer is that the magnetic circuit has a steel structure, and the windings, usually in the form of a cylinder, are isolated from it, are not directly connected to each other and have their own markings.

Voltage transformers

This is perhaps the most numerous type of the transformer family. In a nutshell, their main function is to make the energy produced in power plants available for consumption by various devices. For this, there is a power transmission system consisting of step-up and step-down transformer substations and power lines.

Initially, the electricity generated by the power plant is fed to the step-up transformer substation (for example, from 12 to 500 kV). This is necessary in order to compensate for the inevitable losses of electricity during long-distance transmission.

The next stage is a step-down substation, from where electricity is supplied through a low-voltage line to a step-down transformer and then to the consumer in the form of a voltage of 220 V.

But the work of transformers does not end there. Most of the household electrical appliances around us - PCs, TVs, printers, washing machines, refrigerators, microwave ovens, DVDs, and even energy-saving light bulbs - have step-down transformers. An example of an individual "pocket" transformer is a mobile phone (smartphone) charger.

The huge variety of modern electronic devices and the functions they perform correspond to many different types of transformers. This is not a complete list of them: power, pulse, welding, isolation, matching, rotating, three-phase, peak transformers, current transformers, toroidal, rod and armor.

What are the transformers of the future

The transformer industry is considered to be very conservative. Nevertheless, she also has to reckon with revolutionary changes in the field of electrical engineering, where nanotechnology is becoming more and more vocal. Like many other devices, they are gradually getting smarter.

SF6 transformers

There is an active search for new construction materials - insulating and magnetic, capable of providing higher reliability of transformer equipment. One of the directions can be the use of amorphous materials, which will significantly increase its fire safety and reliability.

Explosion and fireproof transformers will appear, in which the chlorobiphenyls used to impregnate electrical insulating materials will be replaced by non-toxic liquid, environmentally friendly dielectrics.

SF6 transformers

An example of this is SF6 power transformers, where the function of a refrigerant is performed by non-combustible SF6 gas, sulfur hexafluoride, instead of far from safe transformer oil.

A matter of time is the creation of "smart" power grids equipped with semiconductor solid-state transformers with electronic control, with the help of which it will be possible to regulate the voltage depending on the needs of consumers, in particular, to connect renewable and industrial power supplies to the home network, or vice versa, to disconnect unnecessary ones when in they are not necessary.

Another promising direction is low-temperature superconducting transformers. Work on their creation began in the 60s. The main problem faced by scientists is the huge size of cryogenic systems required for the manufacture of liquid helium. That all changed in 1986 when superconducting high-temperature materials were discovered. Thanks to them, it became possible to abandon bulky cooling devices.

Transformer with semiconductor converter

Superconducting transformers have a unique quality: at a high current density, losses in them are minimal, but when the current reaches critical values, the resistance from zero level increases sharply.