Types Of Transformers

Large-scale transportation of electrical energy would not be possible without transformers. This is why they have been so important to the development of the electrical industry. However, not all transformers have the same characteristics, so it is good to know what the main types and their applications are.

It is good to start by defining what a transformer is, since it tends to be confused with the electric generator and other similar devices. It is an alternating current element that works as a static machine and has the function of varying the intensity or voltage of the current, but without changing the power or frequency. For this, the transformer passes the electricity through an electromagnet to transform it back into electricity. For its part, a silent electrical generator is simply a transducer that converts mechanical energy into electrical energy.

To understand how a transformer works, let’s remember that a magnet itself creates an invisible magnetic field around it, which goes from north to south. For its part, the electromagnet has wire turns, through which the electric current circulates, generating the magnetic field. In this sense, if there is no flow of electricity, the magnetism disappears. These are the main parts of a transformer and it was what the British physicist Michael Faraday used to lay the foundations for what we now know as electrical transformers.

Nowadays, although we may not realize it, transformers are making everything around us work, not only on a macro level, but also from a domestic point of view, for example, some small devices such as tin soldering irons do not need a transformer, but yes a welding machine, since it is in charge of increasing the current and decreasing the voltage. But if you want to know for sure what a transformer is for, we invite you to know its types, since each one has a different use, depending on its structure and design.

Classification of transformers according to their phase

According to their phase, electrical transformers can be single-phase and three-phase. The former are frequently used in general electrical power supplies, for example public lighting and heating systems. We can say that single-phase transformers are the most used to change the voltage in alternating current circuits.

For their part, three-phase transformers are used at high nominal powers and are composed of three single-phase connected to a single magnetic core. These types of transformers are essential for the distribution of electricity in cities.

As we can see, the difference between single-phase and three-phase is very simple, however, it can be crucial in some contexts, for example, in certain populations it is necessary to use a single-phase to three-phase transformer, since it serves to obtain three-phase power in areas where there is only single phase option. Instead, to connect single-phase loads to a three-phase network, a three-phase to single-phase transformer is necessary.


This works like a common electrical transformer, but has a single winding in the core, connected through 2 terminals for each circuit, so it is usually used as a voltage regulator.

Impedance transformer

It is a transformer with a powdered iron core, which is shaped like a ring or cylindrical bar. It is widely used to adapt antennas for telephones, network cards and televisions, among others. Previously, it was necessary to use this type of transformer to match the impedance of the tubes to that of the speakers in tube amplifiers.

Power transformer

This is a medium and high voltage transformer, which comes in different sizes depending on the need. They are specially designed to avoid the dissipation of energy in the form of heat during their operation, for this reason, they are used in electrical substations.

Measurement transformer

It must be taken into account that magnetic fields generate failures in the measurement instruments, this is where the measurement transformers are useful, since they allow isolating the protection devices from the high voltage, so it is possible to measure and monitor the current with greater accuracy, thus increasing safety, that is why they are widely used as a high voltage transformer.

Isolation transformer

In this case, each coil of the transformer has the same number of turns, so that the voltage applied to the input is the same as that obtained at the output. It is widely used as a protector of medical equipment, since it reduces electrical disturbances.

Step-down and step-up transformer

This is the quintessential voltage transformer. It is a device that allows the amount of electrical voltage to be controlled in order to precisely match it with the load requirements.

Brief history of the transformer

In 1831, Faraday discovered that by bringing the loop of an independent circuit and without any source closer to the electromagnetic field, it acquires electricity without barely touching the electromagnet. In addition, the scientist noted that the speed with which the circuit is approaching or moving away from the electromagnetic field can increase or decrease the amount of electricity.

Later, the alternating current transformer was created, where the magnetic field can fluctuate in the same way that the current rises and falls, so that the magnetic field is variable. In this case, there is no need to move the independent circuit closer or further apart to create the electricity. The next step was to use a more advanced independent circuit, with many turns just like the electromagnet coil. In this way, the scientists discovered that they could obtain a large amount of electrical energy.

But this device, which consisted of a magnetic coil with an electrical energy source and another circuit also with turns, did not completely convince the researchers, since the magnetic field lost a lot of energy. For this reason, in 1882 John Dixon Gibbs and Lucien Gaulard presented a device that had an iron core, which changed the operation of the transformer, since it allowed to concentrate and take advantage of all the magnetic energy.

It was the birth of a very powerful device, which in 1885 was improved by three Hungarian engineers from the Ganz company; Ottó Titusz Bláthy, Károly Zipernowsky and Miksa Déri, ​​who presented the DBZ model. Later, businessman George Westinghouse would buy the patent for this device that would forever transform the lives of Americans and the rest of the world.

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