In this article, we consider what a transformer is. The types of transformers will be described, the principle of operation and design will also not be left without attention. It is worth noting that this is a type of static (stationary) AC machines that are used for various purposes not only in everyday life, but also in industry. For example, to account for consumed electricity. But first things first.
What is this device?
This is an electric static machine that is used to convert current or voltage. Moreover, several types of devices can be distinguished, depending on which network the power is supplied from. So, three-phase ones have three network windings, which are switched on according to the "star" or "triangle" circuit. In this we can draw an analogy with induction motors. There are various types of power transformers, which will be discussed below.
But in everyday life, devices are used in which one network winding. In addition, there is at least one secondary, which serves to power the devices. For example, in lamp technology, power transformers are used , which have several secondary windings. There was a need to receive several voltage values from one device: 6.3 V, 250 V. In addition, current transformers can be found in everyday life. They are installed in electric meters and are used to operate the control device.
Design
It is difficult to single out the base of the transformer, but if you rely on weight, then this is undoubtedly the core (magnetic core). It is made of steel sheets that are assembled together and tightly pulled together. This allows you to get the maximum possible cross section of the magnetic circuit. But not only steel can be used, cores are often made of ferromagnets. This substance, which in properties is very similar to metal, but has a slightly different structure. There are certain types of transformers, photos of the main structures are given in the article.
There are at least two windings in the design. One (primary) supply voltage is applied. With the second, third, Nth, low voltage is removed with a frequency and shape similar to the input. Power windings consist of copper wire. It is wound on a frame located around the magnetic circuit. When voltage is applied to the primary circuit, an alternating magnetic field appears , which induces an emf in the secondary winding. As a result of this, a certain potential difference appears at the output.
Power transformers
These types are those that convert electricity to networks. This is not only a transformer installed in substations. The types of power transformers are diverse, they serve not only to lower the voltage from 110 kV, for example, to 6 kV, in the case of a substation. These include devices used in power supplies of household radio equipment. In fact, everyone has a similar design, there are common nodes.
Even welding transformers, the types of which are diverse, have a similar structure. There are only minor nuances, for example, power machines at substations are equipped with an oil cooling system, while welding machines work without it. But the latter have an adjustment of the output current. This is necessary for welding metals of various thicknesses. Well, the devices used in everyday life are completely devoid of such adjustments.
Auto transformers
An autotransformer is one of the types in which the primary and secondary windings are connected directly. This allows you to get not only the electrical connection in the device, but also electromagnetic. Typically, an autotransformer has three outputs, and this allows you to get different voltage values. A distinctive feature of autotransformers is a high efficiency. But there is one significant drawback - the primary and secondary circuits are not electrically isolated from each other. It is used for the most part to control the power of the consumer such a transformer. Types of transformers for other purposes are discussed below.
Measuring
For use in electrical installations of alternating current created a special type of transformers - measuring. Thanks to them, the limits of measuring devices increase. In addition, they allow to measure the current flowing through it without an electrical connection to the power wire. In other words, without galvanic coupling, it is possible to control the flowing current in the circuit. But two types of measuring devices can be distinguished - voltage and current transformers. There are various types of current transformers, their difference in size and scope.
Current transformers allow conversion. At the same time, a large current flowing in the circuit decreases to a safe value. Moreover, it is safe at the output for control or measurement systems, alarm and protection devices. The primary winding is a segment of the conductor, around it a secondary winding is held. With the latter, a current of 1 or 5 Amps is removed. But voltage transformers are designed for a different purpose. They produce undervoltage to measure performance. With their help, galvanic isolation of protective devices from a circuit with a high voltage is carried out.
Impulse
This type of device is used for highly specialized purposes. It is needed to convert a series of pulsed signals. Moreover, the duration of one pulse can reach several tens of microseconds. And there is one small feature - only the amplitude of the signal changes, but not its shape. By the way, there are certain types of transformer protections , pulse ones are also equipped with circuits that prevent excess voltage or current.
As a rule, pulse devices are used in circuits in which a rectangular signal flows. Often this type of device is used in television technology. They convert short pulses of a video signal with a very high duty cycle. And at the output you get the signal in its original form, but with increased amplitude.
Conclusion
Now you know what a transformer is. We looked at the types of transformers and saw that they all have slight differences, despite the fact that the design is much similar. Please note that safety precautions must be followed when working with any electrical devices. In addition, for maintenance of AC power networks it is necessary to have a tolerance group.