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How many types of transformers are there?


How many types of transformers are there?

Industry news
Release time:
2019/05/06 17:19
1. Single-phase transformer and three-phase transformer
Simply put, a transformer for single-phase AC is called a single-phase transformer, and a transformer for three-phase AC is called a three-phase transformer. In appearance, there are two high-voltage porcelain bushings, two or four low-voltage porcelain bushings are single-phase transformers; there are three high-pressure porcelain bushings and three low-pressure porcelain bushings (some have a shorter side next to them) The porcelain casing is a three-phase transformer. Their internal coils are also connected differently. A single-phase transformer has only one set of high and low voltage coils, and its high voltage coil has two terminals. Most of the low voltage coils have four terminals, and they can be connected in series or in parallel to obtain two voltages. For example, some small distribution transformers, which use a low-voltage coil in series, can get 220 volts and can be used in parallel to get 110 volts.

The primary coil and the secondary coil of the three-phase transformer are usually connected to the outside of the fuel tank through the porcelain casing after the three sets of coils are connected inside the transformer. These three sets of coils have different connection methods. A connection method is called a star connection and the symbol is Y. That is, one end of each set of coils is led out of one terminal (three terminals in total), and the other end is connected together, called a neutral point (or midpoint), and is led to the outside of the fuel tank through a short porcelain sleeve, called middle Sex terminal (some transformers have no neutral terminals). Another connection method is called delta connection and the symbol is △. That is, one end of each set of coils is connected to one end of the other set of coils, as if it were a triangle, and then a terminal is taken from each connection point.

The primary and secondary coils of a three-phase transformer can be wired differently as needed. For example, some transformers have a “Y-△” symbol on the nameplate, indicating that the primary coil of this three-phase transformer is a star connection and the secondary coil is a delta connection. The voltage of the three-phase transformer is divided into two types: phase voltage and line voltage. When the transformer is in delta connection, the line voltage is equal to the phase voltage; when the star connection is used, the line voltage is 1.732 times the phase voltage, and the voltage between each terminal and the neutral point is the phase voltage. Don't make mistakes when using it.

Second, two-volume, three-volume and single-volume transformers
A transformer with both high and low voltage coils is called a two-roll transformer. For example, the nameplate of the transformer says 35 kV / 10 kV, which means that this is a two-volume transformer. Its high-voltage coil is 35 kV, and the low-voltage coil is 10 kV. It can be connected to a 35 kV power supply. A voltage of 10 kV is obtained.

Some transformers are equipped with three types of coils: high voltage, medium voltage and low voltage, called three-volume transformers. For example, the transformer's nameplate says 110 kV / 35 kV / 10 kV, which means that this is a three-volume transformer, its high voltage coil is 110 kV, the medium voltage coil is 35 kV, and the low voltage coil is 10 Kilovolts, connected to a 110 kV power supply, can get 35 kV and 10 kV.

There are also a few dedicated transformers, one with a high voltage and two identical low-voltage coils, also known as three-volume transformers; some have a high voltage and three low-voltage coils, called four-volume transformers. Some high voltage coils of the transformer lead out two terminals, and a joint is taken from the half waist of the coil, and a terminal is taken out, and a part of the primary coil is used as a secondary coil. Actually, there is only one coil, so it is called a single coil transformer. Also known as autotransformer. This type of transformer uses less material and is less expensive, making it economical to use in some applications. However, since its high-voltage coil and low-voltage coil are directly connected, certain safety measures are required, so the use is limited.