• Categories:Industry News
• Author:
• Origin:
• Time of issue:2019-05-06
• Views:0

(Summary description)
　　1. Single-phase transformer and three-phase transformer

　　Simply put, a transformer used for single-phase alternating current is called a single-phase transformer, and a transformer used for three-phase alternating current is called a three-phase transformer. From the appearance, there are two high-voltage porcelain bushings, two or four low-voltage porcelain bushings are single-phase transformers; there are three high-voltage porcelain bushings, three low-voltage porcelain bushings (some have a shorter one next to it) The porcelain bushing) is a three-phase transformer. Their internal coil connections are also different. A single-phase transformer has only one set of high and low voltage coils, and its high voltage coil has two terminals; the low voltage coils mostly have 4 terminals, and two voltages can be obtained by connecting them in series or in parallel. For example, in some small distribution transformers, low-voltage coils can be used in series to get 220 volts, and in parallel, they can get 110 volts.



　　The primary coil and secondary coil of a three-phase transformer are usually connected by three sets of coils inside the transformer, and then lead to the outside of the oil tank through a ceramic bushing. The three sets of coils have different connection methods. One connection method is called star connection, and the symbol is Y. That is, one end of each set of coils is led out of a terminal (a total of three terminals), and the other ends are connected together, called the neutral point (or midpoint), which is led to the outside of the fuel tank through a shorter porcelain sleeve, called the middle point. Neutral point terminal (some transformers do not have a neutral point terminal outside). 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 another set of coils, as if a triangle, and then a terminal is drawn from each connection point.



　　The primary and secondary coils of the three-phase transformer can be connected in different ways as required. For example, the nameplate of some transformers is marked with a "Y-△" symbol, indicating that the primary coil of this three-phase transformer is star-connected and the secondary coil is delta-connected. The voltage of a three-phase transformer is divided into two types: phase voltage and line voltage. When the transformer adopts delta connection, the line voltage is equal to the phase voltage; when adopting the star connection, 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 a mistake when using it.



　　Two, double coil, three coil and single coil transformer

　　Transformers equipped with high-voltage and low-voltage coils are called double-wound transformers. For example, the nameplate of the transformer reads 35 kV/10 kV, indicating that this is a double-wound 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. Get a voltage of 10 kV.



　　Some transformers are equipped with high-voltage, medium-voltage and low-voltage coils, which are called three-volume transformers. For example, the nameplate of the transformer reads 110 kV/35 kV/10 kV, indicating 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 KV, when connected to a 110 kV power supply, two voltages of 35 kV and 10 kV can be obtained.



　　There are also a few special transformers, which have one high-voltage and two identical low-voltage coils, also called three-volume transformers; some have one high-voltage and three low-voltage coils, called four-volume transformers. The high-voltage coil of some transformers leads to two terminals, and a connector is drawn from the half-waist of the coil, and a terminal is drawn out. Some of the primary coils are used as secondary coils. In fact, there is only one coil, so it is called a single-wound transformer. , Also called autotransformer. This kind of transformer uses less materials and is low in cost, and is more economical when used in some occasions. However, since its high-voltage coil and low-voltage coil are directly connected, certain safety measures are required, so the use occasions are subject to certain restrictions.