The description of auto transformer
Autocoupling is the meaning of electromagnetic coupling. Ordinary transformers transfer energy through the electromagnetic coupling of the primary and secondary coils. There is no direct electrical connection between the primary and secondary sides and there is a direct electrical connection between the primary and secondary sides of the auto transformer. Auto transformer is part of the high voltage coil. An auto transformer is a transformer whose primary and secondary windings are on the same winding. According to the structure that can be subdivided into adjustable pressure type and fixed type.
The features of auto transformer
(1) Because the calculated capacity of the auto transformer is less than the rated capacity. Therefore, at the same rated capacity, the main size of the auto transformer is small, and the effective materials (silicon steel sheets and wires) and structural materials (steel) are reduced accordingly, thereby reducing costs. The reduction of effective materials results in a corresponding reduction in copper and iron consumption, so the efficiency of the auto transformer is higher. At the same time, due to the reduction in main size and quality, a single transformer with a larger capacity can be manufactured under allowable transportation conditions.
⑵ Because the short-circuit impedance standard value of the auto transformer is smaller than that of the double-winding transformer, the voltage change rate is small, but the short-circuit current is large.
(3) As there is a direct electrical connection between the primary and secondary of the auto transformer, when the overvoltage on the high voltage side causes serious overvoltage on the low voltage side. To avoid this danger, lightning arresters must be installed once or twice.
⑷ In general transformers. On-load voltage regulators are often connected to a grounded neutral point, so that the voltage level of the voltage regulator can be lower than when the line is regulated. The neutral voltage regulating side of the auto transformer will bring about the so-called related voltage regulating problems. Therefore, when the on-load voltage regulation of the auto transformer is required, only line-side voltage regulation can be used.
The principle of auto transformer
1. An auto transformer is a special transformer that shares a set of coils for output and input. Step-up and step-down are implemented with different taps. The voltage of the part with less than the common coil is reduced. The voltage of the part with more than the common coil is increased. high.
⒉In principle, it is the same as an ordinary transformer, except that its primary coil is its secondary coil. Generally, a transformer uses a primary coil on the left to generate voltage through the secondary coil on the right. The auto transformer affects itself.
⒊An auto transformer is a transformer with only one winding. When used as a step-down transformer, a part of the turns are drawn from the winding as a secondary winding. When used as a step-up transformer, the applied voltage is only applied to part of the winding. on. Generally, the part of the winding that belongs to both the primary and secondary is called the common winding, and the rest of the auto transformer is called the series winding. Compared with the ordinary transformer, the auto transformer with the same capacity is not only small in size but also highly efficient. The larger the capacity, the higher the voltage. This advantage is even more prominent. Therefore, with the development of the power system, the improvement of the voltage level and the increase of the transmission capacity, the auto transformer is widely used due to its large capacity, small loss and low cost.