Working principle of power transformer

1. A power transformer is a special transformer that shares a set of coils for output and input. Different taps are used for boosting and lowering the voltage, with the voltage of the taps that are less than the shared coil decreasing and the voltage of the taps that are more than the shared coil increasing.
2. In fact, the principle is the same as that of a regular transformer, except that its primary coil is its secondary coil. A typical transformer uses electromagnetic induction on the left primary coil to generate voltage on the right secondary coil, while an autotransformer affects itself.
3. An autotransformer is a transformer with only one winding. When used as a step-down transformer, a portion of the wire turns are extracted from the winding as the secondary winding; When used as a step-up transformer, the applied voltage is only applied to a portion of the winding turns. The part of the winding that belongs to both primary and secondary windings is usually referred to as the common winding, while the rest of the autotransformer is called the series winding. Compared with ordinary transformers, autotransformers with the same capacity are not only smaller in size, but also more efficient, and the larger the transformer capacity, the higher the voltage. This advantage becomes even more prominent. Therefore, with the development of the power system, the improvement of voltage levels, and the increase of transmission capacity, self coupling transformers have been widely used due to their large capacity, low loss, and low cost.