A power transformer is a stationary electrical device and belongs to a motor with a zero rotational speed. When the power transformer works in the system, it can transfer the electrical energy from its primary side to the secondary side through the conversion of electromagnetic energy, and at the same time increase or decrease the voltage according to the needs of transmission and distribution. Therefore, it plays an important role in the whole process of production, transmission and distribution of electric energy. In the entire power system, the capacity of the transformer is usually about 3 times more than the capacity of the generator.
Transformers work on the principle of electromagnetic induction. The transformer body is mainly composed of a winding and a core. When working, the winding is the "electrical" path, and the core is the "magnetic" path, and plays the role of the winding skeleton. When the primary side inputs electrical energy, an alternating magnetic field is generated in the iron core due to its alternation (that is, the electrical energy becomes a magnetic field); due to the enthalpy chain (penetration), the magnetic force lines of the secondary winding constantly alternate, so the induction is induced. The secondary electromotive force, when the external circuit communicates, generates an induced current and outputs electrical energy outwardly (that is, it is converted into electrical energy by magnetic energy). This "electric-magnetic-electrical" conversion process is based on the principle of electromagnetic induction, which is the working process of the transformer.