In modern industry, transportation, post and telecommunications, and scientific research, auto transformers have become an indispensable and important component in power conversion and electronic equipment with their unique structure and wide application fields. Autotransformers are special transformers whose primary and secondary windings are on the same winding and achieve energy transfer through electromagnetic coupling.

The working principle of the auto transformer is based on Faraday's law of electromagnetic induction. It is composed of a main winding and a secondary winding that share the same magnetic circuit. The main winding includes an input winding and an output winding, which are directly connected in series to form a tight electromagnetic coupling system. When an alternating current is passed through the input winding, the changing current will generate an alternating magnetic field in the iron core, and then induce an electromotive force in the secondary winding to achieve voltage conversion. Since the main winding and the secondary winding share the same magnetic field, the energy transfer efficiency is higher and the loss is smaller.

Auto transformers have many advantages over ordinary double-winding transformers. It is small in size, light in weight, and easy to transport and install. Since it only contains one shared coil, the required materials and costs are greatly reduced, and the insulation structure is also simplified, reducing the use of insulation materials and shielding. The autotransformer has a wide adjustment range. It can change the voltage of the output winding by adjusting the current in the input winding, and is suitable for a variety of complex working conditions. It has high energy transfer efficiency and low loss, meets the national low-carbon standards, and has properties such as heat resistance, moisture resistance, stability, and chemical compatibility.

In terms of application areas, the auto transformer has demonstrated its unparalleled flexibility and breadth. In power systems, autotransformers are often used for step-up or step-down. Its high efficiency, energy saving, lightness and compactness make it widely used in high-power transmission transformers. On industrial production lines, autotransformers provide a stable voltage supply for various equipment to ensure the smooth progress of the production process. In medical equipment, such as CT machines, X-ray machines, etc., autotransformers provide precise voltage control to ensure the safe operation of equipment. In addition, autotransformers are also widely used in fields such as building lighting systems, communication systems, and computer networks. By adjusting the voltage, they ensure the stable lighting of lamps and extend their service life while providing stable power support.

There are also some potential challenges and limitations for autotransformers. Since the primary and secondary windings are directly connected, they may be affected by external electromagnetic interference in some cases. This factor must be fully considered during design and use.

Looking to the future, the auto transformer industry will usher in a broader development prospect. As the scale of national investment in the power system continues to increase, my country's power system industry is gradually developing in the direction of high voltage and large capacity. Autotransformers are widely used in power systems due to their high working efficiency and low production costs. In terms of transportation, autotransformers are widely used in high-speed rail systems to ensure the normal operation of traction substations, return circuits, and overhead contact networks in high-speed rail systems.