Can you name the two types of auto-transformers?

Here are two common types of autotransformers:

Single-phase autotransformer

Mainly used in single-phase AC circuit, common in some small electrical equipment voltage regulation, starting and other occasions. For example, in some laboratory equipment, single-phase autotransformers can be used to regulate the voltage to meet the voltage requirements of different experiments. It has the characteristics of simple structure, small size and low cost.

Three-phase autotransformer

It is used in three-phase AC power system and plays an important role in power transmission, industrial production and other fields. For example, in the starting process of some large motors, three-phase autotransformers can reduce the starting current and protect the motor and the power grid. It is generally more economical and efficient than a combination of three single-phase autotransformers and takes up less space.