An automatic transfer switch is an electrical device composed of one or more transfer switch devices and other necessary devices, used to monitor power circuits (such as voltage loss, overvoltage, undervoltage, phase loss, frequency deviation, etc.), and automatically convert one or more load circuits from one power source to another. In the electrical industry, it is also known as a "dual power automatic transfer switch" or "dual power switch.".

Transfer switches have advantages such as multiple contacts, multiple positions, small size, reliable performance, convenient operation, and flexible installation. The use of conversion switches can simplify control or measurement circuits, avoid operational errors, and reduce the number of components used. A conversion switch is a switching device that plays a crucial role in a circuit. It achieves circuit switching and control through the combination and rotation of multiple contacts. It is widely used in machine tool electrical control, motor control, and measurement systems.