When the commonly used power supply is detected to have deviations (such as voltage loss, overvoltage, undervoltage, phase loss, frequency deviation, etc.), the automatic transfer switch will automatically transfer the load from the commonly used power supply to the backup (or emergency) power supply. If the commonly used power supply returns to normal, the automatic transfer switch will automatically return the load to the commonly used power supply. When there is a deviation in the commonly used power supply, the automatic transfer switch will also transfer the load to the backup power supply. However, when the commonly used power supply returns to normal, the automatic transfer switch will not automatically return to the commonly used power supply, and manual intervention or backup power supply failure is required before returning.

Automatic transfer switch is an electrical device that plays a crucial role in emergency power supply systems. It ensures the continuous power supply and reliability of the load circuit by monitoring the status of the power circuit in real-time and automatically performing switching operations. During the power conversion process, the automatic transfer switch can ensure continuous power supply to the load circuit, avoid power interruption, and thus improve the reliability and stability of power supply. It is widely used in places that require high reliability power supply, such as hospitals, banks, power plants, chemicals, metallurgy, airports, docks, office buildings, hotels, shopping malls, sports fields, military facilities, etc.