The Complete Guide to Automatic Changeover Switch

04th Jun 2023
woman turning off the light-switch in the hall

Automatic Changeover Switches, also known as Automatic Transfer Switches (ATS), are critical devices used in electrical systems to ensure seamless and automatic switching between power sources. In this comprehensive guide, we will explore the definitions, types, functions, and applications. Whether you are a homeowner, business owner, or electrical professional, this guide will provide valuable insights into the importance of Automatic Changeover Switches.

What is an Automatic Changeover Switch

Automatic Changeover Switches are used in residential settings to switch between the main utility power and backup generators. They provide homeowners with an uninterrupted power supply during power outages, ensuring the functioning of essential appliances and systems.

An Automatic Changeover Switch is a device that allows for the automatic transfer of power supply between two sources. It monitors the availability and quality of the primary power source and, in case of a power outage or voltage drop, swiftly switches to the secondary power source to ensure an uninterrupted power supply.

Types of Automatic Changeover Switches

  • Open Transition ATS

Open Transition ATS is the most common type of Automatic Changeover Switch. It briefly interrupts the power supply during the switching process, resulting in a momentary power outage. It is suitable for applications where a short interruption is acceptable, such as in industrial settings or backup power systems.

  • Closed Transition ATS

Closed Transition ATS, also known as make-before-break ATS, ensures a smooth and seamless transfer of power between sources. It overlaps the connection between the primary and secondary sources, eliminating power interruption during the switching process. Closed Transition ATS is commonly used in critical applications where uninterrupted power supply is essential, such as data centers or healthcare facilities.

Functions of Automatic Changeover Switches

  • Power Source Monitoring

Automatic Changeover Switches continuously monitor the availability and quality of the primary power source. They detect power outages, voltage fluctuations, or other abnormalities, initiating the switching process to the secondary power source when necessary.

  • Seamless Power Transfer

The primary function of an Automatic Changeover Switch is to ensure a seamless transition between power sources. They automatically transfer the load from the primary source to the secondary source without interruption, preventing downtime and ensuring an uninterrupted power supply.

  • Safety and Protection 

Automatic Changeover Switches provide safety features such as electrical isolation and protection against power surges or voltage imbalances. They help safeguard electrical equipment and prevent damage caused by irregular power supply.

Applications of Automatic Changeover Switches

  • Residential Applications

Automatic Changeover Switches are crucial components in electrical systems, ensuring seamless power transfer between primary and secondary sources. They provide an uninterrupted power supply, protect equipment, and offer peace of mind in various applications.

  • Commercial and Industrial Applications

ATS finds extensive use in commercial and industrial applications where continuous power supply is critical. They are employed in businesses, hospitals, data centers, manufacturing facilities, and other establishments to ensure uninterrupted operations and protect sensitive equipment.


When it comes to high-quality Automatic Changeover Switches, TOSUNlux is a reputable manufacturer to consider. With their expertise in electrical protection solutions, TOSUNlux offers a comprehensive range of reliable and innovative Automatic Changeover Switches that meet industry standards.

We have more than 31 years experience

Our Strength


Request a Quote