What's the difference between ATS (Automatic Transfer Switch) and STS (Static Transfer Switch)

ATS (Automatic Transfer Switch) and STS (Static Transfer Switch) have the following differences:

-Working principle

-ATS: It belongs to a mechanical structure that relies on electromagnetic locks, mechanical interlocks, contactors, circuit breakers, etc. to achieve power conversion, and automatically switches between two power sources through motor drive or electromagnetic drive.

-STS: It belongs to the electronic circuit structure, with intelligent control board, high-speed thyristor, and circuit breaker as the main components, using electronic switches for switching without mechanical action.

-Switching speed

-ATS: The conversion speed is relatively slow, usually above 100 milliseconds, and can reach up to 80 milliseconds at the fastest.

-STS: The switching speed is extremely fast, usually within 8 milliseconds, and some can reach 5 milliseconds.

-Applicable scenarios

-ATS: Suitable for loads such as lighting, motors, and fire-fighting facilities that are insensitive to power outages and can tolerate brief power outages.

-STS: Suitable for IT equipment, data centers, medical equipment, communication base stations, and other loads that are sensitive to power outages and require uninterrupted power supply.

-Power synchronization requirements

-ATS: No need for strict synchronization of two power sources.

-STS: It is required that the two power sources must be basically synchronized, otherwise there may be switching failures or short circuits.

-Range of current usage

-ATS: It can generally reach below 3200A.

-STS: Usually below 1000A.

-Volume and Cost

-ATS: It has a relatively large volume and generally requires the configuration of a controller, resulting in relatively low cost.

-STS: Relatively small in size and relatively high in price.