ATS vs STS
Q: What does an automatic transfer switch (ATS) do, and how does it compare to a static transfer switch (STS)?
A: An ATS allows two input supplies into one output supply. In UPS systems below 10 kVA, the ATS is typically a 19” rack-mount unit (e.g. Multi-Switch ATS) with two UPS-fed inputs and several IEC outlets — used to give single-cord IT and data-centre equipment two UPS supply sources, so failure of one UPS does not drop the load.
A STS (static transfer switch) is the more advanced technical equivalent designed for higher-power single- and three-phase applications, typically with one UPS feeding “input A” and another UPS feeding “input B” (see Master Switch in the Riello catalogue). STS uses solid-state thyristor switching for sub-millisecond transfer times.
Both belong to the Static Transfer feature family.
Connections
- Multi-Switch ATS — referenced, source: https://standbysystems.co.za/ups-batteries-questions-and-answers/
- Static Transfer — referenced, source: https://standbysystems.co.za/ups-batteries-questions-and-answers/
- Master Switch — referenced, source: https://standbysystems.co.za/ups-batteries-questions-and-answers/