Avoiding pitfalls in coordination of multi-mode UPS and STS

Multi-mode uninteruptible power supplies (UPS) combine protection and efficiency by switching between different operating modes depending on the quality of the input mains. Static transfer switches (STS) also switch between multiple feed paths depending on the quality of each source. Therefore, the deployment of multi-mode UPS in conjunction with STS poses significant challenges. This presentation discusses common pitfalls in the coordination of these two devices by presenting experimental results from a sample installation.