The Sentryum series S3U by Riello UPS (a Riello Elettronica group company) consists of a transformer-free UPS with three-phase input and output. Two models are available — the S3U model features a single switch without a separate bypass, and the S3U SW model features four switches and separate bypass. They are available in 10, 20, and 30 kVA. Sentryum S3U has been designed to offer full power up to an ambient temperature of 40°C and a high-overload capacity of 110% for 60 minutes, 125% for 10 minutes, and 150% for 1 minute.