The Riello Sentryum S3U is a third-generation, transformer-free online double-conversion UPS designed to protect mission-critical loads in data centers, medical, industrial, emergency, and transport applications. Available in six power ratings from 10 to 60 kVA (208V, three-phase in/out, 60 Hz), it delivers up to 95.5% efficiency thanks to a three-level IGBT inverter topology and advanced digital control. The design emphasizes a compact footprint (as little as 0.45 sqm for the 30 kVA unit), near-unity input power factor (0.99), very low input current distortion (under 3%), and full power output up to 40°C ambient—all of which translate into lower installation and running costs while minimizing impact on the upstream grid or generator.
Beyond raw efficiency, the Sentryum S3U focuses on battery health and operational flexibility. Its Smart Battery Management system supports VRLA, AGM, GEL, and NiCd batteries with multiple recharge methods, temperature-compensated charging, deep-discharge protection, and high charging current (up to 36A) for extended-runtime setups. The unit offers four operating modes (Online, ECO, Smart Active, and Standby Off), parallel configuration of up to eight units for N+1 redundancy, and comes in two frame options (single-switch S3U or four-switch S3U SW). Monitoring and control are handled through a color graphic touchscreen, a status LED bar, USB and RS232 ports, programmable input/output contacts, and multi-platform shutdown software—making it a versatile power-protection solution for small data centers and other critical environments.