Riello Sentryum S3T 20 Online UPS 20kVA / 20kW – Three-Phase

The Riello Sentryum S3T 20 is a 20kVA / 20kW three-phase online double-conversion UPS from Riello UPS's third-generation transformerless Sentryum range. It delivers full rated power at unity power factor (kVA = kW) with efficiency of up to 96.5%, in a compact cabinet suited to server rooms, small data centres, network and telecom infrastructure, and building-critical systems. A graphic touchscreen, USB and RS232 ports, communication card slots, and parallel capability for up to 8 units make it easy to monitor, expand, and build redundancy.

ONLINE DOUBLE CONVERSION: CLEAN, REGULATED POWER ALL THE TIME

In online double-conversion mode the UPS rebuilds the output power continuously, so connected equipment always runs on clean, regulated power with no transfer time when the mains fails, drops, or surges. Servers, storage, network gear, and industrial controls stay isolated from brownouts, spikes, and noise on the utility supply. Selectable Online, Eco, and Smart Active modes let you balance protection and efficiency.

20KVA = 20KW: UNITY POWER FACTOR

The S3T 20 delivers its full 20kW of real power at unity power factor, so a 20kVA rating means 20kW of usable load. Many UPS systems at this size give up 10% or more of their rating to a lower power factor, so unity PF lets you size for the load you actually have.

TRANSFORMERLESS THREE-PHASE (S3T)

The S3T version has three-phase input and three-phase output. The transformerless design is compact and light for its capacity, and Riello builds on its Multi Sentry series with an optimised card layout that reduces components, cables, and interconnections, which saves installation space and eases maintenance. An isolation transformer is optional.

WIDE INPUT TOLERANCE FOR UNSTABLE MAINS

Input is 380 / 400 / 415V three-phase + neutral with ±20% voltage tolerance at full load and a 40–72Hz frequency window, at 0.99 input power factor. The UPS rides through poor mains conditions without going to battery. The bypass accepts 180–264V (phase to neutral) at 50 or 60Hz (selectable).

UP TO 96.5% EFFICIENCY

Efficiency reaches up to 96.5% in online double-conversion mode. Less wasted energy means lower running cost and less heat to remove from the room.

HIGH OVERLOAD AND SHORT-CIRCUIT CAPACITY

The UPS handles 125% overload for 10 minutes and 150% for 1 minute, and short circuits of 270% for 200ms and 150% for 300ms. Sudden peak loads are absorbed without transferring to bypass.

LOW HARMONIC DISTORTION

The control system keeps output voltage distortion below 1% with resistive loads and below 1.5% with non-linear loads such as switch-mode server power supplies. The sinusoidal output has a 3:1 crest factor and ±0.5% static stability.

BUILT FOR REAL ENVIRONMENTS

Sentryum uses a dual-core DSP processor and high-frequency three-level inverters (18kHz), with components engineered to operate at temperatures up to 40°C. A closed-loop parallel arrangement keeps a parallel system running even if the connecting cables are severed.

GRAPHIC TOUCHSCREEN + LED STATUS BAR

A graphic touchscreen shows measurements and operating states clearly, and an LED status bar shows the UPS's condition at a glance.

PARALLEL UP TO 8 UNITS

Connect up to 8 units in parallel to increase capacity or build N+1 redundancy as your load grows.

CONNECTIVITY AND MANAGEMENT

USB and RS232 ports, communication card slots, and a contact interface (5 opto-isolated inputs, 4 output relays) support network and building-management integration. Compatible with Riello UPS management software including PowerShield3 and PowerNetGuard.

FLEXIBLE BATTERY OPTIONS

Smart Battery Management extends battery life. The range supports VRLA AGM, GEL, NiCd, lithium-ion, and supercapacitor batteries, and a 20A extended battery charger kit is available for long-autonomy setups.

THREE CABINET SIZES

Compact (CPT), Active (ACT), and Xtend (XTD) cabinets cover restricted spaces up to large internal battery capacity. See the variant table for sizes and weights.

BUILT FOR

- Server rooms and small data centres

- Network, telecom, and security infrastructure

- Industrial control and process equipment

- Healthcare and laboratory equipment

- Building-critical systems

KEY SPECIFICATIONS

- Model: Riello Sentryum S3T 20

- Type: Online double-conversion, transformerless, standalone

- Power: 20kVA / 20kW (unity power factor)

- Phases: Three-phase input / three-phase output (S3T)

- Input: 380 / 400 / 415V three-phase + N, ±20% at full load, 40–72Hz, PF 0.99

- Bypass: 180–264V (Ph-N), 50 or 60Hz selectable, ±5%

- Output: 20000VA / 20000W, 29A (inverter) / 32A (bypass), sinusoidal, 3:1 crest factor, ±0.5% static stability

- Efficiency: up to 96.5%

- Overload: 125% for 10 min, 150% for 1 min

- Short Circuit: 270% for 200ms, 150% for 300ms

- Output Voltage Distortion: < 1% resistive, < 1.5% non-linear

- Inverter: High-frequency three-level (18kHz), dual-core DSP

- Display: Graphic touchscreen + LED status bar

- Interfaces: USB, RS232, communication card slots, contact interface (5 inputs / 4 relays)

- Parallel: up to 8 units

- Batteries: VRLA AGM, GEL, NiCd, Li-ion, supercapacitors

- Operating Environment: 0–40°C, 5–95% RH non-condensing

- Colour: RAL 7016 anthracite grey

- Software: PowerShield3, PowerNetGuard

- Manufacturer: Riello UPS