Online UPS and transfer switches for data centres
Redundancy topology, battery runtime to DG pickup, and heat rejection. At this scale the UPS is the easy part of the specification.
What actually goes wrong
A server room fails in one of three ways: the UPS itself becomes the single point of failure, the battery bank turns out to hold ninety seconds instead of fifteen minutes, or the room cannot reject the heat the UPS adds to it. Every one of those is a design decision made at purchase, not a fault that develops later.
Working in data centres & server rooms
What to get right
The decisions on this list are the ones that are expensive to change after the equipment is on site.
Redundancy topology
N+1 covers a module failure and suits most rooms. 2N gives two independent paths to dual-corded equipment and is only worth it when the load is genuinely dual-corded.
Runtime to DG pickup
If a DG picks up in 15 seconds, you need enough battery to cover it with margin for a failed start — typically 10–15 minutes, not 5.
Input harmonics
A rectifier front end injects harmonics back onto the supply. Our units run active power-factor correction above 0.90, which keeps the draw close to unity and stops upstream transformer heating.
Heat rejection
A 100 kVA UPS at 94% efficiency rejects roughly 6 kW into the room. That is nearly two tons of cooling that has to be in the HVAC design.
Lithium footprint
At 40 kVA and above, LiFePO₄ takes about a third of the floor space, lasts three to four times as long and gives real state-of-charge telemetry.
Monitoring integration
SNMP and Modbus output into your existing NMS or BMS, so a UPS alarm reaches the same place every other alarm does.
What we supply into this sector
Online UPS
True double-conversion topology from 3 kVA to 200 kVA across three series, with single-phase or three-phase output. Zero transfer time, pure sine output held to ±1%, and up to 96% efficiency. Built and load-tested in Pune.
Automatic Transfer Switch (ATS)
The supply you are on fails, and the load moves to the one that has not — with nobody at the panel. 10 A to 150 A, single phase and three phase.
Isolation Transformer
Galvanic separation between supply and load, with electrostatic shielding that attenuates common-mode noise by 100 dB or better. 1 kVA to 500 kVA.
Industrial Battery Charger
SMPS chargers from 5 A to 30 A and float-cum-boost chargers from 5 A to 200 A, sized to the bank rather than to a catalogue number.
Load Bank
Standby plant is only as good as its last test. A load bank applies a real, controlled, measurable load so the capacity written on the nameplate is the capacity you actually have.
Through the life of the machine
Questions we get asked
Anything not covered here, call us — most of it is faster to answer on the phone.
01How much battery backup does a server room need?
Enough to cover DG start with margin, or enough for an orderly shutdown if there is no DG. With a generator, 10–15 minutes is the usual specification — the DG picks up in 15 seconds, and the balance covers a failed first start. Without a generator, size against how long a clean shutdown of your stack actually takes, which is usually longer than people assume.
02Is N+1 redundancy worth the extra cost?
If the room cannot be taken down for a maintenance window, yes — N+1 lets you service one module while the others carry the load, and that is often the real justification rather than failure protection. If you can schedule a Sunday-night outage twice a year, a single unit with a maintenance bypass may be enough.
03How much UPS runtime does a server room actually need?
Enough to cover generator start and transfer, plus a controlled shutdown if the generator fails — for most rooms that is minutes, not hours. Sizing for a long autonomy is usually the wrong instinct: the battery bank grows, the room needs more floor and cooling, and the money is better spent on the generator and on testing the changeover. If there is no generator, the target changes completely and the runtime has to cover an orderly shutdown of everything on the floor.
04Does a server room UPS need to be online double conversion?
For IT load, yes in almost every case. Double conversion rebuilds the output waveform rather than passing the input through, so the load never sees the mains at all and the transfer to battery is not a transfer. Line-interactive units are cheaper and fine for a workstation, but they pass through supply disturbances and take milliseconds to switch, which is the wrong trade for equipment that costs more than the UPS.
05What power factor should I use to size a UPS for servers?
Work in kilowatts and take the figure from the equipment, not from the nameplate. Modern server power supplies have active PFC and run close to unity, so the old habit of assuming 0.8 understates the real kW a given kVA will carry. Getting this wrong in either direction is expensive: too low and you buy a machine you do not need, too high and you find the limit during a peak.
06Can one UPS feed both servers and the room’s air conditioning?
It can, but it usually should not. Cooling is a motor load with a large starting current and a very different duty from IT equipment, and putting it on the same machine sizes the UPS around the compressor rather than the servers. The common arrangement is IT on the UPS and cooling on the generator, with enough UPS runtime to bridge to the generator before the room gets warm.
We will do the load grading with you
Site survey, load list and a single-line diagram before anything is quoted. That is where the specification is actually decided.