Online UPS and isolation transformers for hospitals
The load list in a hospital is not one load. Theatres, imaging, ICU and the server room each need a different answer, and the specification has to hold up in an NABH audit.
What actually goes wrong
Hospital power is graded by how long the load can be off. An operating theatre light and a ventilator can tolerate nothing. An MRI gradient amplifier draws enormous pulsed current and objects to a supply that sags under it. A CT scanner is intolerant of common-mode noise on the earth reference. And the whole essential-services board has to transfer to the DG and back without anyone in the building noticing. One 100 kVA UPS across the lot is the wrong shape of solution.
What to get right
The decisions on this list are the ones that are expensive to change after the equipment is on site.
Theatres and ICU — IT earthing
Operating theatres and intensive care are usually wired as IT (isolated terra) systems: an ultra isolation transformer plus an insulation monitoring device, so a first earth fault raises an alarm instead of tripping the supply during a procedure.
Imaging — pulsed load
CT and MRI draw short, very high current pulses. UPS and cable sizing must be against the peak, not the average, or the voltage sags every time the machine fires.
Noise floor
Monitoring and imaging equipment measures microvolt signals. Ultra isolation with over 100 dB common-mode attenuation is standard practice, not an upgrade.
Lift rescue
Stretcher and passenger lifts need a lift inverter so a car does not stall between floors during a power cut. This one gets found in audits.
Battery room siting
Hydrogen venting and heat mean the battery bank does not belong in an unventilated cupboard beside the plant room. Runtime is set by ambient temperature as much as by Ah.
Documented maintenance
Accreditation requires evidence of preventive maintenance and battery testing. Our AMC report is written so it can be handed straight to an auditor.
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.
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.
Lift Inverter
Not a rescue device that parks the car and stops. The lift keeps running — normal service, normal speed, up to eight hours on battery — so a power cut in a residential tower is something the residents never find out about.
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.
Servo Voltage Stabilizer
5 kVA to 500 kVA, air or oil cooled, correcting to ±1% output. The right first fix when the MIDC feeder swings all day and the equipment keeps tripping on undervoltage.
Through the life of the machine
Hospitals & Diagnostics — questions we get asked
Anything not covered here, call us — most of it is faster to answer on the phone.
What UPS capacity does a hospital need?
It is not one figure. Split the load into grades: no-break (theatres, ICU, ventilators, imaging consoles), short-break (lifts, general lighting, HVAC controls) and non-essential. Size a UPS against the no-break load with headroom for the pulsed peaks, and let the DG and ATS cover the short-break load. We do the load grading as part of the survey.
Why does imaging equipment need an isolation transformer?
Two reasons. It gives the machine a separately derived, cleanly earthed neutral, which removes earth-loop noise from the signal chain. And in an IT-earthed theatre or ICU it is what makes a first earth fault an alarm rather than a trip. Most imaging manufacturers specify it explicitly in their site preparation documents.
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.