Servo stabilizers and UPS for CNC machine shops
A CNC controller that resets mid-cycle scraps the job and can crash the tool. On MIDC feeders that is a voltage problem far more often than an outage problem.
What actually goes wrong
Machine shop supply around Pune sags through the morning shift as the estate loads up and swings when a large motor next door starts direct-on-line. The controller browns out, the drive faults, the job is scrapped, and the fault log says nothing useful. Meanwhile the VFDs on your own machines are injecting harmonics back into the same panel that feeds the controllers.
Working in cnc & machine shops
What to get right
The decisions on this list are the ones that are expensive to change after the equipment is on site.
Voltage first
Log the incoming voltage for a week before buying anything. If the problem is sag rather than outage, a servo stabilizer fixes it at a fraction of the cost of a UPS.
Unbalanced phases
Machine shops run a lot of single-phase load spread unevenly. A balanced stabilizer corrects on the average and leaves the low phase low — you need an independent-phase unit.
Controller vs spindle
You rarely need to back up the spindle drive. Protecting the controller, the drives’ control supply and the probing system covers the actual failure mode at a much smaller rating.
VFD harmonics
Your own drives pollute the panel that feeds your controllers. An isolation transformer ahead of the control supply separates the two.
Imported machines
A 60 Hz or 200 V machine from Japan, Korea or the US needs a static frequency converter, not a transformer. Running it on 50 Hz overheats the motors.
Shop-floor enclosure
Coolant mist and metal dust. IP54 or better, and filters that actually get changed on the AMC visit.
What we supply into this sector
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.
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.
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.
Static Frequency Converter
Run 60 Hz equipment on a 50 Hz supply — or generate a clean 400 Hz for aviation ground power — with no rotating parts and no maintenance schedule.
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.
01Do CNC machines need a UPS or a stabilizer?
Usually a stabilizer, sometimes both. If the machine faults on undervoltage several times a day but rides through actual outages, the problem is voltage and a servo stabilizer is the correct and much cheaper fix. If it goes down whenever the feeder does and a lost job is expensive, add a UPS on the controller circuit only. Log the supply for a week first — it makes the answer obvious.
02Can I run a 60 Hz imported machine on Indian 50 Hz supply?
Not safely. Motors run 17% slower, magnetising current rises and the windings overheat; frequency-referenced timers and control gear drift. A static frequency converter handles both the frequency and the voltage translation in one cabinet.
03Why does a CNC machine trip when nothing looks wrong with the supply?
Because the control sees things a panel meter does not. A CNC controller monitors its own DC bus and will fault out on a dip lasting a fraction of a second — far shorter than anything a voltmeter on the wall will show, and often caused by a large motor starting elsewhere in the shop. The trip is real; the evidence is just faster than the instrument. A power quality logger over a working week is the way to see it.
04Do I need a stabilizer or a UPS for a CNC machine?
It depends on whether your problem is voltage or interruption. If the supply is present but wandering outside the drive’s tolerance, a servo stabilizer fixes it and is the cheaper answer. If the supply disappears — even briefly — a stabilizer has nothing to stabilise and only a UPS keeps the control alive. Many shops need the stabilizer for the machine and a small UPS for the control and the CNC’s own PC.
05Does the whole machine need to be on backup, or just the control?
Usually just the control, and that is what makes it affordable. Keeping the spindle and axis drives running through an outage means a UPS sized for the full machine. Keeping the controller, the encoders and the PC alive means a small one — and that is enough to hold the part programme, the tool offsets and the axis positions so the job can resume instead of being re-datumed. Confirm what your controller needs to survive a shutdown before deciding.
06Will a stabilizer fix harmonics from my VFDs?
No, and it is worth being clear about that. A servo stabilizer corrects voltage magnitude; it does not remove harmonic distortion, and the VFDs in your own shop are usually the source. If the complaint is transformer heating, nuisance tripping or distorted waveform rather than high or low voltage, the answer is a harmonic study and possibly an isolation transformer or a filter — not a bigger stabilizer.
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.