View Full Version : cnc lathe and power interruptions

01-07-2010, 05:51 PM
Due to the ever changing winter weather where I live (lots of freezing rain)
we have lots of small power interruptions. Just long enough to shute down windows.
The mach-3 system on my lathe hates this and so do I.
Usually means I have to reset my tool positions.
Are any of you using UPS on your system and if so what size and type?

01-07-2010, 05:55 PM
Size would depend on your CNC system/pc, that said im running a 1.4kw one on my main insaneo gaming PC that I got for $230~ recently.. and a 600VA for my other PC thats near its limit that I got for free ages ago..

Only the 1.4kw one is currently riged up to be able to shut down its host PC on low battery however..

01-07-2010, 08:32 PM
motorworks, I have the same problem. No easy solution. Yes, a UPS for the PC is quite feasible, but I'd also need a UPS for the Geckos and their transformer, plus...... I'd need a UPS for the lathe motor, too, otherwise the geckos would continue trying to cut a workpiece that is no longer spinning.

01-07-2010, 09:22 PM
Perhaps a Princess Auto 6500 watt diesel gen-set is the answer. :)

I am going to get the UPS for the computer right now as most of the 'outs' have
been at night when I was not in the shop....
and I hate having to reset everything.
The mill is still on the Dos-Turbo same computer for 7 years. Power comes and
goes and NEVER a problem with the system.
Dos is bullet proof. Just wish someone would put some more work into Turbocnc.

John Stevenson
01-08-2010, 04:19 AM
Pay The Damn Lecky Bill.........................


01-08-2010, 04:54 AM
I run the computer and the stepper drivers from a regular UPS. The spindle motor is a 24vdc 1/2 hp brushless motor. I haven't been having much trouble with power so far this winter but if it does deteriorate I will bring in from the garage a pair of 55 amp hour VRLA batteries with smart charger to run the spindle. Don't forget to include a work light on the UPS circuit.

01-08-2010, 10:08 AM
I have done a lot of data center infrastructure design over the years and what you are trying to do is actually a little complicated. A lot of the UPS systems use a mechanical relay to switch from mains to battery backup and there is a slight delay. Most computers are fairly forgiving on this, but a cnc running hard is not. For equipment that required NO power interruption/voltage sags or spikes/other anomalies you really just need to run them off of a DC to AC true sine wave inverter directly from batteries and use the mains power to charge the batteries. Higher end industrial UPS systems often do this but we generally used Xantrex Trace Grid Tie Inverters running off of a batter bank. Because the equipment ran directly from the inverters there was no fluctuation caused by city power faults.

To scale this down to run a cnc, look at sine wave solar inverters rated for about twice what your cnc requires. Try to find one that has a built in battery management system and then add a couple of deep cycle batteries and you will have a real solution. The other option is to find a small diesel generator and run the cnc directly from it. That is a pretty common practice in places with dirty power.