UPS System for Bridgeport Series II mills

[scmw]

Hi,

I'm fairly new to the forum and learning a ton of valuable information. I recently purchased some Bridgeport Series II NC mills that have been converted to Mach 3. I also have an A2Z modified Sherline 2000 with IMService's servo system and DeskCNC.

This past week I encountered some problems running a program on my Sherline due to stress on the electric grid. The 90 degree temps in Illinois caused a lot of air conditioners to start up and continuously run thus causing fluctuation within the grid.

I experienced several hiccups where the servos would simply stop running. Fortunately I didn't lose my registration and was able to home the spindle each time. The temporary fix was to slow down the program and get the part made, albeit a bit later than I wanted to but it did get done.

This has me thinking of how to avoid this in the future. I'm going to use an APC or other brand of UPS (Uninterruptible Power Supply) on the smaller mill. I'm wondering whether there might be a suggested size of UPS to use on the Bridgeports. They currently have steppers although I intend to upgrade them to servos sometime in the fall.

Is anyone using a UPS to protect their controllers and ancilliary equipment? If so, what should I look for with larger mills?

Thanks,
Terry

[Jim Shaper]

You might be able to find a 230v UPS on CL if you look hard enough. Fleabay would be another option, but shipping is going to kill you if it includes batteries. Then there's the batteries which only last 4-5 years (100% runtime). My neighbor gave me one a couple years back, the batteries would've cost a few hundred to replace (30A@230v). I ended up trading it on two smaller units (worth $100) which I now use to protect my DRO's.

The bigger units are used in server rooms running multiple computers, so that's who you'll want to check with for surplus suppliers.

Simply having the control computer on a UPS might be enough, assuming the fault in motion would trip an error and halt the control. If that's the case, you'll be fine with any of the off the shelf units.

[macona]

Are you using home switches and setting offsets? That will help you get going.

And decent sized UPS will do. Since you are using steppers I am sure all of your electronics short of the spindle are 115v.

If it is a low voltage/brownout issue another option is a CVT (Constant Voltage Transformer), it, like its name implies, keep the output constant no matter what the voltage is within a given range. The simplest ones are the ferroresonant type. You would only need one on the drive side as the computer power supply should be happy down to 100v, maybe even down to 90.

[Ohio Mike]

An APC brand Smart UPS will do similar. It will attempt to pull more amps at low voltage in order to correct for the line fault. If all else fails then it moves to battery. Also if I recall correctly the Smart UPS series allows you to adjust the set points for high and low voltage. I've used them for years in commercial network installations, and have my whole office plugged into one. I can't speak as to sizing for your application.

[kc5ezc]

APC Smart UPS comes in XS and RS flavors. At least in the 1500VA and under versions. The RS only knocks off the highs. The XS takes care of the high and low swings.
Sizing is dependent on how long you want to run after the power goes out as well as the VA required. APC will help with an email or phone call.