Introduction: Repurposing a Dead UPS in to a CNC Motor Controller Enclosure

By

Just for clarification, I did not make a CNC motor controller out of a UPS; I’m only using the UPS housing as an enclosure for a commercial motor controller.

I purchased a table top CNC router from eBay, and the controller came mounted on a board.I didn’t pay a much for it so it wasn’t too big of a deal.But I soon found that the motor controller would be much better off in a protective case.It would also be nice to have an on/off switch. I initially planned on creating my own custom box using my router but I figured this would be more time effective and more durable.

This project is pretty easy but does require some soldering, drilling, and cutting.
I completed this project in about 4 hours, for a cost of about $5.00.

Step 1: Tools & Materials Needed.

The Tools Required for this project are pretty basic.

Multi-meter for finding out the pin-outs of the switches, and double checking wiring.

Screwdriver you may need both a Philips and a flat.

A Utility knife (razor blade) for cutting the Sintra.

Wire strippers these will get a lot of use in this project 4 wires X 3 motors  X 3 connections

Step Drill (or a regular drill bit) for drilling the vent holes and any necessary mounting holes.

Cordless Drill (optional) this makes taking apart the UPS very easy and quick.

A soldiering iron. 

Step 2: Tearing Down the UPS

Important!  REMOVE THE BATTERY FIRST, after all the whole purpose of a UPS is to produce 110V even when it's unplugged. There is usually a compartment that opens up to allow access for replacing the battery, usually on the bottom or possibly under the front cover.

This step is pretty easy just remove all of the items inside the box.  Keep any parts that will be needed to maintain the enclosures shape.   I won't go into too much detail because each UPS will be slightly different.  Make sure you leave enough of the enclosure to put it back together solid.  The most this should require is unplugging wires and removing screws.




Step 3: Adding the Power Supply.

The power supply fits nicely into the enclosure but make the Power supply easier to mount I installed a piece of Sinra (expanded PVC) to the bottom.  I first cut it to size and then attached it with 4 screws up from the bottom.

I then used screws to screw down the power supply through existing holes in the power supply housing.

I left the power supply wiring as complete as possible as to make it easier to wire when that step comes.

Step 4: Adding the Motor Controller.

This width of the UPS ended up being a little tighter than I planned and I didn't have a lot of room to work with. I explored some options with Sinatra, but in the end I went with the simplest solution and just mounted it to the side of the power supply.

The Motor Controller has 4 mounting holes but the power supply case didn't have any good mounting holes so on the inside of the power supply case I add two strips of Sintra for the screws to anchor into.

Of course I also used plastic standoffs so the motor controller wouldn't short circuit on the metal case beneath it.




Step 5: Creating the Custom Back Plate

This Particular UPS has a back panel that can be removed, by undoing a couple of screws. This made it pretty easy to measure and cut a piece of Sintra for the new back panel.

I first cut it to size and attached it to the existing back panel, then checked to make sure I had it the right size for the case to fit properly. I did have to trim the corners to fit the bent metal corners of the case.

I then laid out all of the components that needed to attach to the back panel, and traced there locations. Once I had my lay out finished I could see that I wasn't going to be able to use the existing holes. I used a grinder (for lack of having a better tool available) and removed the inner part of the existing back panel.

With the metal cut out of the way and the new back panel in place I made the openings necessary to fit the connectors. The round holes I drilled with a Step Drill (if you don’t have one GET ONE) the square holes I cut with a razor blade.

Step 6: Wiring

There really isn't much to the wiring; all you are really doing is adding the connector’s inline to the motor wires, and adding a switch to the AC power cord.

I used the power cord from the UPS and also used the original grommet to secure it.  I drilled a big enough hole in the new back plate to install it.  Once in place I ran the ground wire and the White wire to their appropriate terminals on the new power supply.  
Then I added a longer lead to the black cable so it could connect to the front power switch.   I then ran the other lead from the switch back to the corresponding terminal on the power supply, completing the circuit.

I first labeled the motor wires, 1,2 and 3 and then cut about 10" off the end to wire the inside of the enclosure.  I soldered the ends to the female connectors on the inside of the back plate and then connected the existing green pin connectors which connect to the motor controller.

The only thing left was to add the male connectors on to the wires connected to the motors.





Step 7: Finished!

I love it when a project comes together! Now my motor controller is safe, cool and quiet. It’s also nice to have a power switch to turn it on and off, instead of having to unplug it each time.

As future add-ons; I plan on putting some decals on it so someone doesn't make the mistake of thinking it's a UPS. I want to also add an emergency halt button on the top of it, and possibly incorporate spindle control into the back panel, using the original plug as the power connector.