Garageineering the Central Pneumatic Compressor #66399

I bought this little 12 volt DC high-volume compressor because it appeared to be the best of it's breed as researched on 4X4 off-road boards. It's impressive, with good associated hardware including a coiled hose and decent pressure gage, and packaged in a fine ballistic nylon satchel.

It generates a fair amount of heat in the compressor-head, though, and I noted that it would never run very long before it cut out, and after cutting out, you were done for at least an hour before it would start again. Very annoying, since the finned compressor head cooled down in 10 minutes, but the heavy motor stayed warm longer, and I suspected that the overheat device was attached to the motor, not the compressor head.

The obvious problem was that the fitted heat-switch was either:

• Installed in the wrong location
• Installed with too low a re-open rating
• Installed with too low a close-rating

So, the garageineering project was to remove the offending heat switch.

Step One: find a manual with a wiring schematic with a proper color code for the wiring. Step One was rejected as a no-can-do. I quickly found MY manual, no schematic in there, then it took maybe 10 minutes of Internet research to whistle up a "master manual", but it had no wiring schematic, either. I assign guilt for that to Company Lawyers. Here's the two pages required from the op-manual:

Download Scanned-image-2

Step Two: using the re-printed, embiggened parts drawing in the manual, I began to disassemble this suckah. This required the use of my Craftsman quarter-inch, metric socket set. Lots of little partz, but it came apart logically. I removed the control-cap  end of the very-moosey 12vdc motor and noted the usual two-pole DC setup with switch and inline blade fuse. I noted a little round device with two poles and a blue wire leading into the motor enclosure. On the partz diagram, this was the #18 "Temperature Controler" (sic). I demounted it's tiny Phillips-head, less-than-#0 screws, pulled it from it's hole, and snipped it's leads close to the device. Stripping the remaining two wires and applying a Wire Nut, I checked everything for fitment in the cover, then re-assembled the unit. Time of project so far: 45 minutes.

In the garage, I had a 10-gallon air-tank reading no pressure. It took three operating sessions of about 3 minutes each, with 15-minute cooling rest, to blow the tank up to 90#.

Now I have a useful, compressor, thinks meself, but to make sure, I deflated the spare on my Little Black Truck and re-inflated it to 45# in one 3-minute session with the CP #66399. 

Note that I have "un-lawyered" the device, and somewhat un-engineered it as well, but it was "over-lawyered" and over-engineered for heat protection. I am the only one who will use this equipment, or if I loan it, I will instruct the borrower that it lacks an overheat shut-off and not to run it more than 3 minutes continuously.

Further modification: I'm considering finding a round sleeve that will just cover the compressor head, and hooking a 12-volt marine Bilge Blower to it to provide additional cooling. That will cost another $40 or so, but then I will have a continuous-duty-capable 12-volt compressor.

Comments

[Richard Bergerson]

I love your attitude. If I have something that doesn't work or doesn't work rightfully, I may as well tear it apart and see if I can fix it. If I destroy it, no harm done, it was already garbage. (Absolutely HATE fragile plastic parts.) I just wish we could do the same with our government that isn't working.

[Will]

The drawings in that manual aren't real clear, so I'll just give a general advisory. Ventilate as much of the unit as possible. In other words, swiss cheese it. With my little boxy 12v emergency compressor, I've pumped up the tank on a 2hp compressor (I let the smoke out somehow, and hadn't found a replacement then) in one run. The housing looks like Cheney mistook it for a lawyer.
I like your idea of forced air cooling it, but getting air moving through taht electric motor would be a big plus. Two fans? I'm thinking some of those little flat muffin type fans that are used on some electronic boards in computers might be ok. Some of them are 12v. Might find a selection at electronic swap meets and recycle stores.