Actually My biggest air use is a Powermax85 plasma....it has internal air regulation....and as long as the inlet is between 180 and 135 (lower and the internal pressure sensor will shut off the arc and send an error....higher and the internal coalescing filter is prone to fail) I do not have issues. I have run with a 90 to 120 psi cycle on a smaller compressor for over 30 years with no issues....so I'll stay with that!

I do point out that on a tool like a plasma cutter...that needs at least a minimum inlet pressure under flowing conditions, be sure to install a good quality pressure gauge right at the inlet for monitoring/troubleshooting purposes. The pressure back at your compressor will always be higher than that directly at the tool inlet when air is flowing.

Jim Colt


Quote Originally Posted by GlenC View Post
Jim, nice find!
You mentioned setting the pressure switch to 90psi... You really don't want to do that. Most tools are designed to run at 90psi, if you are using a sander or any tool and the compressor kicks in at 90psi, you will most likely drop below 90psi during use, reducing performance.
For a shop system, 100/135-145 for single stage and 110/165-175 for two stage should work well. Two stage installations usually have lower cfm and can use more room to stay ahead of usage.

Funny thing, I have a Atlas Copco 5HP two stage direct drive 175psi and have been thinking I should have gotten a higher volume single stage....