Hypertherm has two different 30 amp output air plasma cutting systems. The Powermax30 XP does not have an onboard compressor, the Powermax30 Air does have an onboard compressor.
-30 XP is severance rated (operating at 230 volts) for severing 5/8" steel, and production rated for 3/8" steel. When you operate on 120 volts it is downgraded a bit from those specs. You can operate it off any compressor that can produce 90 psi air pressure, the flow rating is 4.5 scfm @ 90 psi.....if your compressor can only produce 2.0 scfm @ 90 psi you can still cut, but when the compressor drops below 90 he plasma will shut off and give you a low air pressure indication. I have used a small nail gun style compressor (2.9 scfm) in the field and would get about 45 seconds of cut before I had to wait for the compressor to build pressure.
-30 AIR is severance rated at 5/8" )operating on 230 volts), but expect it to cut a fair amount slower than the 30 XP.....this is because the power supply has to share input power with the compressor. Production rating is at 5/16" on 230 volt input and is downgraded a bit when running on 120 volt power. You need a full 20 amp circuit (nothing else plugged in) when cutting on 5/16" steel, though you can turn down the cutting power and run on a 15 amp circuit if only cutting thin gauge material (say cutting up some old roofing.) We have a lot of 30 Air units in the field, we do not seem to have any issues with compressors. The compressor is a high efficiency active automotive suspension unit...very reliable. To make the compressor more effective and more reliable we designed a special low flow, low pressure torch that allows for a more efficient lower pressure compressor....this is what other plasma systems with onboard compressors do not have!
The 30 air has less cutting power than the 30 XP, the 30 Air costs more than the 30 XP. (the 30 Air has a compressor, adds cost and uses power!)
If it was me, and I was going to use the plasma a lot, especially in the shop....I would use the money I saved buying the 30 XP and would apply it to a compressor. However if I always needed a plasma on my truck to dismantle things in the field where there was power but no compressed air.....then the extra cost of the 30 Air would be my choice. We sell about the same number of each. There is a noticeable cut power/speed advantage with the 30 XP.
They are completely different units and different torch and consumable designs....each designed for specific use! Jim Colt Hypertherm