CFM in Compressors with 1HP Motor

Do what I did with an old recip, Take the head off, and measure the bore and stroke. From that you calculate displacement. Measure the drive and driven pulleys to find compressor speed. Speed and rpm will give a close result in volume per minute.

There is a few perccent of loss, but you should be close enough to find that lynlynch is correct. 1 HP does not have power to run tooling for any length of time.

It's worth noting that efficiency goes down as pressure goes up. In Lynn's compressor, the SCFM (the amount of air, at standard pressure moved by the compressor) drops significantly even with the small difference between 90 and 100 psi.

Also worth noting is that the HP quoted is often from the advertising department, not the engineering department. In Lynn's case, the HP is really about 4amps x 120 v x 80% motor efficiency = 384 watts = .5 hp.

This misquoting of hp figures gets especially nonsensical with shop vacs. A vac drawing 5 amps is likely to be called 2.5 hp. Such a motor might be able to tolerate a 4:1 overload briefly, but there is no realistic way to overload a shop vac, unless it is actually pumping water through the impeller (and thus out the exhaust, rather than into the tank, which is impossible with most vacs).

So if the motor in the compressor in question is really 1 hp (making it a fairly large heavy thing) then the compressor in question might be able to pump about twice as much air as Lynn's.

Still, however, too small to do much work.

displacement of compressor X rpm's of compressor

CFM is the acronym for Cubic Feet per Minute. A compressor is said to have so many cubic feet of compressed air per minute (CFM) of flow from its discharge port.