I would imagine those off the shelf motors are relatively cheap, but I do like the idea of variable control. Wonder if the compressor efficiency (from an air-producing standpoint) would decline as rpm dropped? ( more time for leakage as rpm decreases)Seems like it might be more of an issue for rotary compressors vs. piston, but then again as the cups and valves wore I would expect a loss there also.

Sometimes higher rpm can compensate for worn components. For a time, anyway.

"Forget pounds and ounces, I'm figuring displacement!"

If we accept that: MBG(+)FGSF(=)HBG(F1)
And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1)
Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT?
PB answer: It depends.