Message text written by INTERNET:DRSkruffy@aol.com
>OK, I will split a few hairs too. I wasn't even considering oilless
compressors, but I can tell you that the compressors around 500 dollars run
at 3450 and the better ones run at 1725, 1450, or thereabouts. I was told
that is how they can claim 5hp out of them is because they are doubling the
speed.
<
The compressor at the shop is a 10 HP, two stage that delivers about 5
times the air as dos the 5 HP two cylinder (not two stage) one next door.
This compressor has a motor that turns 1700 RPM and although I haven't
measured it, Ill bet the compressor itself runs at less than 1000 RPM with
the belt drive speed reduction. This compressor runs on 208V 3 phase
power. Not your garage type compressor and it cost about four times what
the 5 HP compressor did.
Speed is only part of the equation. Pump displacement is another and the
better compressors use larger displacement pumps and run them more slowly.
This gives better reliability and endurance.
Could it be that the low end manufacturers put a 5 HP motor on their
compressor but load it to where it only produces 2.5 to 3 HP in an attempt
to keep the current down to level compatable with house wiring? In this
way they can advertize "5HP!" without actually producing a compressor that
delivers 5HP worth of air. Just wondering.
Dave
|