> As far as starting torque, before a decent-sized compressor is up
> to speed,
> you'd need a doggone large accumulator or else need to run unloaded a few
> revolutions (which is what lots of better compressors in this
> range in fact
> do - centrifugal unloader) to alleviate most of the starting load. No
> realistic amount of longer pipe, etc. between the compressor and
> tank would
> do much there.
Not sure I understand your thinking here, Karl. A quick check of HF's web
site turned up a compressor pump rated 5 hp, 145 psi, with a displacement of
20.5 cfm @ 1370 rpm or .015 cf/rev. If we scale that back to a 1hp unit,
displacement would be .003 cf/rev or about 5 cubic inches. 3/4" copper
tubing has a cross sectional area of about 0.3sqin, so a 1.5 ft section
would provide about a displacement's worth of buffer. So, at the end of one
revolution, the pressure would only be about 15 psi or about 10% of full
load. Two revolutions gets us 20% and so on.
And if you double the length of pipe, still only 3' of 3/4" tubing, you
double the time to full load, etc. Heck, if you wanted to, you could even
tee a smaller pressure vessel into the existing line ... something to do
with those propane tanks you've been saving <g> Granted this would waste
some power at every startup, but so would an unloader.
Seems to me an unloader wouldn't be that hard to add either ... wire a
solenoid to the existing start switch inside the motor. A suitable solenoid
should be only about $10 on eBay ... in fact there's a lot of two new ones
closing without a bid at $15 in about 15 minutes.
Randall
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