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Old 10-01-2016, 06:56 PM
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Join Date: Feb 2008
Location: Warburg, Alberta, Canada
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Originally Posted by Silverback View Post
Ironman, I totally missed this post and just noticed it:

I think this partially answers my question, you think 5hp will be limited to about 800rpm? Why? How did you do that math? Are you calculating off of the no load or some approximated loaded speed?

If you look in the manual there are pump charts which have horsepower consumed at X rpm and expected output at said rpm.
I used that to figure your max rpm for 5 hp will be between 7-800rpm.
You can exceed the ratings on a motor for a short time and if it has a thermal overload button you are safe.
As most shop work is short periods of running followed by sometimes days of inactivity, you may not smoke it. But having a good supply of air leads to having more air tools.....and sooner or later a small sandblaster, then you're in the shit.

That's why I said "Goody" when I saw your unloader heads, because the motor killer is in starting.
You could use a D-2 governor off a truck...about 10 bucks and let the motor run continuously, and the D-2 will turn the compressor on and off by lifting the intake valves. Then it will probably work on the 900rpm range you are thinking of.
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Even duct tape can't fix stupid ... But it can muffle the sound. Attributed to Red Green
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