To LD1
I have to make a retraction on my off the top of my head specs. To be exact the cylinder is 4" x 18''. Most people do not read the numbers very close or understand the effect a size change can make. In my orginal post I had actually typed 4" but when I did the math I could not achieve 20 tons. I reverse engineered the formula because I was sure it was 20 tons. I know I have 20 ton bottle jacks because it says so on the label.
I went out to measure on my 4th snow blowing of my drive and the 2nd of the farm lane across the road. Lets put my slip of memory down to Sudden Ground Hog Fever.
Craig Clayton
Definatally not 20 tons then. 4" and 2000psi = ~12.5 tons of force.
But the reasone I was questioning the pump GPM is because along with PSI, GPM is the other factor used to determine HP needed.
There have actually been ALOT of threads in the last year or so about guys wanting to take the 6 or 8 HP motor off their splitter and put on an electric 220v motor and wondering what size they need. Most of the time, it translates into a 5HP motor.
BUT their is a big difference in 5HP motors. There are the motors that only weigh ~40lbs and are a compressor duty that are listed @ 5HP. BUT they really aren't 5HP, especially when they list the FLA at 13 or 15.
And then there are the TRUE 5HP motors. Weigh ~ 130lbs, have a SF of 1.15, and have a FLA of ~21+. These are usually the ones that are needed.
Some people get lucky with the little compressor motors. But motors dont stall easy. They can draw double the FLA and sitll keep working. It just isnt a good Idea and shortens their life expectancy.
And since you initally said yours had a 5" cylinder, a 2HP motor, and was still FAST, something didnt add up.
Using the formula HP required = (gpm x psi) / (1714 x Efficency)
with your high wotking up to about 500PSI, that would give you 5GPM and the low at 2000, that would give you 1.5GPM. Any more than that, and you are probabally over drawing on the motor.
A true 5HP motor is a good match with an 11GPM 2-stage. (which is about 2 GPM on the low speed)