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Posted

So, after reading the link posted by Rockwood I'm still not sure what the true HP rating of my compressor is and the true CFM output is.

It's a Campbell Hausfeld upright with a 60 gallon tank.

The label says AVG SCFM 10.3 at 90 psi. I don't think it really puts that much air out when I am sandblasting. What does the S in SCFM mean anyhow?

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Posted

Here you go Reg, a calculator for the true HP of an electric motor. The S is standard I believe. I did the calculation for your compressor which is calculated a true 3 hp, which is not bad for a protable, this should be good for a lot of items at 10 cfm at 90 psi, certainly enough for painting with a lot of low cfm guns, and maybe some pressure pot sandblasting, those pesky siphon feed blasters suck a lot of air and are crappy IMHO, I have one so talking from my own experience. Acompressor like yours would be fine for Joe's needs too. Here is the link http://www.onlineconversion.com/motor_horsepower.htm

Posted
OK, so that works out to be 3.137 HP. Gee....maybe I should divide the CFM's by 2 also.

No, that depends on more variables, compressor pump size, single stage,dual stage,output,capacity, tank size, hose size and length.

This calculaotr determines electric motor hp, it does not calculate cfm capacity of compressor pumps.

At 10 cfm on 90 psi, your probably close, don't froget those blasted siphon feed blasters suck a lot of juce, how is your's for spray painting or running a DA sander...Fred

Posted

It works great for those types of tools. While sandblasting though it sort of peters out after a minute or two. Still blasts but not as good. I have found that if I set the pressure at about 80lbs instead of full blast it'll put out a more consistent amount of sand but the compressor does run full time. I wonder how may CFM's you need to run one of the typical lb blaster pots at full bore for an extended period of time?

Posted
It works great for those types of tools. While sandblasting though it sort of peters out after a minute or two. Still blasts but not as good. I have found that if I set the pressure at about 80lbs instead of full blast it'll put out a more consistent amount of sand but the compressor does run full time. I wonder how may CFM's you need to run one of the typical lb blaster pots at full bore for an extended period of time?

Reg, whatever sand blaster you use, it may be wise to run your compressor at 15 minutes on, with a 10 to 15 break, or 20 on 20 off, just to allow this unit to cool down.

To sandblast you probably would do best with a true 5 hp dual stage compressor with a minimum 60 gallon tank with a 15 to 20 cfm output at 100 psi.

Most hobbyists, home shops don't have such an animal, so big sandblasting jobs are tough and tough on the compressor, plus it takes a long time.

In my area we have a Tombstone maker, he custom sandblasts anythings you want up to about 6 ft by 8ft , for a buck a minute, and he gets a lot done in a minute, a typical rim takes him maybe 10 minutes both side, and super nice job. He did my trunk lid inside and out charged my 25 dollars.

Posted
Fred;

Very good link. Should be required reading for all. It says what I have been saying for years.

Walk into any electric motor shop and try and buy a 6 HP motor. There is not such a motor made but Sears and others use the "puff" theory to boost HP ratings way beyond there normal working capabilities. Norm should read the link but my guess is he will not. And he will continue to claim his compressor is 6 HP because the label says so.

You are correct Don. Especially since I have no problems doing the things I have to do with my compressor. Therefore, I am not going to argue with Sears or anyone about the claim that it's a 6 HP motor. If anyone wants to dispute that, it should be done with Sears, not me. No, I did not go to that link because it would be a waste of time for me to do so, due to this.

It's like the color blue. Who named it blue, and is it really blue, or is it green? After all to some that may be color blind, blue may be green. So, is that color blind person really color blind, or was the person who named the color blue color blind? It's all a mute point.

Posted
You are correct Don. Especially since I have no problems doing the things I have to do with my compressor. Therefore' date=' I am not going to argue with Sears or anyone about the claim that it's a 6 HP motor. If anyone wants to dispute that, it should be done with Sears, not me.

It's like the color blue. Who named it blue, and is it really blue, or is it green? After all to some that may be color blind, blue may be green. So, is that color blind person really color blind, or was the person who named the color blue color blind? It's all a mute point.[/quote']

Norm, not sure why these Companies like Sears feel the need to market electric motors they way they do, it's not an accurate picture.

A 5 or 6 hp motor needs a 220 to 240 volt power source, in the area of 30 amp draw at 220 volts, other wise a 6 hp motor on 110 volts would be drawing like 55 to 60 amps, not going to happen.

Case in point, I doubt your compressor or my compressor's motor which are 6 peak hp, have anywhere near the hp,torque,power, as my 6 hp Honda knock off engine, which is a 6 hp engine.

I have a shop vac, says 5 peak hp, like I doubt it.

I really have no issues getting what I need done with my compressor either, but with a DA sander going or a siphon feed sandblaster going it will run nonstop, it will keep up to 90 psi, but runs non-stop. My compressor cuts in at 120 psi and cuts out at 150 psi, I have 6 cfm at 90 psi, and 8 cfm at 40 psi, just enough for some of these air tools, it can run 12 cfm continuous.

These units are good enough for home, but if I was using mine for commercial purposes, it would not happen, I would want a better machine, there great for home, and occasional use, even spray paint with them is not too bad........Fred

Posted

Reg..I have been telling myself when my Camphell Hausfeld goes into the dumper I would get a two phase 80 gallon job-a-do..but till then...V-twin CH is going good..

another thing to watch close on the replacement 5HP motor (so called %hp as they are high torque 56 frame motors) the cheapo starting capacitor is very short lived items...other than that the motors seem fine...

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