Compressor motor

[old]

So I noticed that surplus supply had a good price on a 5 HP compressor motor so I ordered one. Been putting it off far to long and it sure will be nice to have my big compressor back up and running. I do need to buy a new pulley since this one has a 7/8 shaft and the old motor had a 1/2 inch shaft. It will be nice to be able to use air tools again.

 

[Janicholson]

Always nice to have air (compressed) Jim

 

[Patsdeere]

Is there enough meat to drill it out to 7/8"? Then you don't have to even but a pulley.

 

[Mule Meat]

(quoted from post at 12:56:05 04/16/19) Is there enough meat to drill it out to 7/8"? Then you don't have to even but a pulley.

Would not be a problem if the keyway or set screw will not be effected and have enough left to work with. Going from 1/2" to 7/8" bore is a fairly big step.

As cheap as pulleys are I would buy a new one and not have to worry about a modified one would fly apart.
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Be a good idea to compare the RPM speed between the old and new motor. May need to "regear" the pulley ratios to keep the compressors RPM close to factory specs.

Let us know how it works out.

 

[old]

If I remember right both the old and new motor spin at 3250RPM. I ordered a double pulley from surplus supply this afternoon. Should have order it when I ordered the motor but did not think about it at the time. No one local had one plus most I have found local are aluminum which I have found in the past not to hold up. One I ordered is cast iron

 

[John T]

Maybe NOT the new motor you have, but I have seen soooooooooooo many motors with labels such as 5 HP or 5 Max HP etc or all other sorts of hyperbole lol (and far less size and mass then others of the same so called HP) that didn't have anywhere near the power they might lead one to believe grrrrrrrrrrrrrr. Hopefully yours will be fine. It reminds me how some huge old John Deere may have been rated at say 12 HP while the tiny motor in a lawn mower might be much more Im thinkin YEAH RIGHT !!!!!!!!!

Best wishes

John T

 

[Russ from MN]

3250 is a pretty strange RPM! Maybe 3550 or something close to that.

 

[Texasmark1]

When I was a young lad my granddad gave me a ⅓ hp motor.....I was like 10....now what is a 10 year old going to do with a motor in the first place....but it was a kind thought as he was my favorite and my best fishing buddy.

To the point: The motor must weigh 50# and is 12" or so in diameter. He plugged it in and it ran when he gave it to me....last time run 60 or so years ago. Have no earthly idea as to the specs and never used it. Knowing technology and the right kind of components, available today, one can get so much more out of so much less.

Agree on being careful what you expect out of your purchase. After being stung on a split phase bench grinder from a flea market (get what you pay for), I use FLA as my primary guide in motor selection along with starting/running aids for specific applications, like his compressor requirements.

 

[fixerupper]

I learned the deceptive advertised HP trick the hard way when I bought a new Crapsman table saw 25 years ago. It was advertised as 3HP 110V or 220V. I was green and fell to their deception, the 3HP on 110 V should have given the deception away but like i said I was green. It was way wimpy when I tried ripping 2" lumber. Finally I looked at the data plate on the motor and discovered it was 1 1/2 horse going by the amperage draw. Changing it to 220 V made it an acceptable saw now but I have not bought another Craftsman power tool since nor will I ever.

I'm sure Rich knows what he is getting. 3250 RPM sounds about right to me.

 

[old]

3250 is wrong it is 3450RPM as per the surplus supply catalog

 

[old]

Specifications are
5HP def. purpose
volt 208-230
amp 22.5
3450RPMrotatio CCW
45lbs shipping weight