Air compressor hp

[yukon cornelius]

I have a air compressor that is 1940-50s vintage. When relocating it I found the wiring was very bad and the insulation was falling off where it goes into the motor and not very replaceable. I am having a hard time putting a minimum of $150 plus shipping towards a replacement motor for such an old piece of equipment that is not ideal due to its slow recovery. It currently has a 1.5 HP motor. I have a 1 HP with the same rpm. Do you guys think it would run it or is it a waste of time to swap it out?

[millwright]

You can always go a little smaller on the drive pulley, it would slow it down some but should give you a little more power

[21incher]

The HP on compressors is not always properly stated. Look at the amp draw on both motors first to see how close they are. I am running a 3 hp rated compressor pump fron harbor freight with a old 1 HP motor in my wood shop and as stated before I just used the smallest pulley I could find on the motor. A little less air output, but it works. 

[gww]

I had an old sears model that the 240 volt motor burnt out on.  I took a 110 motor out or a treadmill (they are everywhere and cheap) and put it on the compresser.  It now runs half speed which makes it really slow but it takes care of my needs.  I also have an easier time using it when moved due to the 110 volt and not needing a special plug.  It is slow but I have used it with a roofing nailer, my brad staple nailer and to blow the dust out of my garage or off of me.  It is slow but was very cheap (free).  Just something to think on. 
gww

[yukon cornelius]

21incher, thanks! I never thought of checking amp draw. They are the same. The old motor is OLD and at least double the size. I am going to give it a shot.

[21incher]

I think that a 1 hp motor draws 16 amps at 115 volts so If they are close it should work. Most 1hp motors are continuous duty and cap start, but you may want to check that also. Make sure that the unloader valve is functioning properly also. I recently replaced one of those big old motors on my 1950 south bend lathe and the scrap price of the copper windings from it almost 1/2 paid for the new motor.

[Kbeitz]

Very easy to fix your old motor...
It's called liquid electrical tape.
Just center your wires and brush it on.



 

[yukon cornelius]

That was considered. even a winding spray on protector I found. the problem was I could not be certain I could get all of it covered and as far back as I could see was losing its coating. I considered also pulling new wires to the brushes but cant get to all of them. I have said before my cousin was electrocuted from an old tool. I will take no unnecessary risk. i have just lost my sense of adventure for such.  ;D

[beenthere]

Yukon
Protect yourself with some ground fault circuit interrupters (GFCI). Then you cannot get shocked.

http://www.thisoldhouse.com/toh/article/0,,249536,00.html

[r.man]

Any motor swap should be followed by an amp test at load. I once gave a spare blower fan motor to a friend, he swapped it but phoned to say that it would only run for about 5 minutes and then would have to cool off. He had used the adjustable pulley that was on it and adjusted for it's former load. Rated at around 6 amps it was pulling 18.  With a few turns of adjustment it was within specs and lasted for years. For almost any load a smaller or different rpm motor should work if the pulleys are sized to keep its amperage within specs.

[yukon cornelius]

Update, I bought a new 2hp from harbor freight $120ish with a coupon. $20 pulley from grizzly and its up and going again. How nice it is to be back to having a supply of air. Now what is next to fix??? 8)