I picked up a heck of a deal on a vane type air compressor from a buddy who deals in gov auctions. It mates end to end to a large electric motor. Did some searching online and found the specs on it. Its a 2hp motor and the compressor puts out 6.7cfm at 100psi, and 5cfm at 150psi. Is this going to be worth a crap for me? Ill be using a 60gal tank and various air tools anything from paint gun to air grinders and more. Will it be able to keep up?

I was talking to a buddy at work about it and mentioned it had 3 voltages listed on the tag of the motor. 208/330/460 making it a 3 phase. I know most 220 compressors are 2 phase, am I going to be able to rig this up on a normal home circut? Or is this an industrial only deal?

Any info/help would be greatly apreciated.

Kyle

You'll have to get a convertor to run three phase on your single phase power. I've never seen anyone even be able to get 3 phase service at a residential location.

So sounds like I need to maybe find another motor, that sucks. Back to work I suppose.

Thanks.

Just because the motor can run on multiple voltages does not mean that it is a 3 phase motor. 3 phase refers to the number of hot legs carrieing the AC voltage sine wave. The motor plate should list whether it is a single or three phase motor. Does the motor have any capacitors on it? They will look like oblong humps under sheet metal covers attached to the case of the motor. If not, it is almost certainly a three phase motor, if it does have capacitors, it is almost certainly a single phase motor. Search the internet for "static phase converter" it is pretty cheap to build a converter to start one lone 3 phase motor of sigle phase power in your shop. I built a 10hp rotary phase converter w/ 220--->440 step up transformer to run my big 3 phase mill, and I spent less than $300 on all the parts to do it by buying surplus crap.

Later,
Jason

It says on the tag that is a 3 phase motor. Ill start researching and see what I can come up with to run this thing. If I have to spend a few hundred thats fine as I got this free as payback for helping a buddy out.

Kyle

Why spend so much? You can get a 4hp single phase motor for <$80. With such a small motor there's no reason to keep the 3 phase.

Didnt know a motor would be that cheap. Ill also have to look into that as well. Where would be a good place to do some motor shopping?

Kyle

There's no telling what the motor will cost. Don't use that $80 as a barometer, and be disappointed when it doesn't come in at that.


The construction of the motor, the chassis, and several other things factor into price. I buy and install a lot of motors, and I'd never pull a number out of my ass like that. :laughing:

Call a real motor shop (hit the yellow pages for electric motor, winding and armature), and talk to them. You may want to bring that other motor with you to show to them, and see what they've got, and what they can do for you. Some shops might even give you credit back for the motor you bring in, if it's something they can freshen up and re-sell.


You could also luck out, and have it be a common chassis configuration that you could find at WW Grainger or something.

I didn't say it would bolt up to it...but with some creativity anything can work. It's not like it's hard to find a motor of that size for less than $100...

Does the pump you have look anything like this? http://www.govliquidation.com/aucimg/photos/3253/3252860.jpg

Take the cage off of the coupler and see how it's coupled together. To find the same motor would probably cost quite a bit, but you could make anything work. Or, you could buy the same thing (whole compressor) in single phase for almost nothing from a gov auction site...

You may have trouble starting the compressor with a single phase motor of the same size. A capacitor start induction motor (your typical off the shelf single phase compressor motor) typically does not have nearly as much HP when it is trying to start.

I bought an old 3phase 40 gallon air compressor with a 1hp motor on it, I swapped the motor for a 1hp single phase GE motor, it wouldn't start the compressor with the tank empty. Swapped it for a 3hp GE single phase, it would run the compressor until the tank was full, but couldn't restart when the pressure switch kicked back in and there was back pressure on the compressor head. I finally purchased a 5hp GE single phase motor, and it has no trouble with it.

I picked up a heck of a deal on a vane type air compressor from a buddy who deals in gov auctions. It mates end to end to a large electric motor. Did some searching online and found the specs on it. Its a 2hp motor and the compressor puts out 6.7cfm at 100psi, and 5cfm at 150psi. Is this going to be worth a crap for me? Ill be using a 60gal tank and various air tools anything from paint gun to air grinders and more. Will it be able to keep up?

I was talking to a buddy at work about it and mentioned it had 3 voltages listed on the tag of the motor. 208/330/460 making it a 3 phase. I know most 220 compressors are 2 phase, am I going to be able to rig this up on a normal home circut? Or is this an industrial only deal?

Any info/help would be greatly apreciated.

KyleI wouldn't have bought that one.

1) For air drivers (impact and ratchet) you'll be ok unless you're some kind of "God's gift to wrenching" and you and work so fast you never stop to think. It would work for me.
2) For HVLP it might keep up.
3) For grinders or air sanders it is under powered. It will work but you'll have to stop and let it keep up. Having said that, I don't like grinders or air sanders as much as their electric counterparts.

220 compressors are single phase but that's not important here. You have a three phase motor and if you're using it at home you have single phase power. You can buy a phase converter for around $500-$800 but that sort of ruins the deal you got on the compressor. The good news is that if you get a good one it opens the door to lots of cheap 3 phase equipment. You would be surprised how much industrial equipment sells for a song because most people don't have phase converters. If you don't see more 3 phase stuff in your future just get a new motor and you'll be in good shape. Note the RPM and direction that the old motor spins and buy a nice replacement. Does the label tell you how many amps it pulls at 208v? If you exceed that you'll be in the right ballpark for a good motor. Also, get a continuous duty motor. It's a tool and you don't want to have to worry about babying it since it works like a power source.

Ill charge the batteries up in the camera, drag the whole shabang out and take detailed pix.

Kyle

You may have trouble starting the compressor with a single phase motor of the same size. A capacitor start induction motor (your typical off the shelf single phase compressor motor) typically does not have nearly as much HP when it is trying to start.

I bought an old 3phase 40 gallon air compressor with a 1hp motor on it, I swapped the motor for a 1hp single phase GE motor, it wouldn't start the compressor with the tank empty. Swapped it for a 3hp GE single phase, it would run the compressor until the tank was full, but couldn't restart when the pressure switch kicked back in and there was back pressure on the compressor head. I finally purchased a 5hp GE single phase motor, and it has no trouble with it.

This is true and also why I suggested a 4hp motor. And, did your compressor have an unloader on it? Could have possibly helped..

This is true and also why I suggested a 4hp motor. And, did your compressor have an unloader on it? Could have possibly helped..

Sorry that we are getting so far off topic, but yes, the compressor had an unloader. That does indeed help, but it basically just gives the compressor a head start on spinning up to speed, after it charges the 2 foot of line or so, it still has to overcome the tank pressure to open the 1 way valve in the unloader.