First thing I'd have asked for is a picture of the nameplate on the motor, and a picture of the plug that goes into the wall outlet.

All that was shown in the pics already is just useless BS to me.

If I had to guess, I'd agree either someone has a 208/220/230/240 volt motor wired up to plug into a standard 110/120 outlet. OR someone installed a 120 volt motor, it can't power the compressor and trips off.

 

Heres an example.

 

nah, its a 110volt motor. You just need a bigger circuit. If it was a 220volt motor both leads would be ran through the OL circuit. That and the wiring is factory wiring. No factory would use a white lead for anything other than a nuetral wire.

 

Ok cool. So all I need to do is find a standard 110volt wall outlet that uses a 30amp circuit breaker.

 

well, no. To run a 30 amp breaker, you need to at least run #10 wire to the receptacle. That and it needs to be a dedicated circuit. More than likey it is #12 right now if its just a standard circuit. You can do it one of two ways. You can either pull a whole new circuit and wire for this thing, or you can swap the motor out for a dual voltage unit and run it off a 220volt source if you have it. I dont know what kind of situation your working with. Do you have a subpanel in the garage? I still dont like the fact there is no wiring diagram and they are switching the neutral. I mean, looking at the picture of the switch, it SHOULD be 220 volts. But looking at the motor I think its a 110 volt motor. Can you not go over there and check how it was hooked up. All you would need to look at is the breaker feeding it to tell you real quick.

 

Look, can you give info thats useful?
In this pic to the right you can see what looks like a nameplate on the motor. Please, take a pic of this. Then take a pic of the end of the cord that goes into the wall.

 

You can't assume voltage by wire color. This pic shows a universal appliance cord (the tan one) connected by an owner, the black and white wires are universal machine wire (I forgot the name of it) it too is basically universal, you can buy it by the foot at home depot, etc. In this pic it just connects the motor to the cutoff switch.

I'm just using the mentality that you never assume anything when it comes to wiring like this and electrical safety.

 

http://i67.photobucket.com/albums/h2...ictures012.jpg
http://i67.photobucket.com/albums/h2...ictures015.jpg
http://i67.photobucket.com/albums/h2...ictures016.jpg

 

See what I mean?
It clearly says 208/230 volts and it clearly has a 120 volt plug.
All that for this. You need a 240 volt appliance cord or the proper wire, fittings and flexible conduit. And you need to have a 240 volt outlet installed to plug it into.
Those pics make it real easy, thanks for posting them.

 

Heres my set up. I got some wire, sealtite conduit, and the male/ female plugs from work and home depot. You can see the wall plug in the background with the welder plugged in, Lucky for me my main panel is in the garage so I just ran a new breaker, maybe 8" of wire, and a cut in box mounted to a stud. All done without any drywall work.

Hope yours turns out this easy, good luck and be careful.

 

well, I stand corrected. The universal wire you speak of is called SO cable, or SJO cable. I realize you cant just go by wire colors on things like this, but to me that looks like factory wire. Most factories try to stick to wiring coloring codes but oh well. Im happy its taken care of.

 

I was just talking to my grandfather who wired up my house. Were going to run a 240v outlet out of the subpanel in my garage and re-wire the compressor for the 240v plug. Thanks a lot guys for clearing this up.

I still wonder how this compressor ran with how it is now

 

Go check out where it was running. The motor draws 15 amps at 208/230 volts, they for some odd reason put a 110 volt cord on it and was probably tripping breakers like you were.

A 230 volt motor running on 120 volts will draw approx twice the amperage. So they probably stuck in a higher amp breaker and ran the risk of burning the place down.

I know a lot of people who have 240 volt airconditioning blowers set up as shop fans and running off 120 volts. But these draw approx 2 to 5 amps at 240 volts so they work with a standard 15-20 amp 120 circuit.

The worst thing that could have happened (well not the worst) is the plug burning.
I reached out to unplug a 240 volt appliance cord once and was informed by the customer to watch out for the bare spot on that burned up plug, this was at the point when my hand was about 4" away from grabbing ahold of it.

 

I'm going to go out on a limb here and say that they probably have a 120V receptacle wired for 230V.

 

dont feel bad. When I moved into my house, my whole garage was hooked up on an 80 breaker. The problem with this is that the garage is about 100 foot away, and the wire they used was #10 well pump wiring. It was just strung along the attic and feeding an old knife edge disconnect with no fuses in it. Coming off that were a dryer outlet, and all the outlets and lights in the garage.

 

Your motor is clearly marked 230 volts.

Change the plug on the end of your cord to a 20 amp 230 volt plug.

Wire as I suggested earlier with 12/2 w/ground wire to a 20 amp 230 volt breaker in your panel.

 

That would work. The plug that looks like a 120 plug but with one blade turned (kind of). If you have a 120v recepticle you can do away with and it has heavy enough wire it can be converted to a single 20a 230 volt.
You'll need to turn that white into a hot leg.

We used to do this a lot when people bought window AC units and didn't realize they were 230 and didn't have a 230 outlet in the living room.

Looks like the op and his grandfather should have this thing up and running by the weekend or sooner

 

We got it running today
Installed a 240v oulet and re-wired the compressor. Started up right away, where as before it took a few seconds to get up to full speed.

I went to drain the tank and the petcock wasn't draining at all. Unthreaded the whole petcock and rusty-looking water came pouring out! Probably half a liter of crap came out. Then I took the fitting off the top and poured buckets of water in the tank and had the shopvac at the bottom sucking up so much dirty *** water. I don't think anyone ever drained this thing.
I just ordered a new transfer hose and check valve cause mine was leaking from a kink and the check valve ball fell in the tank

All things considered, I still only paid about $100 in some parts and the compressor was free... not bad. Well thanks again guys.

 

I thought that was what it was so good deal on your part now you can buy more tools.