So as far as I can understand it, the power comes from the wall, through the cord to what I call a contactor (I've replaced them on center pivots and I'm just always careful to wire them up exactly the same as it was before I got to it ). So what is the need for the green wire at all? When does current flow through the green wire? Also, how does this reversing polarity not reverse the direction of the motor? I thought when the black wire was hot the white wire completed the circuit and when the white wire was hot the black wire completed the circuit. Already we bump up against my limited understanding. My understanding of 220 is that the black wire is hot half the time, the white wire is hot the other half of the time and the green wire is ground. Is this OK? I guess I'll keep calling it 220 ) coming from the wall. I think I'll explain how I think it works so those of you who are knowledgeable will correct what I don't understand.įirst of all you've got just regular old 220 volts (or is it 240? I seem to remember putting a voltmeter between the two legs and actually getting something like 246. Wiring this thing up is really exposing my ignorance on AC stuff. So I got a motor (5 HP single phase ), compressor, magnetic starter with thermal overload and a pressure switch from North Central Air in Downs, KS. Recently I decided to go ahead and put a compressor and motor on it. I had an 80 gallon vertical tank that I was just using as sort of a buffer air supply. I'm pretty dense when it comes to AC wiring so please bear with me. Posted 14:35 (#3057448) Subject: Wiring a magnetic starter with thermal overload protection Wiring a magnetic starter with thermal overload protection

220 volt pressure switch wiring