Did you look closely at the close up pic, on the right hand side, in the middle of the label, it says "Polyphase rating" with "200/230 VAC 7.5 hp" and below that rating, it says "380, 460, 575 VAC 10 hp" and below that, it says "600 volts Max."
Just want to make sure that you saw that before we go any further... when I first looked at it, I thought it was a 120 volt box, but then noticed everything I just listed above.
I hope "polyphase" is not a fancy word for three phase...
The three things I am trying to gain is longer life of the pressure start up and shut off switch, since it really isn't made for routing that much current through itself. It technically should be set up as a relay to switch on a contact starter.
Some of the reviews that I read off site at various places stated that they have had to replace the pressure switch due to failure from excess current. (or so they say)
I noticed that all of the top end compressors have control boxes on them, with a starter switch and a pressure switch wired to it. There must be a good reason for that.
Other reason is so I can switch it on and off from the other side of the barn, without going to the breaker box.
Also, I have heard these contact starters can prolong the life of an electric motor. Just another thing I read.
Correct me if I missed something and/or if some of the stuff I read is really BS or not.
The switch/contact box has three big screws on top and on the bottom, and the two 120 volt screws that I assume you are referring to.
From the label, it's a 8736 class contact switch. I did find some diagrams, but still cannot really figure out which motor mine falls under. Is it a capacitor start, or this, or that? There were several ways to rig the thing up.
The diagram for this box is on page 75, and probably goes onto the next page...
http://ecatalog.squared.com/pubs/Machine Control/0140CT9201.pdf