PDA

View Full Version : Coleman/Sanborn Wiring Schematic



astroracer
01-03-2006, 09:56 AM
Does anyone have a wiring schematic for a Coleman/Sanborn 7.5hp two-stage 80 gal. air compressor? I have model & serial #’s if that is required.

I purchased the unit used and it came with none of the usual paperwork. It was running just fine before I moved it but, now that I am hooking it up in my shop, the breaker box seems to have a direct short to ground in it. It looks like it is wired correctly so I need a schematic to varify what I have.
Thanks
Mark

CCWKen
01-03-2006, 08:38 PM
Do you have it wired to a 220v breaker?

What color are the leads? Where are they connected?

You probably have the black wire going to common or ground. Does this unit have a starter or just a pressure switch box?

astroracer
01-04-2006, 05:55 AM
<font face="Verdana, Arial" size="2">Originally posted by CCWKen:
Do you have it wired to a 220v breaker?
It is wired through two 110v breakers to a 220v outlet. The outlet reads 110v on either side with 220 indicated across the lugs.

What color are the leads? Where are they connected?
The leads are black and white and they plug into two lugs at the top of the breaker box with a ground lead at the back hooked up with the ground coming from the motor.

You probably have the black wire going to common or ground. Does this unit have a starter or just a pressure switch box?

It has a starter and, as far as we can tell, everything is hooked up correctly. My dad is an electrician retired from GM and he has looked at the wiring and checked it and thinks everything is ok BUT... when we check continuity between the top lugs we have a direct short with NO power to the lower half of the box. The circuit breaker is connected to the top lugs on either side of the box and we have a direct short between the lugs when the breaker is in. This is strange because, like I said in my first post, the compressor was running fine before I moved it and I have NOT dinked around with the internal wiring...
Thanks for your help.
Mark
</font>


[This message has been edited by astroracer (edited 01-04-2006).]

[This message has been edited by astroracer (edited 01-04-2006).]

CCWKen
01-04-2006, 04:57 PM
Holly Smoke! You two guys are scaring me!


<font face="Verdana, Arial" size="2">It is wired through two 110v breakers to a 220v outlet. The outlet reads 110v on either side with 220 indicated across the lugs</font>

First off, pull those two 110 breakers and get a real two-pole 220v 40 or 50A breaker.


<font face="Verdana, Arial" size="2">The leads are black and white and they plug into two lugs at the top of the breaker box with a ground lead at the back hooked up with the ground coming from the motor.</font>

Now you're really scaring me!
Your two black (or one black, one red) feed lines TO the compressor socket should be connected to the circuit breaker lugs in the main panel. Black on one half, another black (or red) on the other half. You should be using at least 8/3 for a short run and 6/3 for runs 25-50ft. DO NOT connect wires to the top buss bar lugs. These are your feed lines TO the main breaker box. You should have a white wire going from the breaker box common buss to the ground of your socket. The socket ground (common) will be the center or round hole. The other two BLADE holes should be connected to black and black (or red).

Wire the plug on your commpressor the same way. If the compressor cord has black, white and green leads, connect the black to a blade terminal and the white to a blade terminal. Connect the green to the common or round terminal.


<font face="Verdana, Arial" size="2">...when we check continuity between the top lugs we have a direct short with NO power to the lower half of the box.</font>

Is this the Main Breaker Box? As already stated, you should not have any wires connected to the mains feed lugs except the large wires that feed the box. Your feed lines to the compressor socket will be connected to the breaker.

With no power to the main box, you may have continuity between the two busses if any appliance, tool or light is pluged in and on. Turn all the breakers in the box OFF as well as the mains feed then check continuity. If you have continuity after that, then you have a short in your main box. (or you have connected or grounded the mains busses.)

I suggest you contact an electrician and have him check the wiring in your main box and the feed for your compressor. It sounds like much of your "in-house" electrician's knowledge is weakening.

astroracer
01-05-2006, 06:04 AM
<font face="Verdana, Arial" size="2">Originally posted by CCWKen:
Holly Smoke! You two guys are scaring me!

Is this the Main Breaker Box?</font>
This is NOT the Main Breaker Box... Sorry about that, I guess I should have clarified, the breaker box I am talking about is ON the compressor. The Main Breaker Box is fine, there are no concerns with the way it was wired. It was wired by a licensed electrician and everything in the main box and out to the compressor outlet checks okay.
I did find a schematic for the compressor. It is a single phase mag start and it looks like everything in the box (on the compressor) is wired correctly. If we can't get it figured out I will get an electrician to look at it.
Thanks
Mark