View Full Version : Bridgeport Mill and three phase high leg

04-27-2005, 03:14 AM
I'm wiring my BP Series 1 CNC mill in it's new home. Should I be concerned which terminal has the high leg? Will it affect the power outlets for the lamps or any of the control electronics?

I'd hate for any of its smoke to get out.



Jim Hubbell
04-27-2005, 03:22 AM
Yes, if in fact you have a "high leg" do not connect it to the phase which feeds 120V lamps, or any thing requiring 120V. If your system is 208V 3 phase there is no "hi leg".

04-27-2005, 08:44 AM
If you are running a RPC, yes, make sure the single phase internal 480/220/to 120 volt transformer is across the "line" legs and not the generated ones.

The large transformer in the back cabinet powers all the 120 on your machine.
Looking at the fused dissconnect you can see the difference in wires laid down on the bottom screws. My transformer was on the outside legs. But with all the factory errors in my machine that don't mean yours will be.

Mine has no errors now. I found probably a dozen wires in my machine with different numbers on each end. (I reused a lot of the wiring)

If I can be of more help send me a plane ticket. Carrol if jetting off to Oregon. PS, I like beer and barbeque..

David http://bbs.homeshopmachinist.net//biggrin.gif

04-27-2005, 12:59 PM
Thanks Dave,

Having you out here would be great! Barbeque, Beer, Babes, Bikes, Boats, and Bridgeports!
Unfortunately, I threw the switch and tested my outlets and everything worked out. But if you ever are in the area, look me up. The guys I'm sharing shop with are great bike collectors and builders and machinists/hobbiests. You'd fit right in.

I wasn't able to trace the outlets to the line terminals so I figured that there must be a contactor open in between, or that the outlets must be driven off of some secondaries of the three phase transformer, which would prevent the high leg problem. I'm still not certain, but I am up and running.

Thanks Dave,


04-27-2005, 01:24 PM
Fuses for Lamp outlets are ... Inside left hand box, with red wire? going to them. On the left rear the outlets are ran by the Opto-22 cube and circuit card. One is oiler, coolmist and then mine had a "extra outlet" wired in with Romex.. Yep.. romex. Gone now.

Yours still making you parts as is?