[funford]

Sorry to ask such a simple question but I'm trying to cover all my basis. I have a new to me CNC mill with unknown history. It has a transformer that needs to be wired based on input voltage. It was setup for 208 single, and mine is coming in at 249. I'm asking this cause I'm getting some weird voltage readings throughout the cabinet where I feel I should be getting 120. The following diagram is how I have it wired and what the output voltages are. Why is the reading from E-OV 99? shouldn't it be 0? I'm seeing these half voltages throughout the cabinet. Funny thing is most of the machine is working. I'm trouble shooting a spindle issues and I need to take this transformer off the list.


Thanks.

[machinehop5]

...What about the Interconnects..can't see them in the photo. 208v input would have had a H4 to H10 jumper..Did you remove it..?

[funford]

There is two jumpers both the dark and light green in the first photo.

[funford]

Ohh the actual wires have been removed and replaced with drawn, so its easier to see.

[machinehop5]

There is two jumpers both the dark and light green in the first photo.

...your drawing looks correct for 240v.

[funford]

Are the output measurements correct? Is E to Ov suppose to have voltage? I thought ov was neutral and e was earth ground. But have know idea if a transformer like this is suppose to read such.

[Jim Dawson]

If you are measuring from the terminal to earth ground (E) or cabinet ground, you may get some erroneous readings. You need to measure leg to leg. The leg to leg output voltages are what I would expect, 42 and 122