[jd@apm]

I'm installing 2 cnc machines. 1 mill, 1 lathe, both 3 phase, both have built-in transformers. I have 208V 3-phase in my building. My question is, without having to check proper phasing by trial & error, can I check phasing voltage at the transformer to see if my phasing is properly connected?

[springlakecnc]

Hi
I dont think so. if your spindle motor goes the wrong way, just change any 2 of the 3 electrical legs.
Remember, if the machine has a frequency drive for the spindle, the spindle should always go the correct direction, BUT, the coolant pump may be going the wrong direction, so you would still need to change 2 of the legs.
Good Luck