Hi, BWP
You need to be careful some of those machines didn't have a proper "Grounding".
Your spindle motor control is a single phase to 3 phase, Variable Frequency Drive "VFD".
The Board on the door is a Brake Out Board "BOB".
Post the Part Number and other info on the motor control "VFD", I may have a Book on it in a PDF file.
If you live in the US, PM your Phone # (Click on my user name), I'll give you a call, Do you use Skype (Internet Phone)
Chip