Very cool project Mike!
I have access to several treadmill motors and have retrofitted my WEBB mill with a 3hp and KBCC control.
I've just purchased a Supermax CNC mill and I'm going to swap out the spindle drive motor with another 3hp treadmill motor, KB control, but this time I'm looking at their KB signal isolator to be able to control the motor from my Fagor cnc control.
Have you used one of these?....
http://www.kbelectronics.com/catalog...ntrol_prod.htm
The Model KBSI-240D Signal Isolator provides an isolated interface between non-isolated signals and KB motor speed controls. Signal sources include process controllers, transducers, microprocessors and programmable controllers. The maximum output voltage of the KBSI is 10 volts, which is a linear function of the input. The unit is versatile, since a single model accepts a wide range of voltage (0-25, 0-120 and 0-550VDC) and current (1-5, 4-20 and 10-50mA) signals, multi-turn trimpots are provided for Min and Max. The KBSI can be operated from either 115V or 230VAC 50/60Hz.
Dimensions:
2.7" x 4.8" x 1.1".
Models where used:
KBMM
KBIC
KBCC
KBPB
KBPC
KBRG
KBWD