No, not using a VFD, that would be too easy...  Has anyone used Mach to control their Hardinge (well, I have a Feeler FSM-59, a Hardinge DV-59 clone) mechanical VSD in Mach?

I have a QRB1134 retrosensor pointed at the spindle handwheel, one half of which I painted white to give 1 pulse per revolution.  The sensor is feeding a Tachulator digital tach, but I can pull off the 1 PPR signal to feed back to the PC.

Controlling the VSD would involve acutating "higher" or "lower" solid-state relays to run the speed change motor forwards or backwards until the spindle pulse was at the correct frequency.  I'm a stepper-using guy myself, so I have no idea how this would be implemented in the software.

Just a "wonder if" idea for now... My lathe is a 3-phase, and I have a TECO FM-50 VFD generating the 60Hz 3-phase from 208V 1-phase input.  If I were to install a VFD-rated spindle motor ($$$) I'd need to also replace the coolant pump (more $)

Thanks,

Randy

I dont think it would work out very well, I think there would be too much delay with relays and motors and feedback to be able to settle at a speed.
 Maybe fitting a stepper instead of the speed change motor would work. You could set it up as an axis and have your spindle speed macro send it so many steps for a given speed.
Hood

Thanks for the reply, Hood.  I will leave the setup as is.  I'm not sure that a stepper axis would work, becasue there seems to be hysteresis in the speed-control system due to the way it operates (split-pulley) and changing up to a given speed and changing down to the same speed would probably have different positions.

Best regards,

Randy