Hi gperkins,
It seems you have DC Brushed Servo Motors not Stepper motors. I'm guessing you have Aerotech 1135
I would expect you have some kind of encoder feedback also. Do you have specifications on those?
Our KStep only works with Stepper Motors so would not be appropriate.
It seems those motors are rated at 80V @ 5.5A continuous. Our SnapAmp could drive those.
You might be able to use your existing drives which might involve less wiring changes. You would need to research what they are and how they interface. I did a Google search and found this:
https://www.google.com/url?sa=t&rct=...jouLeOlYkZXBPy
HTH