How to control a Spindle on CNC Mill

[Project5]

I have a Tree CNC mill that I want to retrofit with mach 3 control. I have a question concerning the spindle motor control. The CNC Mill contains an AC servo motor. Is it possible to control it using a VFD? I am asking so because I know that such retrofits normally use VFD. I also have a Fanuc spindle drive which came with the machine but I am not sure whether I should keep it because I don’t know how the Fanuc would fit into the control. How do I control the spindle?

[immortallove]

Does the spindle/servo accept ±10 vdc? If It does, then it requires a PWM to analogue converter for Mach.