Hi,
So I have decided now to go for the PWM Spindle control, one question solved

Semi-OFF Topic:
However, I do not know if anyone can help with this:
My Spindle controller has 4 operating modes, and I do not know which one to choose, as tech. manual does not describe the exact differences of these modes:
-Mode for Constant Torque applications
-Mode for Variable Torque applications
-Mode for Constant Torque applications with sensorless flux vector control
-Mode for Variable Torque applications with Energy saving
This is a TELEMECHANIQUE Dirve, ALIVTAR series...
ANyone has an idea, or at least whom to ask? (Or should I try to contact manufacturer? but it is an old model)
*** GOt some info, spindles should be constant torque application... ***