So, i enter a whole new domain of eletronic. I am in the need of a VFD to power a lathe spindle motor. Searching for one on ebay i came across the term "Constant Torque" and "Variable Torque" drives. Apperently variable is for fans etc. where "no load" is provided and constant is for compensation for loss of torque due to lets say a turning operation. So far so good.
My question is, how to tell if a VFD is constant or variable torque? More specifically this is what i have in mind: