First off, this place is like a fire hose of knowledge on CNC systems. I've tried to take a small sip a couple times now, and ended up drinking a few gallons! Particular thanks to Al_The_Man.

In my adventure of planning out a motion control system for a benchtop bed mill, I started with the initial plan to go BLDC, and had motors and drives spec'ed in the 750 W range. I was pretty pleased with the price I had landed on per axis (~$550, all new parts), but that was before I started investigating the cost of a DC power supply. It quickly became evident that to contain costs, I would have to build it myself from a 2:1 transformer, rectifiers and capacitors. This scared me off, because of the unknowns and the potential for disaster.

Next, the adventure brought me to AC drives and servos. It seems the cost of DMM's Dyn3 drive and DST servo will be hard to beat (~$630/axis). However, with my plan to use a separate motion control card, the computing power of the drive seems like wasted money. So, the quest to get smart on dumb drives that would take commands to control torque began. That led me to A-M-C (their DPRAHIE‐015S400) and Copley (Xenus XTL-230-36). Those dumb drives look to cost 2-3 times more than DMM's Dyn3!!


What am I missing? Are there other, much cheaper non-DSP drives out there, or is DMM's stuff that good of a deal?

Thanks,
-Steve