What servo motor setup to get?

[GerryR]

I seem to favor AC servo systems.  They are 3-phase motor systems (with 1-phase power input) using a variable frequency drive (VFD).  I have built a couple of different systems.  They are more expensive than the Enduro DC drive systems, and you need an "Inverter" rated motor to run at low speeds (to handle the extra heat).  I mention this because using a proximity sensor and a metal flag on the hand-wheel, for example, they can be made to stop in any position, depending upon the location of the metal flag, regardless of the speed reducer used.  They, generally speaking, are very reliable systems, as well.  A general DC servo system can be made to do the same, however the systems made specifically for sewing machines do not seam to have this option.  I'm just tossing out another option when considering motor drives for sewing machines.