Thanks...your answers and Noah's helped out a lot. Funny you mentioned AC servos -- I was wondering about them, too. I was thinking there might be a way to wire up a 'standard' 120VAC tool motor (like from a 10" table saw) to a DC servo driver, by using relays to DC-switch the motor (and also to re-wire the motor from CW to CCW, depending on the direction signal). For a Y or Z axis drive, that might be silly -- but for a large router with a long X axis, maybe it'll be the answer for the required torque and speed.
Anyone ever try using a 120VAC motor, driven from a DC servo driver via relays?
Of course, I do recognize the requirement for an encoder, and the fact that the rotational inertia on a table saw motor might be too great for this...but I was wondering anyway
Thanks,
Chris