Roger wrote: > Gene, > What I was thinking about was using steppers to reliably power big iron on the > Bridgeport scale. Kelinginc.net sells big steppers (nema 34, 1800 oz) for > $180. If you add an encoder and a G203V 80 volt/20 amp drive you are under > $400 per axis. > Well, if you restrict yourself to lower speeds, this will work. As you go up in speeds, the torque drops off, and the margin of safety for not losing steps gets narrower. > That is a pretty attractive price and makes retrofitting old Faunic based > machines with their screwy AMP's with resolver feedback instead of tachs a > whole lot more reasonable. A stepper based conversion would not have the > performance of a servo system but could still be useful in a home shop. > It is almost always easier and cheaper to keep the motors, when you are getting into larger machine. If you can find a surplus motor at a real bargain, that may not be true. For instance, I now have resolver to quadrature converters to read resolvers.
And, if you are thinking of putting steppers on REALLY big machines, the 12 foot tall Mazaks, Cincinnattis, etc., then really forget it. 150 Lb steppers do exist, but they are very rare and will go for thousands of $. The drives will cost even more. Jon ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
