I use them to drive a couple of fanuc 5m and one 10m fanuc dc servos for one and a half year whitout any problem on the drives, using non regulated 63 VDC supply, current setting 90% of the max. Encoders are the amt´s 102 v, not using dump circuit, max rapids 180 ipm. Machine is an old Bridgeport VMC 520. The only change i need to made was install linuxcnc in replacement of mach 3 . Never got to tune mach3 for real reliability when i ran the machine few hours whitout stop. Until now the drives perform rock solid.