Hi,
No, I would use it on 3 phase. You can't use a 3 phase transformer on single phase, so far as I know. I'd put it back in, drive it with 3 phase power, and have 3 secondaries, each with a bridge rectifier and a capacitor. No real gain in summing them, but I could. Otherwise, just run each supply to each Gecko. Running a 4th axis would mean sharing power with one of the axis, which would probably be fine, especially if it were the Y axis, because I would probably never ever use both at once. Yes, I do have the schematic for the supply, thanks.

cnc1000