Well, what are you powering: the spindle or the power supply? Cant’ be both.
US “220V” single phase is two wires (without the neutral.) EU “220V” single phase is two wires (involving the neutral.)
I’m assuming EU has a safety ground, as the US does, that doesn’t involve the neutral.
Perhaps use an isolation transformer (not step-up or step-down) if you’re really concerned (for some reason unknown to me.)
If you’re powering a power supply, then there’s already an isolation transformer in there for the control electronics.