So what do ya'll think? I do not have three phase power here and $40k to get it, well My little shop can't pull that off.
I have been running my Hitachi Seiki VK-45 using a rotary phase converter (yes it is a big one). These things don't make the cleanest three phase. Motors and such don't really care but control systems do. I run the power from the converter into a three phase variac to balance the output. Without it the converter puts out something like 205, 285, 230 volts. With the variac I can dial it in to 220 across the board. Part of the problem I am guessing is that it does not follow load variations well.

I try to be careful and have reduced the braking and acceleration of the spindle to much longer times that is recommended by Hitachi Seiki. My problem is the Fanuc spindle drive A06B-6055-H106 has failed twice now in about a 10 year period and I don't run the machine everyday, hours on end and try to baby it as much as I can. "They" want $2800 to $3500 to fix said spindle drive. Last time they did it, it died two weeks after the six month warranty.

I asked Fanuc how I might better protect this @$#%$@! fragile darned thing, they just said 'get three phase power'....there is that $40k problem again. There must be something out there that can better condition the power that I have.

Any ideas?