Over the years I have junked several cnc machines due to lack of room , too big ,too heavy , whatever the reason. I have saved parts such as servo motors , spindle motors, etc.
mostly red cap fanuc motors . I have coupled up cheap chinese inverters to some 3 phase motors from tool changers, magazine motors to drive drills and bandsaws . Once they work seem to work for years no issues at all . My drill presses tap without tapping heads for example.

It would be amazing to be able to drive a fanuc servo motor with a power supply, some SCR's and an Arduino for example. I haven't really seen anything simple enough on utube for me to understand.
IF, and it seems they do, need feedback to stay live and a high frequency signal then that's probably why no one used them with out a matching drive (because you cant).
I do have the a bunch of servo drives from the same machines. Perhaps its too tricky since it seems several parameters have to be "known" by the drive to make it move correctly. Writing this I think servo motors are going to be way too much trouble. I'll keep them for to replace on working machines here but so far never had one fail.

Spindle Motor!
How about a 8000 rpm (max) fanuc 200V spindle motor do I need a lot of "smarts" to make that turn ? What IF I just connect 3 phase 200V (after transformer) to it will it run full speed or blow up ?
That would be a starting point to know that ! Don't care about encoder or feedback. These things are made so well it seems a shame to dump them .

Any ideas, advice? Has anyone achieved what I'm talking about here ? I have a little knowledge of PWM, Arduino, I can read simple circuits.
I mean simple .. remember Elon said the best part is no part after all we are turning a motor how hard could it be ?