Re: [CAD_CAM_EDM_DRO] DC drives

I'm running into lots of older cnc machines that have
DC spindle drives. Could anyone comment on a low cost
replacement (+\- 10 volt analog) drive to replace the missing
and/or failed drive? (these are serious, 20-50amp drives)
Seems like the most cost effective solution is to chuck the
perfectly good DC motor and replace with an AC flux vector
drive (with less torque)........
Thanks