I have a Thompson 12 x 24 ,5 horsepower surface grinder .I used a 10 hp
rotery phase
converter on it for years i could not get a good finish on it. I tried
every thing.I was about to get rid of the machine.And someone on this
group told me that on rotery phase converters
there phases may not be 120 deg. apart or something like that . There
for the motor would not run without vibration.I could not feel any
vibration. So i put a vfd on it ,single phase in 3 phase out and i now
get a mirror finish.For a surface grinder get a vfd.
Tim kallam
Kallam machine