Quote Originally Posted by Swarfing View Post
It's not quite true you only need one cap? i had to use a few to get the balance right on all the phases. Takes a bit of messing but worked well in the end and saved me using a VFD for the job. Ross it is horses for courses, for me i prefer to use AC and VFD because it is easier. Brushless DC would be second choice but expensive (large servo would be even better). How deep are your pockets?
Cheers, I always thought that ac with vfd was more reliable but restrictive on high rpm also I had heard that torque at low speed can be an issue.

I was more looking at cheap treadmill motors, mainly because I picked one one up on ebay for £1. Not had chance to break it down yet but the specs say 1.75hp continuous and 3hp peak. geared down to 3000 rpm for the mill as it has roller bearings then that would be about 3hp continuous. geared up 1:2 on another spindle it should still achieve 1hp at 12000rpm