Iceman1000,
I’m familiar with that article, and it’s basically a fair design. You would not need the buck/boost transformer if you want standard 240 volt output. The start circuit shown using the potential relay is not OK for machine shops. Unfortunately if the L1-L3 output voltage falls too low the converter attempts to start again while it’s already running, which means the entire start capacitor bank is thrown across the line. You DON’T want to do this, as it causes an immediate and horrible phase imbalance in the output (caps are 90 degrees and idler motor is 120 degrees), to say nothing of EXTREME mechanical stress on the idler and load motors. Doing something like this will easily fry a CNC control board.
To remedy the design flaw, you could insert a push button in series with the wire going from the relay to the contactor so that in order to start YOU must hold the button down intentionally.
Also, there’s no provision for power loss protection, input overload protection, or output overload protection.
Check out my recent post in this forum on price comparison of rotary, VFD, and Phase Perfect converters before proceeding further. The ‘gory details’ at the end of my first post gives you the basics of how I design large rotary converters. I could help you with this, either by emails or on this forum. However, building a 30 hp rotary is no small job. The biggest I’ve built is a 20. One member has decided to go the Phase Perfect route, and if you can afford it, I’d recommend that. You possibly could get by with a 20 hp Phase Perfect if the sum of your load motors is no higher than 20 hp.
bnelson
