There may be cheaper alternatives avalible for regulation of three phase current.
Run a search at the major Electronics Distributer's for Three Phase or Three Phase Rectifier. Cheapest I found is a 3 phase 100V/ 35 Amp unit at $3.75 US. I think this is much better then 6 single diodes rated the same at $6 something each and there are only Three wires in an two out.
I think cheaper is always better, and these units have the added impact of simplifing our regulation circuit's. Instead of 6 diodes or two Voltage regulator's we can have one simple unit thats inexpensive.
Later,
Kevin L