You are probabally going to find there is alot of time and agravation involved in trying to build your own.
What I would do first, is see if you can find a manufacturer that allows their 460v 7.5hp VFD to operate on 1phase, usually the cut off is around 5hp.
This way you would just need a 240/460 1 ph transformer, and the 460VFD's are cheaper on ebay than the 240v models.
Check with SEW, WEG, Square D, Mitsubishi.
What made you buy a 460 model?
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.