Well considering your buget it would be a bit more then your planning on spending. I was looking at it from the converter to vfd to motor app.
A 15hp derated to 10hp would be a bit much on a 3hp motor. There are single phase input 3 phase output vfds availble specificly designed for 3hp for...
If your only going to be using 1 motor at a time, why not just use a vfd, and skip the rotory converter. Take your largest motor that is going to be ran say 10hp X (1.5) at least = 15hp. Single phase it and derate the vfd to 10hp. But make sure you do not drop a motor across the outputs while...