Um, that is going to be one whacking great converter. something to suggest would (wood? [Linked Image]) be to replace or spec the motors to be single phase. Then you are looking at "just a service upgrade" rather than also adding a converter. Your probably into rotary converters to get any kind of efficency out of it, great amount of floor space, and noise too. the noise of the converter probably isn't an issue because a 3 spindle moulder can be heard several counties over anyway.

Just a thought.

Trainwire