il be honest, ive never tried to run just single phase on the larger units. if i get time il wire up a 2kw j2s today and try it see if it errors or outputs.
i know i read it on some of mitsubishi literature somewhere though.
most of my machines use up to 750watt mitsi, which are fine on single phase.
my big machines ive left with original dc motors and run via galil. this is one of them
http://www.youtube.com/watch?v=qqQqNpQkD4cwhat are you converting?