With the New-To-Me Proper Mill likely to come to my "shop" in the next week or so, I really need to think about powering it: I saw an interesting rotary convertor http://www.mig-welding.co.uk/forum/threads/rotary-phase-converter-plans.32135/#post-350783 which is switchable between 240 and 415 volts from a 240v source - only downside is some needed complication and, for us Europeans, the lack of available 240/415 dual-voltage motors in the 7-10 HP (5 - 7.5kw) range (they seem to stop at 3kw)... I've seen a few rotary convertors where a second idler can be switched in which would make 8HP/6kw feasible, assuming I can find a box big enough for all the required contactors and capacitors (could be 6 or more, particularly with the way I overdo things!) can anyone see a reason why this would be a Very Bad Idea, other than needing some interlocking of the contactors so both motors would switch voltages together etc.? It could be possible to have a "dual-range" convertor where the second motor could be switched in for heavy loads* but it would save a little energy with a single motor if only a couple of HP were required, is my guess. Although I'm quite good with electronics, rotating fields etc. puzzle me ! Dave H. (the other one) * a current-sensing relay feeding the contactor(s)? Manual would do, but why not over-complicate it if I can?