The afe and imple way to achieve a 3-phase transformation is three separate transformers. Then connect them in either a "wye" or a delta arrangement. For the wire size, first find power and voltage, then determine the current. That will determine the wire diameter. There is much literature available about transformer design and building, but note that part of that is aimed at the minimum cost direction rather than maximum efficiency.

Cost isn't problem, I care only about power efficiency, what's about minimum turn for 12v primary ?, can I use only 12 turns for primary and 220 turns for secondary ?, Is I need to fill up bobbins primary side ?, therotically can I just have two turns for primary and 37 turns for secondary ? Why ?

 

A transformer must have enough impedance to limit the current into the primary when there is no load. So that i part of the deign consideration. While I understand transformers, I am not a master at designing them. THAT is why you need to read about them, and not from yoo-toob or similar cartoon sources. In addition, that motor will produce DC and that doe not work well with AC transformers.

 

A transformer must have enough impedance to limit the current into the primary when there is no load. So that i part of the deign consideration. While I understand transformers, I am not a master at designing them. THAT is why you need to read about them, and not from yoo-toob or similar cartoon sources. In addition, that motor will produce DC and that doe not work well with AC transformers.

Not for that motor, I was made stator with about 2kw capacity, three phase WYE, I was made from instruction I get from book

 

3500 RPM can not be a good choice where the expected rpm will be 20-60. Thus You shall look for 1:100 sprocket up-converter but I shall show You well covered science beyound the sprockets. How many LOWER You have the transformation coefficient, so much-fold it decreases the friction force. But as many fold You speed up the output, the same-fold You shall MULTIPLY the friction with. Thus, for illustration, 100:1 gearbox will have a loss factor about 0.98 whilst up-converting gearbox 1:100 will have output in best case 0.2% of in-coming power. All the rest will heat-up the box. If want the good alternator for wind genarator, must have a permanent magnet system (other how magnetisation takes a huge part of power, for example automotive (car) generator have economy factor 15% to 20% (only!). And You need a giant diameter let the speed be high. Hugh Piggott at Scotland`s Scoraig Wind Electric reccomends to make the 1-2 inch thick epoxy pancake with glued in HDD 7 Tesla Neodimium magnets, for example one meter diameter with 120 magnets. Other similar pancake is filled by 120 coils calcualted for correct turns count and wire diameter, then pour with epoxy. Both pancakes turns one against other and even at 20 rpm may harvest a multiple kW power with efficiency hardly over 85%. Yepp, some kind of bearing You shall need of course for example the run-road at the perimeter of pancakes. My experience for encarving it tells the extremely well suited instrument the hand-overgrinder, picture only for illustration what I am speaking about. Fix this overgrinder at 50 cm long extender and then rotate until the ball-path is ready. May process a getinax, or textolyte, even mild aluminium if using carbide plus plus class work-tips (may we call it drillbits?). www.1a.lv/p/virsfreze-pof1200-ae-bosch/43oh