Hi Hannu.
This is an upgrade to the old genny. It's on my web page under Building Turbines.
The coil former i made is a crank and the center was delibratly set very narrow, I really wanted no hole in the center of the coil at all but this was the best I could do, so I alongated and narrowed them. Which allowed more coil space and by getting rid of the hole almost in the center coil allowed me to fit the 12 coils in an 11 inch inner diamter rotor. I inside hole is less then 1/2 inch wide. I viewed the whole coil as a single pole in this design.