Making the Stator

I deceided to make the stator for the wind turbine next, as it's a bit of a break from the CNC. Although the mold and coil winding form were cut out on it.

First off I needed some coils to cast into the stator. Seeing as there is no iron/steel backing plate to complete the flux path of the magnets, I needed a fairly high number of turns to get enough voltage for charging a 12V battery. I thought I'd use a thin guage of wire to get as many turns as possible into the available space and then, after some testing of output voltage, I could wire, series groups of coils in parallel. I'm aiming to start with 3 groups of 4 coils and go from there. Winding the coils is pretty mundane. I made a former on which to wind the coils, to try and get some uniformity of shape and size. Each coil received 200 turns.

 

The mold was made, again from MDF. The outline profile of the stator was cut out and screwed down to a flat board. I then positioned the 12 coils inside the mold, ready for pouring. As usual, I got carried away with the task at hand and forgot to take more photo's. I used a fibreglass resin and tissue, the type you get for repairing car bodywork etc... This stuff gets really hot and sets in around 20 mins. After pouring the resin into the mold, I screwed another board down over the top of the entire mold to hold it all down nice and flat. Before I realized what I was doing, I'd got the stator on the wind turbine (well as much of it as I've built so far), and still hadn't taken a picture. So here's a piccy of the fibreglass stator on the machine, as it is so far.

 

I also made the bracket that holds the stator in place, so that once the stator was ready, it could be tried out to see how it fits. The holes were drilled on the drill press and were drilled through the fibreglass stator at the same time.