DIY Alternator - Stator
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The stator is the part of the alternator that doesn't move. In my design, it essentially acts as a cage around the rotor--the part of the alternator that rotates. It is incredibly important that the stator be built as precisely as possible. The stator and rotor generally need to be really close together, but not touching.

I first drew out what I needed to cut exactly to specification. I used a 12.5cm (4.5") diameter piece of PVC pipe for the rotor, so I knew my stator had to be built so that it would have clearance for the pipe and the magnets affixed to the pipe, about 13.5cm (5.315") in diameter. 

These were the exact speficiations I used for the main part of my stator. Please note that TWO of these need to be made. The center bold circle needs to be cut out, as do the outer circles--these circles are where the magnet wire windings will go. The small black spots were holes for 4" long 1/4" bolts that were meant to hold the two halves of the stator together. However, I found that just using pieces of wood worked far better. This will be explained later.

I started by measuring out the discs I needed to cut on 1.27cm (1/2") thick plywood

 Both of the discs marked out.

Cut the discs out using the same methods as the blade hubs (a coping saw or jig saw will work the best) and smooth the edges as needed. As soon as they are cut out, align them as accurately as you can and clamp them together.

It is VITAL that the two discs are identical. In fact, it is more important that they are the same than they match the specifications. So, I screwed the discs together so that there would be no problem with alignment. Whatever you do to one disc, you do the exact same to the other.

Next mark out the inner circle. The wood inside this circle will eventually be cut out.

Mark the inner circle as well

Draw a radial line at every 40 degree angle. This is to align the outer circles.

Mark out the smaller exterior circles. I used a small compass to do this. For some reason in these pictures, I didn't use the lines I drew as guides. It would have been far easier if I had.

It helps a lot if you score the center of each hole before boring the holes out.

I used a wood bore (you can see the bit in the upper left corner) to drill the holes. This worked great, but if you have a large enough power drill bit, that would work too.

You should now have two of the above discs. However, you also need some way to anchor these discs down. The specifications below are what I used for a stand. They worked pretty well, but I sometimes needed to shave some wood off to make it fit correctly, so don't be afraid to do so. Also, at the base of the stand, I added two butresses to keep the stand stable.

The drawn out stand. It is difficult to cut this out without a jigsaw.

The finished stator stand. The holes are for the bolts I was originally planning on using to hold the stator together. Again, I replaced them with wood cross-pieces, so ignore the holes.

This is how the two should look assembled. Again, if you need to shave wood of of the stator stand to make everything fit well, do so. I would not reccomend doing the same to the stator disc itself, however. I connected the disc to the stand using simple wood screws. They held up great.

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