DIY Alternator - Rotor
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The rotor is a pretty simple design. It consists of a 12.5 cm diamter piece of PVC pipe with 12 magnets glued to it. Make sure than the side of the magnet that is facing up alternates polarity. BE INCREDIBLY CAREFUL WHILE HANDLING THESE MAGNETS. It is insane how powerful they are. Always use gloves when handling them, and be very careful around any thing metalic. They can give you some pretty good welts if you're not careful.

Start out by cutting a length of PVC pipe. The exact length is not all that important, as long as it fits in the stator. Mine was 9.5cm long, which was about as long as I could have made it.

Use a protactor to make a mark at every 30 degree angle. There should be 12 marks total. Add a small piece of wood 5.1cm (2") long (the length of the magnets) at each mark. I used .635cm (.25") thick plywood for this. The wood spacers are not vital, but they help align the magnets, and they prevent magnets from flying together when you try to glue them.

Another view of the wood spacers.

The magnets I used were cm 5.08cm (2") long by 2.54 cm (1") wide by .95 cm (.375") deep. Make sure you get Neodymium magnets, which are far stronger than standard ceramic magnets. I got grade N45, which is quite strong.  I purchased them from magnets4sale, which had the best prices I could find anywhere online.

Gluing the magnets onto the PVC can be tricky. I highly reccomend gluing them one at at time. These magnets are so strong that they will repell and attract each other even while several inches away. For glue, use epoxy. And use clamps to hold the magnets in place for at least 24 hours. Don't skimp on epoxy, either. When all of the magnets are in place, it should be in a stable equilibrium, but before that, treat this with the utmost caution. As mentioned earlier, the magnets must alternate polarity. A good way to check for this is to hold the magnet you are about to glue down in the orientation you think is correct over the manget to the left and right. If the magnets are repelled from each other, then the orientation is correct. (Note: The wood spacers in this picture are larger because the picture was from an earlier design)

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