The class I’m working with for my GK-12 fellowship was studying energy last semester. [Paulo] (partner teacher) and I have put together several labs that teach students about energy and power, but wanted something fun to do with renewable energy. I made some lab models a couple weeks ago that were small solar hot water heaters, but they only just survived a day of use by ~120 students. As my girlfriend and others have pointed out, I put a lot of effort into lab aids only to use them once or have them destroyed. So for this lab, I decided to put together a much sturdier model that was designed to take abuse and could survive long enough to be donated to the STEM Outreach Center at NMSU where other K-12 teachers could check it out to use in their classrooms.
The final result was a windmill model. Paulo had done a wind turbine lab in the past where the students built turbines and used them to lift weights, but he wanted a more direct way of showing how turbines generate power.
The thing that sets this model apart from those available from kit manufacturers is that it uses a permanent magnet alternator stepper motor instead of a DC hobby motor. I liked the idea of using an AC generator that worked at the native speed of the turbines because it felt more “real” – no cheap pulleys or exposed gears or DC motors that only “simulate” how a big wind generator works. The blades are small (~30cm diameter), so there’s no way they could turn a long gear train, but I still wanted a scale model of a “real” turbine. I would totally have gone with a double-fed inductive generator just like the big boys, but I had neither the time nor EE expertise to make such a thing 
It took a few iterations to get a nicely working generator, so check out the build process below and try to avoid my mistakes 
