OK, got some time to work on mine again today. I measured 8V at the lowest setting, and 12.8V at the highest setting. I am running at low speed while troubleshooting magnet configurations.
I have two neodymium disc magnets. They are super-glued to a fender washer that is temporarily taped on the center hub of the fan. The discs are oriented with one N-pole up and one S-pole up. I have a 2" stir bar with center-ring, and the outside edges of the two discs are 2" apart.
I have the stir bar in a Pyrex measuring cup full of water. When I turn on the fan and place the cup right over the magnets, the stir bar rattles around the bottom and turns slowly - probably 5-10 RPM. This is while the fan is going 100's of RPM. It's like the magnets "grab" the stir bar, then drop it, grab and release, etc.
Any help?