Its levitated by using neodymium magnets set to repel each other, 1 on each end of the shaft, 2 on each end of the stand so the repelling force suspends the rotor. Magnetic balance is critical here, the rotor needs to be offset to one side a little, hence the stop on one end for it to push against.
The solar cells produce a current from the light, this passes around the coils. At the bottom on the base is another larger magnet.
Now, as we all know, pass an electric current through a magnetic field and you get a force, in this case rotational force, so the rotor turns. As it turns, the next coil is passing the magnet...etc
This particular one is low voltage 0.5v max and so wont run in low light, the moving pic was taken under a 60w light. I am hoping it will run in sunlight - if we ever get any.
Here is a link I found and worked up mine from.
http://www.bis0uhr.de/index.htm?http...t/english.htmlIan