They found that as the floater magnet locked into position, it was oriented close to the axis of rotation and towards the like pole of the rotor magnet. So that, for instance, the north pole of the floater magnet, while it was spinning, stayed pointing towards the north pole of the fixed magnet.
This is different from what was expected based on the laws of magnetostatics, which explain how a static magnetic system functions. As it turns out, however, the magnetostatic interactions between the rotating magnets are exactly what is responsible for creating the equilibrium position of the floater, as co-author PhD-student Frederik L. Durhuus found using simulations of the phenomenon. They observed a significant impact of magnet size on levitation dynamics: smaller magnets required higher rotation speeds for levitation due to their larger inertia and the higher it would float.
“It turns out that the floater magnet wants to align itself with the spinning magnet, but it cannot spin fast enough to do so. And for as long as this coupling is maintained, it will hover or levitate,” says Rasmus Bjørk, and continues:
“You might compare it to a spinning top. It will not stand unless it is spinning but is locked into position by its rotation. It is only when the rotation loses energy that the force of gravity – or in our case, the push and pull of the magnets – becomes large enough to overcome the equilibrium.”
