Abstract
This paper analyzes the static stability of a diamagnetic levitating rotor. Balancing forces is necessary but does not guarantee stable levitation. Restoring forces (minimizing potential energy) of a levitating magnetic around the zero force point is also required. An equivalent statement is that any small displacement from the zero force point causes the magnet to return to the zero force point. A derivation using this concept gives a stability criterion for cylindrical levitating magnets. The criterion controls the spacing of the diamagnetic plates needed to stably levitate a magnet. This was verified by experiments using regular graphite and pyrolitic graphite plates. When adjustment for plate thickness is included, theoretical stability requirements and experimental results match well.