**4.2. Effects of the mass of a magnetic top and thickness of the stator magnet**

In this section, the effects of the mass of a levitating top and the thickness of the stator magnet to the height of the restoring centre are discussed.

Figure 16 shows the relationship between the height of the restoring centre *zr* [mm] and the mass of a levitating top *m* [g] when the thickness of the stator magnet is *h* = 60, 40 and 20 mm. Calculated results show that the height of the restoring centre *zr* decreases with an increase in the mass of the top and a decrease in the thickness of the stator magnet.

Calculations were made for various values of the mass of the top in the analytical model described in Table 1. However, there is no restoring centre or levitation area for a heavier or a lighter top than those shown in Figure 16. According to these results, a thin stator magnet may realise successful levitation for wider mass variations.

**Figure 16.** Height of the restoring centre vs. mass of levitating top.
