4. Converting mechanical energy into another form of mechanical energy

These devices work thanks to the forces created directly between two magnets. These forces are proportional to the square of the induction generated by the magnet and the surface area of the magnet $\left(F=B^{2}S\text{/}2{\mu }_0\right)$ . Because of their high induction, rare-earth magnets are particularly interesting for generating relatively high fields. Depending on the orientation of the magnets, two types of phenomena are thus obtained between two parts containing magnets, with numerous applications:

• the phenomena of repulsion or attraction used in :

  • magnetic bearings,...