A stepping motor comprises a stator (3) with at least two magnetic circuits and a rotor (2) that is rotatably mounted on the stator through a single ball bearing having four contact points. The rotor comprises a mutipolar magnet (5) essentially in the form of a disc having a central opening (6). One rotor portion (7) is fixed at one radially external portion of the magnet (5), while one radially internal portion of the magnet is arranged within the air gap of said magnetic circuits.
An induction motor for the conversion of electrical energy into mechanical energy is integrated with a wheel system or brake system of a transportation apparatus, ane especially human powered apparatus.
