Electrical machine

An electrical machine, e.g., a power generator such as an alternator for a motor vehicle, is disclosed. The electrical machine includes a rotor and a stator, and the rotor is non-rotatably secured to a shaft having a shaft end that protrudes out of the rotor. A belt pulley is arranged at the shaft end for coupling to a drive. A bearing is non-rotatably secured to the shaft between the belt pulley and the rotor. A spacer ring is non-rotatably secured to the shaft between the belt pulley and the bearing. A gap which encircles the shaft is disposed between the belt pulley and the spacer ring, and between the spacer ring and the bearing, respectively. A plurality of blades directed radially outwards are arranged in at least one of the respective gaps. The blades convey incoming contaminated air to the outside and protect the respective gap against dirt.