Electrical machine, in particular an alternator for a motor vehicle, with a housing (4) and a rotor (10) that is supported, in the housing (4), in a manner that allows it to rotate around a rotation axis (12), the rotor having at least one rotor winding (14), a plurality of claw poles (17) disposed circumferentially, whereby adjacent claw poles (17) have axial claw overlap LÜ and permanent magnets (28) have axial magnet length LM, whereby at least one permanent magnet (28) is located between every two adjacent claw poles (17) and is magnetized so as to suppress leakage flux between the claw poles (17), wherein the following applies for the ratio of axial magnet length LM to axial claw overlap LÜ: LM/LÜ≧0.81.