Abstract: An electrical machine formed as claw pole generator has a ring-shaped stator provided with windings, a claw pole rotor rotatably arranged inside an opening of the stator, the claw pole rotor having a rotor shaft and an exciter coil arranged coaxially to the rotor shaft, the claw pole rotor also having a peripheral surface provided with a plurality of claw poles which overlap the exciter coil and engage in a finger-like manner with groove-shaped intermediate spaces, at least one axially acting fan units arranged at an end side of the claw pole rotor in a region of an outer periphery, and a plurality of honeycombed structures located in the intermediate spaces and extending in a longitudinal direction of the intermediate spaces so that a cooling medium flows through the structures.