Patent ID: 7274121

Claim:
A system comprising: an electro-mechanical machine having a rotor that includes a claw-pole segment, the claw-pole segment having a base, at least one claw pole projecting axially from the base in a first direction, and at least one protrusion projecting axially from the base in a second direction opposite the first direction; and a fan assembly that attaches to the claw-pole segment, the fan assembly including at least one opening for receiving the at least one protrusion, a portion of the at least one protrusion extending through and beyond the opening of the fan assembly when the fan assembly is mounted on the claw-pole segment and expanding in response to an application of an axial load, to secure the fan assembly to the claw-pole segment; and the fan assembly including a plurality of fan blades arranged in at least a first set and a second set, the first set including blades of a first configuration and the second set including blades of a second configuration different from the first configuration.