Patent ID: 6903485

Claim:
An alternator comprising: a housing; a stator assembly stationarily mounted within said housing; a rotor assembly rotatably mounted within said housing and having a shaft, a first pole piece, a second pole piece, and an excitation winding; said shaft defining an axis of rotation; said first pole piece mounted onto said shaft, and including a plurality of first pole fingers circumferentially spaced about and extending axially therefrom generally in the direction of said axis of rotation; said second pole piece mounted onto said shaft coaxial with said first pole piece and having a plurality of second pole fingers circumferentially spaced about and extending axially therefrom generally in the direction of said axis of rotation; said excitation winding positioned between said first and second pole pieces; said rotor assembly being positioned relative to said stator assembly such that an air gap is defined between said rotor assembly and said stator assembly, and each of said first and second pole fingers having a root, a tip, and an outer surface, said air gap being defined as the distance between said stator assembly and said outer surfaces of said first and second pole fingers, said outer surfaces of each of said first and second pole fingers being is shaped such that the radial width of said air gap becomes gradually larger progressing from said root and extending to said tip, thereby providing space between said stator assembly and said rotor assembly for said tips of said pole pieces to deflect outward during operation of said alternator.