Patent ID: 7143503

Claim:
A method of manufacturing an electrical machine selected from one of at least two electrical machines, the electrical machine having a desired output rating (P x ) and including a rotor and a stator, the rotor being rotatable about an axis, the stator including a stator core and windings, the stator core having a fixed cross-sectional profile with respect to the axis, the method comprising: determining a total length (L x ) in the axial direction for the rotor based on the desired output rating (P x ), wherein (L x ) satisfies the relationship (0.75(P x /P m )≦(L x /L m )≦1.5 x /P m )), where (P m ) is a chosen maximum output rating for an electrical machine of the at least two electrical machines, and wherein (L m ) is the length corresponding to the length of the rotor for the maximum output rating (P m ); determining a length of the stator in the axial direction to interact with the rotor; producing the rotor including manufacturing the rotor to include a first one or more axial sections when the desired output rating (P x ) corresponds to a first output rating, and manufacturing the rotor to include a second plurality of axial sections when the desired output rating (P x ) corresponds to a second output rating greater than the first output rating, the second plurality of axial sections comprising the first one or more axial sections, the manufacturing the rotor to include the second plurality of axial sections includes manufacturing each of the axial sections with a magnetization pattern of alternating magnetic poles, the magnetization pattern of each axial section of the second plurality of axial sections being different than the magnetization pattern of any adjacent axial section; producing the stator; and assembling the machine.