Reduction of the cogging torque and the torque ripple of an electrically excited generator by alternative extension of rotor pole pieces

摘要

The present invention relates to a rotor (100) for an electric machine, in particular an electrically excited generator for a wind turbine. The rotor (100) has a rotor body (101) along a circumferential direction (102) about an axis of rotation (103) of the rotor (100) and a rotor tooth with a first pole piece (111) and a second pole piece (121). The rotor tooth extends in a radial direction (104) with respect to the rotation axis (103) from a surface (105) of the rotor body (101). The first pole piece (111) and the second pole piece (121) are arranged at a free end of the rotor tooth. The first pole piece (111) has a first distance (112) with respect to the second pole piece (121) in a first direction (114) that is parallel to the circumferential direction (102). The second pole piece (121) has a second distance (122) with respect to the first pole piece (111) in a second direction (124) that is antiparallel to the first direction (114).