Dynamoelectric machine rotor having interleaved laminations and method for forming

A rotor comprising rotor laminations of a magnetically permeable material which are arranged in a stack for forming a rotor core, the rotor laminations including:

• first rotor laminations each comprising a disk portion having a generally central shaft-receiving opening therein, ribs extending radially outwardly from the periphery of the disk portion at spaced-apart locations around the circumference of the disk portion and a bridge extending along an arc between adjacent ribs, the bridge and pair of adjacent ribs defining a permanent magnet retaining formation of the rotor lamination for receiving a permanent magnet, the permanent magnet retaining formation being generally aligned with permanent magnet retaining formations of other first rotor laminations in the stack;
• second rotor laminations each having a central shaft-receiving opening therein generally aligned with the shaft-receiving openings of the first rotor laminations in the rotor core, the second rotor laminations having a maximum diametrical dimension which is less than the maximum diametrical dimension of the first rotor laminations;
• the first rotor laminations and second rotor laminations being of a magnetically permeable material and interleaved in the stack for use in inhibiting flux leakage along the length of the permanent magnet, at least some of the first rotor laminations in the stack having second rotor laminations located on opposite sides thereof.