Abstract: A rotor assembly for an electric motor comprising rotor elements each having a body portion and pole portions formed integrally as a pressing from strip steel, Each successively formed rotor element is formed with its pole portions offset relative to its body portion by an amount different from the offset on the previously formed rotor element. The rotor elements are produces by the use of a progressive die assembly to punch the rotor elements from strip material. At least part of the pole portion of the rotor element is produced by a first die member, and at least a part of the body portion is produced by a second die member. Relative movement is effected between the first and second die members between successive punching operations to change the pole portion offset.

Abstract: A rotor assembly for an electric motor comprises rotor elements formed integrally as a pressing from strip steel, whereof adjacent rotor elements (8) comprise pole portions (12) which are mutually offset, particularly with respect to a central plane B-B of the body portion (10) of the rotor element. In particular each rotor element is produced by the use of a die assembly to punch the rotor element from strip material, part at least of the pole portion of the rotor element being produced by a first die member, and part at least of the body portion being produced by a second die member, in which relative movement is effected between the first and second die members between successive punching operations.