Method of optimizing armature balance through lamination orientation

Claim 1

In an electrical device including an electrical flux conducting rotor having an axis of rotation, said rotor being formed with a stack of sheet metal blanks laminated together with the blanks extending perpendicular to said axis of rotation, said blanks having similar outline shapes disposed in alignment in the stack, the outline shape of each blank having a symmetry such that any blank in the stack is capable of being stacked in outline alignment with any other blank when displaced in such stacked relation angularly about the axis of rotation of said rotor a plurality of equal angular divisions of 360°, the improvement which comprises each blank having a predetermined orientation based upon being similarly blanked from the same metal sheet, the blanks of the stack being arranged in one group or a plurality of groups, each of which contains a plurality of successive blank sections numbering at least four, each blank section containing a number of blanks equal to the number of blanks in each blank section of the associated group, the blanks of the blank sections of each group being displaced angularly with respect to said predetermined orientation relative to one another so as to statically and dynamically balance the orientation of the blanks of the blank sections of each group about the axis of rotation of said rotor, each group having at least two blank sections in one half of the associated group and an equal number of blank sections in the other half of the associated group, the blank section of one half of each group being relatively angularly displaced in a similar manner but in a mirror image relationship to the blank sections of the other half of the associated group.