Abstract: A poly-phase electromagnetic device having n winding phases (n>2) wherein each phase is made from a single conductor strand wound in a lap form configuration. The windings are configured such that on assembly to a slotted magnetically conducive base a maximum of n?1 end turns overlapping is achieved so that the slot packing density can be optimized. The preferred configurations also enable neat and compact terminations which facilitates efficient packaging of the completed device. The windings are made either from discrete bobbins which are electrically interconnected upon assembly to the base, or alternatively from strings of continuously formed sub-windings. The latter process in particular enables full or partial automation of the winding and/or assembly process.

Abstract: The present invention provides a method and machine for producing a slotted wound core (50). The machine includes a punch arrangement (16) arranged to punch apertures in a length of material (12a), a mandrel (22) for receiving the punched material, a control means and a mandrel indexing means. The positioning of the punch arrangement (16) and the mandrel (22) is fixed and the mandrel (22) is arranged to be rotated by the mandrel indexing means after each operation of the punch arrangement so that a roll of punched material is formed on the mandrel (22). The mandrel (22) is rotated by an amount (&ggr;) determined by the control means. The control means determines the indexed amount so that selected apertures punched in the length of material align with one another when the material (12a) is rolled onto the mandrel (22) so that the aligned apertures form respective slots (52) of a desired configuration in the core (50).