Multiple magnetic paths machine

Claim 1

An electrical machine having multiple magnetic flux paths comprising: a rotor shaft; a plurality of pole structures mounted axially on said rotor shaft, each producing a magnetic flux on a separate flux path, each of said pole structures comprising a pair of pole pieces and an excitation means sandwiched therebetween for generating opposing magnetic polarities in each of said pole pieces forming said separate magnetic flux path; each of said pair of pole pieces having respective first and second pluralities of axially extending projections, the first plurality of axially extending projections extending toward and being interleaved with the second plurality of axially extending projections; wherein said excitation means in at least one of said pole structures comprises a non-magnetic sleeve mounted on said rotor shaft between the pole pieces of the at least one of said plurality of pole structures and an annular permanent magnet mounted on said sleeve; and wherein said excitation means of at least another one of said plurality of pole structures comprises a permeable core mounted on said rotor shaft between the pole pieces of the at least another one of said plurality of pole structures, and a conductive coil encircling said core for conducting electrical current therethrough.