Abstract: Some dynamoelectric machines develop shaft E.M.F.'s during operation which lead to circulation currents in the shaft of the machine. The shaft current will attempt to flow through the bearings of the machine, unless some action is taken to prevent or limit said current flow. This invention minimizes the circulation of rotor shaft currents by providing a return path for the shaft current through an insulated conductor located in the center of the shaft of the machine. The insulated conductor is electrically attached to the shaft at the ends of the conductor. The conductor may extend the length of the shaft.

Abstract: In an alternating current pipe-type cable system in which a group of individual insulated conductors are loosely disposed eccentrically within a conduit, an electromagnetic field shaping device interposed between the conductors and the conduit wall, so as to line the wall is configured so as to reduce eddy current losses in the conduit and in the conductors. The device is in the form of a slotted cylinder positioned so that the slot is diametrically opposite the group of conductors thereby to redistribute the magnetic flux induced. The device is preferably laminated in the radial and axial directions.