Abstract: A gas turbine engine assembly includes an electromagnetic machine for extracting power from the turbine engine. The electromagnetic machine includes an outer rotor and an inner rotor rotatably supported adjacent to a stator disposed between the inner and outer rotors. The stator has an inner set of windings disposed on an inner surface adjacent to the inner rotor, and an outer set of windings on an outer surface of the stator adjacent to the outer rotor. The inner stator windings form a set of multiple-phase windings, and the outer stator windings form a set of multiple-phase windings.

Abstract: An electromagnetic machine for extracting power from a turbine engine includes an outer rotor and an inner rotor rotatably supported adjacent to a stator. The stator is disposed between the inner and outer rotors. The stator has an inner set of windings disposed on an inner surface adjacent to the inner rotor, and an outer set of windings on an outer surface of the stator adjacent to the outer rotor. A plurality of permanent magnets are disposed on an inner surface of the outer rotor element and on an outer surface of the inner rotor element. Air gaps are defined between the outer surface of the stator and the outer permanent magnets, and between the inner surface of the stator portion and the inner permanent magnets. The inner stator windings form a set of multiple-phase windings, and the outer stator windings form a set of multiple-phase windings.

Abstract: A system for transferring torque between a pair of independently, concurrently rotating shafts of a turbofan engine includes a magnetic gearbox. The magnetic gearbox has a first ring structure, a second ring structure and an intermediate ring structure. Each ring structure has an annular aperture therethrough and a plurality of permanent magnets embedded therein. The intermediate ring structure is disposed between the first and the second ring structures. Each ring structure is coaxially concentric with, and independently rotatable with respect to the remaining ring structures. The first and second ring structures are each coupled to separate ones of the rotating engine shafts, and the intermediate ring is operable to transfer torque between the pair of shafts. Preferably, the intermediate ring structure is coupled to a rotating machine. The rotating machine has a controller, and is operable for adjusting a ratio of torque transferred between the pair of shafts.

Abstract: An electrical machine stator core and method for reducing electromagnetic losses and the consequent heating of the core. The stator core makes use of laminations made from an iron-aluminum alloy at the core-ends of the core, while laminations between the core-ends are formed of a ferromagnetic alloy different from the iron-aluminum alloy. Use of iron-aluminum alloy laminations at the core-ends makes possible a relatively simple technique for generator uprate, by removing laminations located at the core-ends of the stator core, and then installing replacement laminations formed of the iron-aluminum alloy at the core-end, again with the result that the laminations located at the core-ends are formed of an Fe—Al alloy that is different from the alloy of the laminations between the core ends.

Abstract: A power generator that operates at a reduced keybar voltages and currents, flange currents, and keybar voltage differentials includes a keybar shield that reduces the amount of magnetic flux coupling into a keybar of multiple keybars during operation of the generator. By reducing the amount of coupled flux, the keybar shield reduces a keybar voltage and a keybar current in a keybar, reduces keybar current flowing into a flange, and reduces a voltage differential between voltages induced by the flux in the multiple keybars.

Abstract: A power generator that operates at a reduced keybar voltages and currents, flange currents, and keybar voltage differentials includes a keybar shield that reduces the amount of magnetic flux coupling into a keybar of multiple keybars during operation of the generator. By reducing the amount of coupled flux, the keybar shield reduces a keybar voltage and a keybar current in a keybar, reduces keybar current flowing into a flange, and reduces a voltage differential between voltages induced by the flux in the multiple keybars.

Abstract: An electrical machine stator core and method for reducing electromagnetic losses and the consequent heating of the core. The stator core makes use of laminations made from an iron-aluminum alloy at the core-ends of the core, while laminations between the core-ends are formed of a ferromagnetic alloy different from the iron-aluminum alloy. Use of iron-aluminum alloy laminations at the core-ends makes possible a relatively simple technique for generator uprate, by removing laminations located at the core-ends of the stator core, and then installing replacement laminations formed of the iron-aluminum alloy at the core-end, again with the result that the laminations located at the core-ends are formed of an Fe—Al alloy that is different from the alloy of the laminations between the core ends.

Abstract: A stator for a high voltage generator has cable windings that are radially inserted into the stator slots. The stator is assembled as the cable windings are laid into the stator slots. The stator slots are left wide open to allow the cable windings and separator bars to be inserted in the slot as the stator is assembled. The open slots have sidewalls that are defined by stator teeth, which extend radially out from a rotor jig in the stator. As each coil section is laid in a slot, a separator bar is inserted over the coil so that another coil section can be laid into the stator. The coils are stacked in a slot and sandwiched between separator bars also in the slot. The separator bar is keyed to the sidewalls of the teeth to provide structural support for the cable windings.

Abstract: A stator for a high voltage generator has cable windings that are radially inserted into the stator slots. The stator is assembled as the cable windings are laid into the stator slots. The stator slots are left wide open to allow the cable windings and separator bars to be inserted in the slot as the stator is assembled. The open slots have sidewalls that are defined by stator teeth, which extend radially out from a rotor jig in the stator. As each coil section is laid in a slot, a separator bar is inserted over the coil so that another coil section can be laid into the stator. The coils are stacked in a slot and sandwiched between separator bars also in the slot. The separator bar is keyed to the sidewalls of the teeth to provide structural support for the cable windings.

Abstract: A stator for a high voltage generator has cable windings that are radially inserted into the stator slots. The stator is assembled as the cable windings are laid into the stator slots. The stator slots are left wide open to allow the cable windings and separator bars to be inserted in the slot as the stator is assembled. The open slots have sidewalls that are defined by stator teeth, which extend radially out from a rotor jig in the stator. As each coil section is laid in a slot, a separator bar is inserted over the coil so that another coil section can be laid into the stator. The coils are stacked in a slot and sandwiched between separator bars also in the slot. The separator bar is keyed to the sidewalls of the teeth to provide structural support for the cable windings.

Abstract: A rotating machine (e.g., a turbine, motor or generator) is provided wherein a fixed solenoid or other coil configuration is disposed adjacent to one or both ends of the active portion of the machine rotor for producing an axially directed flux in the active portion so as to provide planar axial control at single or multiple locations for rotor balance, levitation, centering, torque and thrust action. Permanent magnets can be used to produce an axial bias magnetic field. The rotor can include magnetic disks disposed in opposed, facing relation to the coil configuration.

Abstract: A rotating electric machine is provided which includes multiple independent control windings for compensating for rotor imbalances and for levitating/centering the rotor. The multiple independent control windings are placed at different axial locations along the rotor to oppose forces created by imbalances at different axial locations along the rotor. The multiple control windings can also be used to levitate/center the rotor with a relatively small magnetic field per unit area since the rotor and/or the main power winding provides the bias field.

Abstract: A multi-interphase transformer for use in power conditioners such as cycloconverters wherein polyphase input power sources with more than six phases and requiring interphase transformers for paralleling the polyphase outputs is disclosed, Such multi-interphase transformers include three or more C-shaped laminated cores with air gaps formed between the angled planar surfaces of the core legs.

Abstract: In a dynamoelectric generator, a low-resistance electrical contact is provided by a multilam or belleville spring mounted between the outer surface of the rotor body and an overlapping retaining ring. This contact forms a conductive current path for high-frequency eddy currents induced on the surface of the rotor and retaining rings at all operating speeds.

Abstract: A solid rotor for a dynamoelectric machine including field conductors and ventilation passages in axial slots is provided with low resistivity thermally conductive axial winged inserts which seal and overlie the slots to form a low resistivity cylinder about the rotor to minimize power losses and associated heating due to harmonic induced eddy currents, enhance the conductive cooling of the rotor, and increase efficiency.

Abstract: An armature of an AC generator includes a plurality of polyphase windings. Each of the polyphase windings is a wave winding passing about substantially the entire circumference of the armature. In one embodiment, four three-phase windings are wave wound in the armature. External connection to each of the phases and the neutral of each three-phase winding is made through four connector quadrants disposed in four parallel planes. Connection to the remaining nine phases and three neutrals are made through further connector quadrants sharing respective planes with the first-mentioned connector quadrants.

Abstract: A rotor of a dynamoelectric machine includes a coating of a high-conductivity metal covering a substantial portion of the surface thereof. The high-conductivity metal reduces resistive heating produced by eddy currents from high-frequency harmonics of an AC power source. In one embodiment of the invention, surfaces of dovetail wedges retaining energizing conductors in logitudinal slots are coated with a copper coating. The pole regions of the rotor include undercut slots to retain chamfered wedges of magnetic material coated with a high-conductivity metal. Retaining rings at opposed ends of the rotor may also be coated with a high-conductivity metal.

Abstract: Active compensation in the form of a pair of trim coils and passive compensation in the form of a solenoidal-shaped magnetic shunt are disclosed for shaping the magnetic field existing in the liquid metal current collector region of an acyclic generator such as to minimize the field component normal to the stator and rotor collector surfaces and thereby substantially eliminate the generation of circulating currents in the liquid metal medium.

Abstract: Current barriers are incorporated in the liquid metal collector region of an acyclic generator to increase the impedance of the lossy circulating current paths therein, thereby to reduce circulating current magnitude.