Abstract: Apparatus is provided for creating heat by electromagnetic induction between relatively rotating components. In RAT applications, part of the nose cone (34) is formed from electrically conductive material (106) which is in thermally conductive relation to the nose cone exterior. A magnetic field is created by components (60) that are spaced apart from the electrically conductive material and relatively rotatable with respect to that material. The electrically conductive material intersects the magnetic field, at least in part, such that eddy currents are created in the electrically conductive material by relative rotation with respect to the magnetic field. These eddy currents create heat which is conducted to the exterior surface of the RAT nose cone. Preferably, the magnetic field is created by a pair of spaced-apart permanent magnets (60) mounted on a support plate (62) inside the RAT hub (28) and immediately behind the nose cone.

Abstract: Apparatus is provided for creating heat by electromagnetic induction between relatively rotating components. In RAT applications, part of the nose cone (34) is formed from electrically conductive material (106) which is in thermally conductive relation to the nose cone exterior. A magnetic field is created by components (60) that are spaced apart from the electrically conductive material and relatively rotatable with respect to that material. The electrically conductive material intersects the magnetic field, at least in part, such that eddy currents are created in the electrically conductive material by relative rotation with respect to the magnetic field. These eddy currents create heat which is conducted to the exterior surface of the RAT nose cone. Preferably, the magnetic field is created by a pair of spaced-apart permanent magnets (60) mounted on a support plate (62) inside the RAT hub (28) and immediately behind the nose cone.

Abstract: A permanent magnet generator having a plurality of permanent magnet generator units which produce a controlled output potential by mutual magnetic flux linkage between the permanent magnet generator units to produce the controlled output potential in accordance with the invention includes a plurality of permanent magnet rotors (20 and 22) mounted on a drive shaft (26) with at least one of the rotors being rotatable with respect to the drive shaft to vary an angular position of the at least one of the rotors relative to the shaft to produce a mutual variable magnitude magnetic axial field extending parallel to the drive shaft; at least one stator (26, 28, 72) disposed at a position axially offset from the plurality of rotors which is magnetically coupled to the variable magnitude permanent magnet axially field; and a mechanism (46, 48) responsive to a stator fault for angularly positioning the rotors relative to each other so that the permanent magnetic field coupled to the at least one stator is zero.

Abstract: The problem of providing field power to a stationary main generator field winding (22) is addressed such that it can be used as a motor. A dynamoelectric machine (12) is operated as both a generator and a motor. An AC-AC exciter (14) is controlled by an exciter inverter (42) to operate as an exciter generator in a generate mode, and as a rotary transformer in a start mode. The exciter inverter (42) supplies low frequency power to an exciter field winding (28) in a generate mode of operation, and supplies high frequency AC power to the generator field winding (28) in the start mode of operation.

Abstract: An excitation system for a brushless generator having a main generator portion including a field winding disposed on a rotor and an armature winding disposed in a stator includes an exciter portion having a set of polyphase exciter field windings disposed in the stator and an armature winding disposed on the rotor and coupled to the main generator portion field winding. A first power converter is coupled to the main generator armature winding and a second power converter is coupled to the set of polyphase exciter field windings. Contactors are operable in a starting mode of operation to couple a source of electrical power to the first and second power converters and are operable in a generating mode to disconnect the source of electrical power from the first and second power converters.

Abstract: This invention relates to a stator winding cooler for a generator having a stator, a fluid-filled rotor mounted for rotation relative thereto and a fluid supply delivering fluid to within the rotor. The stator winding cooler comprises a fluid sprayer disposed within the rotor for accepting fluid within the rotor and delivering the fluid to windings on the stator to cool the windings, the fluid sprayer having a variable orifice therein to render rates of fluid flow through the fluid sprayer insensitive to variations in rotor speed. The stator winding cooler is so designed to function in conjunction with the generator which operates at variable speed. The rate of fluid flow through the fluid sprayer is desired to be held constant to avoid over-spraying end windings at high generator speeds. In the preferred embodiment of the invention, oil, which is used as the cooling fluid, is also passed through a fixed metering orifice within the fluid sprayer which provides a maximum flow rate therethrough.

Abstract: A variable speed, constant frequency generating system has a neutral forming autotransformer connected between a variable speed generator and an AC to AC converter. The converter includes a three phase, full wave rectifier with positive and negative rails connecting the rectifiers with a DC to AC inverter. Each turn of the transformer windings has at least one surface exposed to air for cooling.

Abstract: A variable speed, constant frequency generating system has a neutral forming autotransformer connected between a variable speed generator and an AC to AC converter. The converter includes a three-phase full wave-rectifier with positive and negative rails connecting the rectifiers with a DC to AC inverter. Each turn of the transformer windings has at least one surface exposed to air for cooling.

Abstract: A high-power, high-voltage DC power supply includes a plurality of AC generators, each of which includes a rotor and one or more sets of armature windings wherein the rotors are linked together. A plurality of rectifiers are connected together in series and the armature windings are connected to the rectifiers such that each rectifier produces a fractional voltage which is combined with the fractional voltage developed by other rectifiers to develop a combined output voltage across all of the rectifiers. The armature windings are placed relative to one another such that a plurality of equally-spaced ripple peaks appear in the combined output voltage for each 360.degree. of each armature winding voltage. This in turn minimizes ripple magnitude leading to a desirable decrease in the overall power supply size and weight.

Abstract: In order to improve the efficiency of electric machines, by reducing losses caused by eddy currents induced by high frequency fluxes, the outer surface of the rotor, including the rotor pole face, has a plurality of circumferential grooves. The grooves are provided in axially spaced relation along the rotor. Preferably, the method of reducing losses includes the step of forming the grooves by laser cutting, which permits the width and spacing of the grooves to be minimized so as to maximize loss reduction by increasing resistance to eddy currents.

Abstract: To provide a cooling arrangement for an electric generator capable of supplying oil to a cylindrical rotor cavity in relatively large quantity in order to maintain a predetermined flow rate therethrough while providing spray oil cooling to a rotating rectifier assembly, a stationary non-rotating oil transfer tube is provided. The oil transfer tube extends from one end of a generator housing within a rotating shaft in generally coaxial relation with the one end of the tube being in communication with an oil inlet through the housing and the other end of the tube mounted within a rotating fitting in the rotating shaft.

Abstract: A rotary electric machine including a housing having a stator. The stator includes an armature winding with end turns extending from opposite ends thereof. A rotor is journalled within the housing and the stator and is separated from the stator by an air gap. At least two nozzles are located within the housing, one adjacent each end of the armature, and directed at an associated set of end turns. A pair of partitions are disposed within the housing, one for each end of the armature. Each partition is located axially outwardly of the associated end turns and nozzle. A first air gap seal includes a resilient gasket sealingly engaging a corresponding one of the partitions and the tips of the adjacent end turns while a second air gap seal includes sheet-like seals interposed between layers of the end turns.