Abstract: A wedge for use in an electric machine includes a central portion comprising at least a first material, a first wing integrally attached to the central portion, and a second wing integrally attached to the central portion opposite the first wing, wherein the first wing, and the second wing include a second material.

Abstract: An electrical machine includes a with a parallel first and second phase windings. A first neutral bus is connected to the first phase winding and a second neutral bus is connected to the second phase winding. A first voltage sensor is coupled to the first neutral bus and a second voltage sensor coupled to the second phase winding for monitoring current imbalance between the first and second phase windings.

Abstract: A rotor for an electrical machine includes a rotor core having a plurality of circumferentially spaced apart rotor poles. A plurality of windings are seated in gaps between circumferentially adjacent pairs of the rotor poles. A respective wedge secures the windings in each gap configured to supply Q-axis damping. A pair of end plates are connected electrically to the wedges at opposing longitudinal ends thereof thereby completing a Q-axis winding circuit for each wedge.

Abstract: A rotor for an electrical machine includes a rotor core having a plurality of circumferentially spaced apart rotor poles. Windings are seated in gaps between circumferentially adjacent pairs of the rotor poles. A wedge secures the windings in each gap. The wedge includes a first member made of a first material and at least one second member made of a second material. The second material has a higher electrical conductivity than the first material. The wedge is configured to supply Q-axis damping. A pair of end plates is connected electrically to the at least one second member at opposing longitudinal ends thereof thereby completing a Q-axis winding circuit for each wedge.

Abstract: An auxiliary power unit (APU) generator system for an APU can include a doubly-fed induction generator (DFIG) configured to be operatively connected to an APU to be turned by an APU and to have an output frequency that is a function of an excitation frequency and an APU speed. The system can include a generator control module configured to control the excitation frequency to the DFIG to output a substantially constant frequency with changing APU speed to supply the substantially constant frequency to a load.

Abstract: A generator arrangement includes a housing with a mounting feature, a main generator with an outboard shaft arranged within the housing and axially offset from the mounting feature along a rotation axis, and a permanent magnet generator. The permanent magnet generator has an inboard shaft arranged within the housing between the main generator and the mounting feature. The outboard shaft is coupled to the inboard shaft to provide rotation to the main generator through the permanent magnet generator. Accessory gearboxes and methods of generating electrical power are also described.

Abstract: An electric motor control system including an electric motor having a winding with a first and second end, a motor controller having a phase lead, the motor controller operable to direct a phase current to the phase lead. The electric motor control system also includes a first switching device that provides an electrical connection between the phase lead and the first end of the first winding when in a disabled state, and thereby flowing the phase current from the phase lead to the first end of the first winding, and a second switching device operably connected to the motor controller and providing an electrical connection between the second end of the first winding and a common point, when in an enabled state. The motor controller is operable to change the state of the first switching device to enabled, and the second switching device to disabled, under selected conditions.

Abstract: A generator cooling assembly is provided and includes a rotor, a generator assembly and an air-cycle machine (ACM). The generator assembly includes a generator housing, a generator housed in the generator housing and a shaft coupled to the rotor to transmit shaft power from the rotor to the generator to drive the generator. The ACM is housed in the generator housing and is receptive of air. The air is cooled by the ACM and output from the ACM to the generator as fully cooled air to cool the generator.

Abstract: A generator arrangement includes a housing with a mounting feature, a main generator with an outboard shaft arranged within the housing and axially offset from the mounting feature along a rotation axis, and a permanent magnet generator. The permanent magnet generator has an inboard shaft arranged within the housing between the main generator and the mounting feature. The outboard shaft is coupled to the inboard shaft to provide rotation to the main generator through the permanent magnet generator. Accessory gearboxes and methods of generating electrical power are also described.

Abstract: A multiphase switched flux electric machine including a rotary drive shaft, a ferromagnetic salient pole rotor assembly operably coupled to the rotary drive shaft having a plurality of rotor teeth defining a circumferential outer periphery of the rotor assembly, and a stator assembly. The stator assembly includes a ferromagnetic stator core, a plurality of permanent magnets positioned substantially equidistant about an inner circumference of the stator core, a plurality ferromagnetic stator teeth mounted to the permanent magnets on the stator core with distal ends forming an inner periphery of the stator assembly, the inner periphery proximate the outer axial periphery of the rotor assembly separated by an air gap; and a plurality of stator coils with an axial active portions disposed within selected teeth of the plurality of ferromagnetic stator teeth.

Abstract: An assembly for an electric machine including a core with a plurality of teeth extending radially inward from the core, the plurality of teeth defining a plurality of slots for receiving coils, a plurality of coils, each coil wrapping around a respective tooth, a separator in one of the slots including a first leg joined at an angle to a second leg for separating adjacent coils within the slot, an insert between the first leg and the second leg for at least partially filling a space between the first leg and the second leg, and a potting filling space within the slot between the separator, the plurality of coils, and the insert.

Abstract: A permanent magnet machine includes a rotor including a rotor hub and a plurality of permanent magnets embedded in the rotor in a circumferential pattern. The rotor includes a respective bridge between each circumferentially adjacent pair of the permanent magnets. Each bridge is of a different material than that of the rotor hub, and the rotor hub and bridges are integral with one another.

Abstract: A system can include a first generator configured to operate in a first speed range to produce a predetermined output characteristic, a second generator configured to operate at a second speed range different from the first speed range to produce the predetermined output characteristic, and a controller configured to activate the first generator at and/or above a first low activation speed and at and/or below a first high activation speed within the first speed range. The controller can be configured to activate the second generator at and/or above a second low activation speed within the second speed range. The controller can be configured to deactivate the first generator at and/or above a first high deactivation speed. The controller can be configured to deactivate the second generator at and/or below a second low deactivation speed.

Abstract: A core for an electric machine includes a core body arranged along a rotation axis and a winding. The core body has two or more teeth including a first tooth and a second tooth that are circumferentially spaced from one another about the rotation axis. The winding is to the core body and includes two or more coils connected electrically in series with one another. A first of the coils is seated circumferentially about both the first tooth and the second tooth to define a distributed pole circumferentially spanning both the first tooth and the second tooth. Electric machines and methods of making cores for electric machines are also described.

Abstract: A generator includes a stator with a stator winding, a rotor core with a rotor tooth supported for rotation relative to the stator about a rotation axis, and a field winding. The field winding includes a field coil that is seated on the rotor tooth. The field coil includes two or more flat wire turns stacked with one another and formed such edges of the field coil tightly engage circumferential faces of the tooth. Electrical systems and methods of making generators are also described.

Abstract: An electrical machine includes a stator defining a plurality of circumferentially spaced slots. A layered conductor is wound into the slots. The layered conductor includes a plurality of layers wherein at least two adjacent layers in the plurality of layers have electrical conductivities that are different from one another. The at least two adjacent layers can form an interface therebetween that is tangentially aligned with a circumferential direction around the stator. The at least two adjacent layers can be in electrical communication with one another with no intervening insulator therebetween. One of the at least two adjacent layers can include a relatively high electrical conductivity metal, and another one of the at least two adjacent layers can include a relatively low electrical conductivity metal.

Abstract: An assembly for an electric machine including a core with a plurality of teeth extending radially inward from the core, the plurality of teeth defining a plurality of slots for receiving coils, a plurality of coils, each coil wrapping around a respective tooth, a separator in one of the slots including a first leg joined at an angle to a second leg for separating adjacent coils within the slot, an insert between the first leg and the second leg for at least partially filling a space between the first leg and the second leg, and a potting filling space within the slot between the separator, the plurality of coils, and the insert.

Abstract: An electric motor control system, including an electric motor having a first winding set including first and second parallel windings, the first and second windings operable to each current based on the combined phase current, and a differential current sensor operably coupled to the first winding and the second winding. The differential current sensor measuring a differential current flowing through the first winding and the second winding and operable to transmit a signal indicative of the differential current based on the measuring. The system also includes a motor controller connected to the electric motor, the motor controller operable to direct the combined phase current through the phase lead, receive the differential current signal, determine if the differential current flowing through the winding set exceeds a selected threshold, and identify a health status of the motor winding set as degraded if the differential current exceeds the selected threshold.

Abstract: A rotor for an electrical machine includes a rotor core having a plurality of circumferentially spaced apart rotor poles. Windings are seated in gaps between circumferentially adjacent pairs of the rotor poles. A wedge secures the windings in each gap. The wedge includes a first member made of a first material and at least one second member made of a second material. The second material has a higher electrical conductivity than the first material. The wedge is configured to supply Q-axis damping. A pair of end plates is connected electrically to the at least one second member at opposing longitudinal ends thereof thereby completing a Q-axis winding circuit for each wedge.

Abstract: Disclosed is a system for a gas turbine engine, the gas turbine engine comprising a primary shaft, the system including a rotor shaft; a plurality of components connected to the rotor shaft, including a wound field synchronous main machine (MM) and a permanent magnet generator (PMG); and wherein the PMG, alone or with the MM provide torque to change rotational speed of the rotor shaft, thereby changing rotational speed of the primary shaft.