Abstract: An electric machine includes a rotor, a stator, and an air gap defined by a space between the rotor and a stator. A volume of cooling fluid is located in the air gap and in contact with both the rotor and the stator. A method for cooling the electric machine includes sensing speed of the electric machine and varying the volume of coolant located in the air gap in response to the sensed speed of the electric machine.

Abstract: A permanent magnet rotor for an electrical generator has pole pieces with permanent magnets. A control coil is associated with the pole pieces. A current flow through the coils is controlled to achieve a desired output voltage at an output for the generator.

Abstract: In typical commercial/aerospace applications, synchronous generators provide power to both the high voltage and the low voltage loads. This disclosure describes a method of regulating the output voltage for all of the loads.

Abstract: A fault protection system provides fault protection to a permanent magnet (PM) generator. The fault protection system includes one or more overload and short-circuit protection circuits, an unbalanced protection circuit and a thermal protection circuit. The overload and short-circuit protection circuit detects both overload and short-circuit conditions by monitoring current and voltage generated at a single phase by the PM generator. The unbalanced protection circuit monitors and compares current and voltage generated associated with at least two individual phases to determine unbalanced conditions between the phases. The thermal protection circuit detects a thermal overload condition by monitoring the temperature of the PM generator.

Abstract: A self-regulating permanent magnet device has a first rotor segment and second rotor segment, each supporting a set of permanent magnets, wherein the position of the second rotor segment relative to the first rotor segment is modified based on the speed of the self-regulating permanent magnet device. By modifying the position of the second rotor segment relative to the first rotor segment, the alignment between their respective sets of permanent magnets, and therefore, the electromotive force (emf) generated in the stator coils is regulated. The position of the second rotor segment is defined by the connection of a torsion spring between the first rotor segment and second rotor segment and a reactionary torque device connected to the second rotor segment. The torsion spring creates a spring force that acts to maintain the alignment between the first rotor segment and the second rotor segment.

Abstract: A permanent magnet rotor for an electrical generator has pole pieces with permanent magnets. A control coil is associated with the pole pieces. A current flow through the coils is controlled to achieve a desired output voltage at an output for the generator.

Abstract: In typical commercial/aerospace applications, synchronous generators provide power to both the high voltage and the low voltage loads. This disclosure describes a method of regulating the output voltage for all of the loads.

Abstract: A permanent magnet generator voltage regulation system controls the output voltage of a permanent magnet generator. The output voltage of the permanent magnet generator is controlled by configuring the electrical connection of the stator coils. A monitoring device monitors the output voltage generated by the PMG, and a controller selectively configures the stator coil configuration based on the monitored output voltage. A switch array having a number of switches is connected to the stator coils, the switches being controlled by the controller to configure the electrical connection of the stator coils. For instance, to maximize output voltage generated by the PMG, the controller causes the switch array to connect the stator coils in series with one another. To reduce the output voltage, the controller causes the switch array to connect at least some of the stator coils in parallel with one another. In this way, the output voltage of the permanent magnet generator can be coarsely controlled.

Abstract: A power generating system provides high voltage AC power and low voltage DC power using a single generator. The generator includes a rotor and a stator that is wound with a first winding and a second winding. The first winding has a greater number of turns than the second winding and generates high voltage AC power in response to the rotating magnetic field created by the rotor. The second winding generates low voltage AC power in response to the rotating magnetic field created by the rotor. The low voltage AC power is converted to low voltage DC power by a rectifier. The low voltage DC power is further controlled by a DC-DC converter to generate controlled DC power. A controller monitors the DC power generated by the DC-DC converter, and generates pulse width modulation signals that are provided to the DC-DC converter, selectively increasing or decreasing the controlled DC power provided by the DC-DC converter.

Abstract: The output voltage generated by permanent magnet generator (PMG) is regulated by controlling a buck/boost voltage applied to selected sub-coils within the PMG. The PMG includes a number of stator coils that are each divided into a number of sub-coils. A buck/boost voltage source generates a buck/boost voltage, and a controller connected to monitor the output voltage generated by the PMG selectively applies the buck/boost voltage to selected sub-coils based on the monitored output voltage. In this way, the controller is able to regulate the output voltage by selectively controlling the buck/boost voltage applied to the selected sub-coils.

Abstract: A self-regulating permanent magnet device has a first rotor segment and second rotor segment, each supporting a set of permanent magnets, wherein the position of the second rotor segment relative to the first rotor segment is modified based on the speed of the self-regulating permanent magnet device. By modifying the position of the second rotor segment relative to the first rotor segment, the alignment between their respective sets of permanent magnets, and therefore, the electromotive force (emf) generated in the stator coils is regulated. The position of the second rotor segment is defined by the connection of a torsion spring between the first rotor segment and second rotor segment and a reactionary torque device connected to the second rotor segment. The torsion spring creates a spring force that acts to maintain the alignment between the first rotor segment and the second rotor segment.

Abstract: A fault protection system provides fault protection to a permanent magnet (PM) generator. The fault protection system includes one or more overload and short-circuit protection circuits, an unbalanced protection circuit and a thermal protection circuit. The overload and short-circuit protection circuit detects both overload and short-circuit conditions by monitoring current and voltage generated at a single phase by the PM generator. The unbalanced protection circuit monitors and compares current and voltage generated associated with at least two individual phases to determine unbalanced conditions between the phases. The thermal protection circuit detects a thermal overload condition by monitoring the temperature of the PM generator.

Abstract: A permanent magnet generator voltage regulation system controls the output voltage of a permanent magnet generator. The output voltage of the permanent magnet generator is controlled by configuring the electrical connection of the stator coils. A monitoring device monitors the output voltage generated by the PMG, and a controller selectively configures the stator coil configuration based on the monitored output voltage. A switch array having a number of switches is connected to the stator coils, the switches being controlled by the controller to configure the electrical connection of the stator coils. For instance, to maximize output voltage generated by the PMG, the controller causes the switch array to connect the stator coils in series with one another. To reduce the output voltage, the controller causes the switch array to connect at least some of the stator coils in parallel with one another. In this way, the output voltage of the permanent magnet generator can be coarsely controlled.

Abstract: A power generating system provides high voltage AC power and low voltage DC power using a single generator. The generator includes a rotor and a stator that is wound with a first winding and a second winding. The first winding has a greater number of turns than the second winding and generates high voltage AC power in response to the rotating magnetic field created by the rotor. The second winding generates low voltage AC power in response to the rotating magnetic field created by the rotor. The low voltage AC power is converted to low voltage DC power by a rectifier. The low voltage DC power is further controlled by a DC-DC converter to generate controlled DC power. A controller monitors the DC power generated by the DC-DC converter, and generates pulse width modulation signals that are provided to the DC-DC converter, selectively increasing or decreasing the controlled DC power provided by the DC-DC converter.

Abstract: A method and system for monitoring the performance of a permanent magnet device, such as a motor or generator, and providing early detection of motor performance deterioration. The back electromotive force (EMF) of the motor is measured at selected conditions when the motor is in a normal healthy condition to obtain a reference signature response. A measured signature is then obtained periodically during the life of the motor at the same conditions as the reference signature to check the current back EMF characteristic of the motor. If the measured signature deviates from the reference signature by a predetermined threshold, it indicates that the motor performance has degraded to a condition requiring attention.

Abstract: A Hall-Effect sensor assembly for a rotating electric machine comprises a thin, removable tubular substrate with Hall-Effect sensors and associated connection wiring mounted on it that slips underneath the wound stator end turns of the stator for the rotating electric machine to make the assembly easily removable for installation and repair.

Abstract: A voltage regulation system maintains the output voltage of a permanent magnet generator at an essentially constant level. The stator coils located within the permanent magnet generator are divided into a number of sub-coils. A buck/boost voltage can be applied to selected sub-coils such that the output voltage generated by the permanent magnet generator is increased or decreased. A number of switches are connected to the sub-coils to allow the sub-coils to be connected in a number of different configurations. Connecting the sub-coils in a particular configuration and applying a buck/boost voltage to selected sub-coils based on the monitored output voltage allows the voltage regulation system to maintain an essentially constant output voltage.

Abstract: An electric power generating system comprises a low reactance, large airgap permanent magnet generator driven by a hydraulic motor to generate a poly-phase AC output voltage. Because the permanent magnet generator is a low reluctance, large airgap machine, the output voltage regulation is low over the desired loading range of the system. The output voltage is controlled within acceptable limits by trimming the output speed of the hydraulic motor through the use of a servovalve. The control for the servovalve senses a parameter of output power and generates a speed control signal to compensate for deviations in the generator output. The system includes protection circuitry which monitors at least one parameter of the output power. This protection circuitry generates an output protection signal in response to a deviation in the monitored parameter which exceeds predetermined limits.

Abstract: An improvement in a generator having a rotor, a stator, a magnetic field structure disposed on one of the rotor and the stator and an armature winding disposed on the other end of the rotor and the stator wherein the armature winding is disposed in a useful flux path comprises an additional armature winding disposed in a leakage flux path wherein auxiliary power is developed by the additional armature winding for one or more electrical loads.

Abstract: A method of and system for controlling an induction motor detects input frequency to the motor and connects windings of the motor in one of a plurality of configurations in dependence upon the detected frequency.