Abstract: An engine start system for an aircraft includes a first variable frequency start generator (VFSG) including a first exciter and a first stator, a second VFSG including a second exciter and a second stator, a first motor controller and a second motor controller, and a switching system. The switching system is configured to operatively connect the first motor controller to the first stator or the second exciter and operatively connect the second motor controller to the first exciter or the second stator. In a first mode of operation, the first motor controller is operatively connected to the second exciter, the second motor controller is operatively connected to the second stator, the first VFSG generates power, the first motor controller provides a first controlled voltage and frequency to the second exciter, and the second motor controller provides a second controlled voltage and frequency to the second stator.

Abstract: A generator system can include a generator control unit (GCU) configured to control a generator output of a generator. The GCU can be configured to monitor the generator output for overvoltage and attenuate an overvoltage by directing at least a portion of the generator output to a heater element. The GCU can be configured to cause voltage division of the generator output between the GCU and the heater element if an overvoltage is detected to protect one or more GCU electrical components.

Abstract: A method includes pumping coolant into a cooling system of a generator while the generator is generating electrical power. The method includes regulating flow into the cooling system using a pressure relief valve to recirculate a portion of the coolant back to an inlet of the pump. Using the pressure relief valve includes actuating the pressure relief valve based on input from the cooling system and/or from the generator.

Abstract: An electric engine start architecture is provided and includes a motor controller including an exciter inverter and a controller, which outputs a control signal to the exciter inverter, and a generator. The generator includes an exciter receptive of alternating current (AC) from the exciter inverter with the exciter inverter responsive to the control signal, a rotating rectifier receptive of AC from the exciter and configured to convert the AC from the exciter into direct current (DC) and a main machine exclusively drivable by AC fields in the exciter to execute an engine start operation.

Abstract: A rectifier diode assembly is provided and includes first and second bus bars, a diode interposed between the first and second bus bars to define first and second spaces for fluid flow between the diode and the first and second bus bars, respectively, and first and second louvers. The first louvers are compressively interposed between the first bus bar and the diode to extend across the first space for thermally and electrically connecting the first bus bar and the diode. The second louvers are compressively interposed between the second bus bar and the diode to extend across the second space for thermally and electrically connecting the second bus bar and the diode.

Abstract: The present disclosure provides for terminal block cover assemblies for electric generators, and related methods of fabrication and use. More particularly, the present disclosure provides for terminal block cover assemblies for generators for aircraft or the like, with the terminal block cover assemblies having electrical arcing mitigation features and structures, and related methods of fabrication and use. The terminal block cover assemblies of the present disclosure can be utilized to reduce electrical arcing events in environments where de-icing fluid is used in the engine cowl.

Abstract: A permanent magnet generator (PMG) system can include a stator configured to output a voltage, and a rotor assembly configured to be magnetically coupled to the stator and to rotate relative to the stator to induce the voltage. The rotor assembly can be configured to passively attenuate the voltage output from the stator in response to acceleration of the rotor assembly at or above an impulse acceleration threshold.

Abstract: An aircraft oil management system includes a generator, pump, and pump control system. The generator is mechanically coupled to a prime mover via a the rotor shaft and is configured to output three-phase power. The pump is mechanically decoupled from the rotor shaft and delivers oil to the generator. The pump control system drives the pump independent of a rotational speed of the rotor shaft.

Abstract: An assembly of a main stage and exciter stage of an electric machine includes a main stage including a main stage winding, an exciter stage including an exciter winding, and a bus bar assembly to electrically connect the main stage winding to the exciter stage winding. The bus bar assembly includes a terminal post installed to the main stage and extending at least partially through the exciter stage. The main stage winding electrically is connected to the terminal post. A power band contact is installed to the terminal post and is electrically connected thereto. The exciter winding is electrically connected to the power band contact.

Abstract: An aircraft electric power generation and start system (EPGSS) includes a main machine, a starter permanent magnet generator (PMG), a generator PMG, and a carrier injection sensorless (CIS) system. The main machine selectively operates in a start mode or a generator mode. The starter PMG includes a first PMG stator and a first PMG rotor and is configured to rotate along with the shaft. The generator PMG includes a second PMG stator and a second PMG rotor configured to rotate along with the shaft. The CIS system determines one or both of a PMG voltage and a PMG current corresponding to the first PMG during the start mode, and determines a rotational position of the main rotor based on one or both of the PMG voltage and the PMG current.

Abstract: A system includes a generator control unit (GCU). The GCU includes a saturable reactor and a rectifier. Each of the saturable reactor and the rectifier has a separate input to receive AC power from a separate respective permanent magnet generator (PMG). A method includes supplying AC power from a first permanent magnet generator (PMG) of a generator to a saturable reactor of a generator control unit (GCU) that is operatively connected to control the generator. The method includes supplying AC power from a second PMG to a rectifier of the GCU, wherein the first PMG supplies a lower AC voltage to the saturable reactor than the second PMG supplies to the rectifier.

Abstract: A permanent magnet generator (PMG) system can include a stator configured to output a voltage, and a rotor assembly configured to be magnetically coupled to the stator and to rotate relative to the stator to induce the voltage. The rotor assembly can be configured to passively attenuate the voltage output from the stator in response to acceleration of the rotor assembly at or above an impulse acceleration threshold.

Abstract: An aircraft electric power generation and start system (EPGSS) includes a main machine, a starter permanent magnet generator (PMG), a generator PMG, and a carrier injection sensorless (CIS) system. The main machine selectively operates in a start mode or a generator mode. The starter PMG includes a first PMG stator and a first PMG rotor and is configured to rotate along with the shaft. The generator PMG includes a second PMG stator and a second PMG rotor configured to rotate along with the shaft. The CIS system determines one or both of a PMG voltage and a PMG current corresponding to the first PMG during the start mode, and determines a rotational position of the main rotor based on one or both of the PMG voltage and the PMG current.

Abstract: A system includes a generator control unit (GCU). The GCU includes a saturable reactor and a rectifier. Each of the saturable reactor and the rectifier has a separate input to receive AC power from a separate respective permanent magnet generator (PMG). A method includes supplying AC power from a first permanent magnet generator (PMG) of a generator to a saturable reactor of a generator control unit (GCU) that is operatively connected to control the generator. The method includes supplying AC power from a second PMG to a rectifier of the GCU, wherein the first PMG supplies a lower AC voltage to the saturable reactor than the second PMG supplies to the rectifier.

Abstract: An aircraft oil management system includes a generator, pump, and pump control system. The generator is mechanically coupled to a prime mover via a the rotor shaft and is configured to output three-phase power. The pump is mechanically decoupled from the rotor shaft and delivers oil to the generator. The pump control system drives the pump independent of a rotational speed of the rotor shaft.

Abstract: A method includes pumping coolant into a cooling system of a generator while the generator is generating electrical power. The method includes regulating flow into the cooling system using a pressure relief valve to recirculate a portion of the coolant back to an inlet of the pump. Using the pressure relief valve includes actuating the pressure relief valve based on input from the cooling system and/or from the generator.

Abstract: A system includes a generator control unit (GCU). The GCU includes a first rectifier and a second rectifier. Each of the first rectifier and the second rectifier has a separate input to receive AC power from a separate respective permanent magnet generator (PMG). A method includes supplying AC power from a first PMG of a variable frequency generator (VFG) to a first rectifier of a generator control unit GCU that is operatively connected to control the VFG. The method includes supplying AC power from a second PMG to a second rectifier of the GCU. The first PMG supplies a lower AC voltage to the first rectifier than the second PMG supplies to the second rectifier.