Abstract: A synchronous generator usable in both a starting mode of operation and a generating mode of operation includes a permanent magnet generator having a permanent magnet and an armature winding rotatable with respect to the permanent magnet, an exciter portion having an exciter armature winding and an exciter field winding rotatable with respect to the exciter armature winding, and a main generator portion having a main generator armature winding and a main generator field winding rotatable with respect to the main generator armature winding. An inverter is coupled to supply power to the main generator portion armature winding via a DC link during the starting mode of operation, and a controller is coupled to the DC link for controlling the magnitude of the DC link current provided to the inverter during the starting mode of operation.

Abstract: A poly-phase no-break power transfer phase balance synchronization sense circuit for an electric power generation and distribution system having a present source of electric power supplying poly-phase AC electric power through a first contactor to utilization equipment and a target source of electric power connectable to supply poly-phase AC electric power to the utilization equipment through a second contactor, a transfer of the source of AC electric power from the present source to the target source being accomplished by closing the second contactor prior to opening the first contactor upon synchronization of the two sources, comprises a circuit for rectifying the poly-phase AC electric power generated by the present source, the circuit generating a first rectified output signal, a circuit for rectifying the poly-phase AC electric power generated by the target source, the circuit generating a second rectified output signal, and a circuit for differentially summing the first rectified output signal and the s

Abstract: An apparatus for generating a sensing signal from a generally periodic multi-phase AC signal is set forth. The apparatus utilizes a plurality of integrator circuits, a single integrator circuit being respectively associated with each phase of the AC signal. The integrator circuits each generate an integrated signal from the respective phase of the AC signal by integrating the respective phase during a time period between sloping transitions of the respective phase. A reset circuit is respectively associated with each integrator circuit for resetting each integrator circuit at the sloping transitions of the respective phase. The integrated outputs are summed by a summing circuit to form the sensing signal.

Abstract: A voltage regulator for a DC power generation system which is comprised of a prime mover driven generator producing an AC voltage output which is rectified to a DC voltage output for use by the system senses the AC voltage output and the DC voltage output, and selects the lower of these two for comparison with a voltage reference to produce a voltage error output signal for use in controlling the DC voltage output. The voltage regulator further comprises tuned compensation of the error output signal prior to use in controlling the DC voltage output. The tuned compensation comprises a proportional-integral lead-lag network. The voltage regulator additionally senses the AC current generated by the generator, and adjusts at least one zero location of the compensation network in response thereto to improve stability margins during light loading conditions, and to improve transient performance requirements under heavier loading conditions.

Abstract: A protection circuit for a bridge rectifier having a plurality of ac inputs coupled to a plurality of line voltages, and a dc output, comprises monitoring circuits coupled to the line voltages for monitoring the line voltages and generating sequential line-to-line voltage signals, conduction circuits coupled to the monitoring circuits for conducting that portion of each of the sequential line-to-line voltage signals having a given polarity, the conducting circuits generating sequential half wave voltage signals having a given polarity magnitude, and discriminating circuits coupled to the conducting circuits for discriminating a faulted rectifier by monitoring the given polarity magnitude of each of the sequential half wave voltage signals. The discriminating circuits generate a protection signal in response to one of the magnitudes of the sequential half wave voltages signals being less than a threshold.

Abstract: A method of increasing service life of an oil comprises placing a quantity of oil within a circuit, and placing a filter in the circuit, the filter having surfaces including interstices which contain a quantity of a liquid additive at a time of placement in the circuit, the additive being washed from the interstices of the filter into solution with the oil during filling and operation of the circuit to form a mixture of the oil and additive which reduces the formation of metallo-organic soaps. The oil may be an synthetic ester based oil or a mineral oil. The additive either reacts with an organic acid formed from hydrolysis of the oil during operation of the circuit to neutralize the acid, or alternatively the additive coats metallic wear particles formed during operation of the circuit so that organic acids formed from hydrolysis of the oil during operation of the circuit cannot attach thereto.

Abstract: A back-up electric power generating system comprises a first variable speed synchronous generator drivably coupled to a first prime mover, a second variable speed synchronous generator drivably coupled to a second prime mover, a converter having a first and a second input coupled to the first and second generators respectively, and an output, and a logic circuit in controlling communication with the converter for designating one of the first or second generators as a primary power source and one as a standby power source, exclusively. The system further comprises a primary voltage regulator selectably coupled to the primary power source generating a controlled current signal to maintain its output voltage at a given level, and a pulse exciter selectably coupled to the standby power source for verifying the operational readiness of the standby power source. This pulse exciter generates a current pulse signal to the exciter field of said standby power source and monitors the output voltage generated thereby.

Abstract: The present invention provides for detecting rotor speed through the use of sense coils on the stator teeth. Voltage ripples caused by the rotor slots is detected by combining the signals of several such sense coils so that the fundamental voltage signal is cancelled or rejected and only the ripple voltages remain, a signal proportional to rotor speed. Several alternative methods for implementing that technique are discussed herein. At low induction motor speeds, the present invention filters out the voltage ripples and incident third harmonics and instead estimates rotor speed from the fundamental voltage. When the induction motor is already being driven by a prime mover, the present invention selects a proper initial frequency command for initial motor start by identifying rotor speed from the PWM inverter. Further, the present invention provides for using a generator to control voltage to the induction motor, with a PWM inverter to control frequency signals to the induction motor.

Abstract: A switched reluctance starter/generator is presented which has a stator mounted within a housing having an outer periphery and a plurality of salient poles defining an inner periphery, the salient poles further defining slots therebetween. A stator cooling sleeve is press fit on the outer periphery of the stator and defines a plurality of cooling channels between the outer periphery of the stator cooling sleeve and the housing. A plurality of phase windings are wound on the plurality of salient stator poles, and phase winding retainers are positioned within the slots for securing the phase windings on the salient stator poles. The winding retainers comprise a triangular base separator, a quasi-dove-tailed retaining member, and two opposing wedge shaped expanders. A rotor assembly is rotatably positioned within the stator, and comprises a hollow shaft assembly and a rotor core having a plurality of salient poles press fit on the outer periphery of the shaft.

Abstract: A system of protection for an AC/DC hybrid electric power generation and distribution system having an AC portion comprising at least one source of AC power producing AC current coupled by first power feeders to a DC portion comprising at least one AC to DC converter producing DC current, the DC current being coupled by second power feeders to utilization equipment, comprises AC current sensors producing current sense signals proportional in magnitude to the AC current and DC current sensors producing current sense signals proportional in magnitude to the DC current. The AC current sensors define an entrance to a zone of protection, and the DC current sensors define an exit from the zone of protection. The AC and DC current sense signals are relationally compared to detect the presence of a differential current fault within the zone of protection.

Abstract: A system of protection which utilizes a simple circuit for the detection and isolation of single and multiple phase to phase and phase to neutral faults between a multi-phase source of electrical energy and a power conversion device driven therefrom. The circuit comprises a current transformer positioned at the neutral aspect of each phase winding of the multi-phase source of electrical energy. These current transformers sense the current generated by the source of electrical energy and produce a signal of proportional magnitude thereby. These proportional sense signals from each of the individual current transformers are transmitted to a controller which vectorially adds these signals to produce a single summed output signal. The controller monitors the percent ripple content of the summed output signal and generates an output protection signal if the percent ripple content of the monitored summed output signal exceeds a predetermined threshold value for a predetermined time interval.

Abstract: An electric power starter/generator, for converting electrical energy from a remote dc electrical power source to mechanical energy to start a turbine engine in the start mode, and for converting mechanical energy from the turbine engine to electrical energy to power utilization equipment in the generate mode, comprises a shaft for transferring rotational mechanical energy between the electric power starter/generator and the turbine engine, a permanent magnet synchronous machine having a rotor driveably coupled to the shaft and a stator. The permanent magnet synchronous machine produces polyphase ac electric power when driven as a generator, and rotational mechanical energy when driven as a motor.

Abstract: A shorted rectififing diode protection system for a synchronous generator having a stationary exciter field which induces a voltage in a rotating exciter armature when energized by an exciter drive current, the voltage being rectified by a plurality of rotating rectifiers and applied to a rotating field winding to induce an output voltage in a plurality of main stator output phase windings, the output voltage being controlled by a voltage regulator having peak excitation current protection means, comprises a circuit for detecting actuation of the excitation current protection and generating a field protection monitor signal, a circuit for discriminating a shorted exciter field and generating a protection lock-out signal, and a logic circuit responsive to the field protection monitor signal and the protection lock-out signal for generating a shorted rectifying diode protection signal.

Abstract: An electronic voltage regulator for generators controlled by means of an exciter field current, comprises an average voltage sensing circuit connected to the output of the generator, a peak voltage sensing circuit connected to the output of the generator, an error signal circuit operatively connected to the average voltage sensing and the peak voltage sensing circuits effective to generate an error signal when the generator's average output voltage varies from a predetermined value or when the peak voltage exceeds a predetermined limit, an exciter field current control circuit operatively connected to the error signal circuit effective to control the generator field current in response to the error signal, and a shock load stabilization circuit operatively connected to the average voltage sensing circuit and to the peak voltage sensing circuit effective to disable the peak voltage sensing circuit upon sensing an application of a shock load to the generator.

Abstract: A system of protection for an electric power generating system having a poly-phase generator switchably coupled through a generator control breaker to a load distribution bus, wherein the generator output voltage is controlled by a generator control unit which utilizes isolated voltage and current sense signals having a magnitude proportional to the output voltage and current for each phase of the poly-phase generator, the isolated voltage and current sense signals being generated by isolated voltage and current sensors, comprises a first circuit for monitoring the magnitude of each of the isolated voltage sense signals and generating a first output control signal if the magnitude of any isolated voltage sense signal is below a first predetermined threshold.

Abstract: A summing transformer includes first and second sets of primary windings and first and second sets of secondary windings. The primary windings of the first set are connected in a wye configuration whereas the windings of the second set are connected in a delta configuration and the sets of primary windings are connected to form a wye-delta configuration having terminals coupled to the outputs of an inverter bridge. Each winding of the first set of secondary windings is interconnected with a winding of the second set of secondary windings. Circuitry is provided for operating the inverter bridge such that a stepped phase output waveform is produced at each of a plurality of phase outputs.

Abstract: A display system and method of displaying data relating to a generator control unit for an aircraft having a first memory of a first type and a second memory of a second type. The first memory contains display data relating to a generator control unit for an aircraft and a plurality of file markers interspersed among the display data, with each of the file markers occupying a respective position in the first memory. The first memory is searched to locate the positions of the file markers. Those positions are stored in the second memory, which is preferably a random-access semiconductor memory. The display data in the first memory is displayed by retrieving a portion of the display data from the first memory based upon the positions stored in the second memory.

Abstract: An electric power generating system comprises a switched reluctance machine, an inverter having a dc input/output coupled to a dc bus, switches responsive to switching control signals for coupling each of the machine's phase windings to the dc bus, and diodes for cross-coupling each of the phase windings to the dc bus. A controller having a number of control inputs and outputs coupled to the inverter monitors the current flowing in the phase windings and the voltage level on the dc bus, and calculates a maximum and a minimum phase current control signal. The controller modulates the switching control signals to regulate the phase current within a range defined by these control signals to maintain the voltage level at a desired level. Upon calculating a positive phase current control signal, the controller generates switching control signals to enable switches at a fixed angle prior to alignment, and generates switching control signals to disable the switches at a fixed angle after alignment.

Abstract: An electric power starter/generator system for a turbine engine capable of transforming mechanical power from the turbine engine to electric power during a generate mode of operation and of transforming electric power from a low voltage dc source to mechanical power to drive the turbine engine during a start mode of operation, comprises a synchronous starter/generator having a poly-phase wound stator, and a rotor rotatably positioned therein, the rotor also being drivably coupled to the turbine engine. Further, the system establishes an electric field in the rotor and directly couples the dc source to an inverter for alternately energizing each of the poly-phase stator windings to drive the starter/generator as a motor. This inverter establishes a rotating electric field in the stator whereby a constant torque is produced by the rotor to drive the turbine engine. Preferably, the inverter is a half wave inverter producing a pseudo-square wave current waveform.

Abstract: A switched reluctance starter/generator is presented which has a stator mounted within a housing having an outer periphery and a plurality of salient poles defining an inner periphery, the salient poles further defining slots therebetween. A stator cooling sleeve is press fit on the outer periphery of the stator and defines a plurality of cooling channels between the outer periphery of the stator cooling sleeve and the housing. A plurality of phase windings are wound on the plurality of salient stator poles, and phase winding retainers are positioned within the slots for securing the phase windings on the salient stator poles. The winding retainers comprise a triangular base separator, a quasi-dove-tailed retaining member, and two opposing wedge shaped expanders. A rotor assembly is rotatably positioned within the stator, and comprises a hollow shaft assembly and a rotor core having a plurality of salient poles press fit on the outer periphery of the shaft.