Abstract: A system of protection for an electric power distribution system which has at least two parallel power feeders for each electrical phase coupling a source of electrical energy through a contactor device to a load distribution bus comprises a controller, and a parallel feeder current sensor for each parallel power feeder which sense electrical current conducted therein. The parallel feeder current sensors produce output parallel current sense signals proportional to the magnitude of the parallel feeder current sensed, and are coupled to the controller by conductors which communicate the output parallel current sense signals thereto. The controller comprises circuitry which compares the magnitudes of the output parallel current sense signals for each electrical phase.

Abstract: A detector for detecting rotor position of a brushless generator includes a shaft pulse encoder which develops a cycle pulse once per revolution of a motive power shaft and a circuit coupled to armature phase windings of a permanent magnet generator of the brushless generator for deriving a number of interval pulses per revolution of the motive power shaft. A circuit measures time periods between adjacent interval pulses and the measured time periods are converted into an indication of the angular position of the motive power shaft.

Abstract: An apparatus and method for generating a sensing signal from a generally periodic AC signal. The apparatus includes a first integrating circuit (125) for generating a first integrated signal by integrating the AC signal during a time period between positive transitions of the AC signal. The first integrating circuit (125) is reset by pulses from a pulse generator (100) at negative transitions of the AC signal. The apparatus further includes a second integrating circuit (135) for generating a second integrated signal by integrating the AC signal during the time period between positive transitions of the AC signal. The second integrating circuit (135) is reset by a further pulse generator at positive transitions of the AC signal. The sensing signal is generated by taking the difference in magnitude between the first and second integrated output signals.

Abstract: An apparatus comprises a thermal energy generating device and a thermal energy dissipating device having a reduced thermal resistance of the interface between the two. The reduction is achieved by interposing a xylylene polymer layer between the two contact surfaces and applying a surface pressure sufficient to deform the xylylene polymer layer into the surface irregularities of the two surfaces. A reduction in the thermal resistance comparable to that which may be achieved by the use of a silicone grease or an indium foil may be realized if the layer is kept below eight times the air gap mean thickness caused by the surface irregularities. Layer thicknesses beyond this will serve to insulate or increase the thermal resistance between the two surfaces.

Abstract: A method of increasing service life of an oil and a filter in a transmission which converts a variable speed input (10) into a constant speed output (14 or 20) for driving an generator (16 or 22) producing constant frequency power in an airframe in accordance with the invention utilizes a filter having interstices wetted prior to placement in an oil circuit (24) with a quantity of a liquid additive that is washed from the interstices of the filter into solution with the oil during filling and/or operation of the transmission to form a mixture of the oil and additive which reduces the formation of metallo-organic soaps and solids, that are retained in the interstices of the filter.

Abstract: A gate drive circuit for a power switching device having first and second power terminals and a gate terminal comprises an H-bridge rectifier having first, second, third, and fourth rectifiers, the anodes of the first and second rectifiers being mutually coupled at a midpoint to the cathodes of the third and fourth rectifiers. This midpoint is coupled to the gate terminal of the power switching device. A continuous alternating waveform generator is coupled to output selection control logic which selectively applies the waveform to either a first transformer, whose secondary is coupled to the anodes of the third and fourth rectifiers of the H-bridge for transforming the waveform from a control signal reference system to a power signal reference system, or to a second transformer, whose secondary side is coupled to the cathodes of the first and second rectifiers of the H-bridge for transforming the waveform from the control signal reference system to the power signal reference system.

Abstract: A control for an inverter system having first and second inverters that produce inverter outputs wherein the inverter outputs are combined by an interphase transformer (IPT) to produce an AC output includes circuitry for detecting a magnitude of a harmonic component in the AC output waveform and circuitry for developing first and second PWM control waveforms for controlling the first and second inverters, respectively. The second PWM control waveform is phase delayed relative to the first PWM control waveform to in turn regulate the magnitude of the harmonic component and DC content across the IPT is controlled to prevent damage to the IPT.

Abstract: A control for operating an electromagnetic machine in a starting mode of operation wherein the main armature winding of the machine receives electrical power from a controllable power source during the starting mode of operation, comprises a circuit for detecting a magnitude of a parameter of power applied to the main armature winding relative to a stationary frame of reference, a position sensor for detecting rotor position of the electromagnetic machine, a converter responsive to angular position indication for converting the detected parameter magnitude into field and torque producing components relative to a rotating frame of reference, and a circuit responsive to the field and torque producing components for controlling the power source during operation in the starting mode. This control includes an igniter for igniting a prime mover.

Abstract: A method of controllably starting a prime mover, such as a gas turbine engine for an aircraft, in which the prime mover is coupled to a synchronous machine operable in a generating mode in which the synchronous machine converts motive power generated by the prime mover into electrical power and in a starting mode in which the synchronous machine provides motive power to the prime mover to accelerate the prime mover to self-sustaining speed includes three controlled phases: a pre-ignition phase, an ignition phase, and a torque augmentation phase. During each phase the prime mover is accelerated at a predetermined rate. When the motive power provided by the synchronous machine falls below a predetermined level, its operation is converted from its starting mode to its generating mode.

Abstract: A protection system minimizing utilization equipment's exposure to, and power interruption resulting from, an under voltage condition in an electric power generating system includes generator current sensors, generator speed information, an exciter current sensor, voltage sensors, and a controller.

Abstract: A switched reluctance machine comprises a stator having an even plurality of salient stator poles, each of which having a stator winding disposed thereon and electrically coupled one to another to form diametrically opposed pole pairs which may be coupled to an external source of electrical energy, a rotor having an even plurality of salient rotor poles, and at least one compensation coil disposed on each of the rotor poles. The compensation coils are electrically coupled one to another to form diametrically opposed compensation pairs in which flows a flux generating current when one of the stator windings of a pole pair is either open of shorted. The flux generated equalizes the unbalance forces resulting from the faulted stator winding, thereby increasing the fault tolerant capability of the switched reluctance machine.

Abstract: An electrical apparatus, comprises a bridge circuit having a plurality of rectifier legs electrically coupled in parallel. Each of the rectifier legs comprises a first and a second rectifier coupled in series and having an input node therebetween. The electrical apparatus further comprises a switch, having a control input, a power input, and a power output, coupled in parallel with the bridge circuit, and a controller having a control output coupled to the control input of the switch for regulating the opening and closing of the switch. When the bridge/switch element is coupled to the disassociated neutral terminals of a wye wound electrical device, the controller modulates the opening and closing of the switch to provide an current controlled soft start of the device, as well as continued motor drive capability, including acceleration and breaking of the device.

Abstract: A nonvolatile fail-safe system providing protection from bus fault propagation for a multi-channel electric power generating system includes a controller which provides excitation control and protection for a first generator unit, position control for its generator control breaker (GCB) and position control for a bus tie breaker (BTB); protection logic which generates a trip signal for the BTB when a bus fault is detected isolating the load distribution bus from the tie bus, and thereafter generating an excitation isolation control signal and a GCB trip signal isolating the load distribution bus from the generator unit upon sustained presence of the bus fault. A latching generator control relay is electrically coupled in series with the excitation control and is responsive to the excitation isolation control signal for de-energizing the generator by isolating the excitation control.

Abstract: An analog isolation barrier data acquisition system comprises a plurality of satellite sampling modules which are referenced to remote grounds for sensing direct current (dc) voltages which are referenced to these remote grounds. The satellite sampling modules are capable of monitoring several signals which are referenced to its local ground system, and are comprised of three functional blocks: a signal selection block which allows proper selection of the dc voltage signal to be monitored; a modulation block which modulates the selected dc voltage signal to produce a modulated waveform; and a barrier coupling block which transfers waveform information contained in the modulated waveform from the local floating ground reference system to an analog ground reference system.

Abstract: In an aircraft load management center each LRU is addressed by a separate line. Power control units on an LRU are addressed by a bus to which all the LRUs are connected in parallel. Control and status inputs, and status output lines are connected in parallel to the LRUs. A programmable logic unit on each LRU decodes the controller addresses, couples control and status request inputs to the controller. The load management center automatically connects a status signal to the interface output after each control function input.

Abstract: A control unit for an inverter determines an objective function based upon harmonic content in a minimum number of the phase-to-phase AC voltages produced by the inverter and controls the switches of the inverter so as to minimize the objective function to thus control the harmonic content in the inverter output voltages.The objective function may be defined according to the following equation: ##EQU1## where W.sub.k are scaler weighting factors, A.sub.kA, A.sub.kB and A.sub.kC are the Fourier cosine coefficients of the kth harmonic of the inverter phase A, B and C outputs, B.sub.kA, B.sub.kB and B.sub.kC are the Fourier sine coefficients of the kth harmonic of the inverter phase A, B and C outputs, k is the number of the controlled odd harmonic (i.e., k=1, 3, 5 . . . ), and NHARM is the number of the highest controlled odd harmonic.

Abstract: This invention relates to a method of combining a plurality of surface mount technology components and at least one plated through-hole component on a printed wiring board. The method includes applying to a secondary side of the printed wiring board a first layer of a preselected quantity of electrically conductive adhesive and then attaching a first portion of the plurality of the surface mount technology components to the adhesive. The first layer of the adhesive is then reflowed, thereby adhering the first portion of the plurality of surface mount technology components to the secondary side of the printed wiring board. The method then continues by applying to a primary side of the printed wiring board a second layer of the first preselected quantity of electrically conductive adhesive and applying to the primary side of the printed wiring board a second preselected quantity of electrically conductive adhesive.

Abstract: A dynamoelectric machine such as a generator has stator winding end turns which extend beyond the ends of a stator core of the apparatus. The end turns are cooled by conveying fluid coolant from back iron cooling grooves to fluid coolant exit ports through which the coolant is distributed onto the end turns. The cooling arrangement eliminates the need for separate spray rings or nozzles and is low in cost and easy to clean.

Abstract: A two-pole generator rotor assembly (100) including a core (120) and a shaft for mounting the core (120). The shaft includes a pair of shaft end portions (117, 119), with each of the shaft end portions (117, 119) including an integrally formed axially extending retaining wedge portion (134) adapted to mount and retain the core (120) in the rotor assembly (100). The wedge retaining portions (134) include opposed surface portions arranged so as to define therebetween a slot for accommodating the core (120) when the shaft end portions (117, 119) are assembled so that the core (120) and shaft end portions (117, 119) form a rotor subassembly. An outer containment (114) is shrink fitted on the rotor subassembly. A tongue and groove connection (38a, 39) is provided between the respective retaining wedge portions (134) and associated shaft end portions (117, 119) so as to interlock the two end shaft portions (117, 119) together.

Abstract: A two-pole generator rotor assembly including a one-piece shaft, a prewound field coil assembly and a one-piece shaft. The one piece shaft includes a pair of axially spaced shaft end portions and a substantially cylindrical portion integrally formed with the spaced shaft end portions and interposed therebetween. The substantially cylindrical central portion includes a through slot for accommodating the prewound field coil assembly, with the through slot including a pair of opposed wall portions adapted to engage an outer peripheral portion of the prewound field coil assembly and provide means for retention of the prewound field coil.