Abstract:
A method and system for improving the reliability of an electronic system (20) formed of subsystems (22) which perform different functions. The electronic system (20) is analyzed to determine which of the subsystems (22) is most likely to cause a system failure and these subsystems (22) are targeted for monitoring and/or correction by a microcontroller unit (28). The microcontroller unit monitors the inputs (IN) and outputs (OUT) of the targeted subsystems (22) and determines when an output (OUT) is inappropriate for the corresponding input (IN). When an error is detected, an error code is stored in memory (36) for future reference. When the microcontroller is in a correcting mode, open collector drivers (42, 44) are used to make corrections for an error in a digital output. Where the error generated is for an analog output, a digital to analog converter circuit (46) and voltage followers (48) are employed to impress the correct analog signal on the inappropriate output. The method and system are particularly applicable to weapons systems due to the possibility of critical failures in these systems and the limited space available for using redundant circuitry to improve reliability. In particular, the method and system are applicable to the gyro control unit (GCU) and the command control unit (CCU) of a torpedo for monitoring and/or correcting for failures in those systems.
Abstract:
Activation of thermoplastic, such as polyphenylene sulfide, polysulfone, and polyether sulfone thermoplastics by subjection thereof to bromine. The activation process is carried out at relatively low temperatures, such as below 200oF and illustratively, may be carried out at room temperatures. The bromine, in the illustrated embodiment, is provided in an aqueous solution with or without acids or halide salts. The halide salts, when utilized, provide control of the activity of the bromine. The process is advantageously adapted for activating the thermoplastic material where it is intended that it serve as a substrate for use in accepting copper plating, as in printed circuit board manufacture.
Abstract:
Technique utilisant soit un logiciel particulier avec un microprocesseur (17) ou un ordinateur ou un circuit câblé numérique ou analogique, permettant de déterminer, à partir de quelques échantillons d'amplitude dérivés d'un signal analogique à des intervalles de temps égaux, la forme de l'onde (21) et de l'afficher. La pente de la forme d'onde analogique de chaque échantillon est calculée à partir de l'amplitude des deux échantillons obtenus de la forme d'onde (21) précédant immédiatement un échantillon donné et des deux échantillons suivant immédiatement l'échantillon donné. Une pente de la forme d'onde analogique intermédiaire à chaque intervalle d'échantillonnage est ensuite calculée à partir de ces informations, ce qui permet d'obtenir un calcul final de l'amplitude d'un nombre sélectionné de points pendant l'intervalle d'échantillonnage. Les amplitudes d'échantillons ainsi obtenues et les amplitudes intermédiaires calculées sont ensuite combinées dans un affichage (19) donnant la reconstruction de la forme d'onde analogique originale.
Abstract:
A marine drive system utilizing a multiphase induction motor (15) for driving the propulsion propeller of the drive from a battery power supply. The number of phases defined by the motor stator winding, in the preferred embodiment of the invention, is at least four (18a-18m) and the windings are excited by a corresponding plurality of inverters (14a-14d) connected one each to the windings from the power supply batteries for exciting the windings. Harmonic currents in the windings are effectively suppressed by providing the drive motor in a configuration having high leakage reactance in the stator. The windings may be arranged as multiples of three-phase windings. In the illustrated embodiment, the inverters are arranged to define three-phase half-bridge inverters for exciting three sets of three-phase windings of the motor stator.
Abstract:
Un circuit de commutation de transistor permet d'effectuer la commutation d'un transistor de puissance (28) d'un état sous tension vers un état hors tension à des vitesses élevées avec une dissipation minimum de puissance et sans rencontrer de charges disruptives secondaires dans le transistor de puissance. Le circuit de commutation du transistor comprend un transformateur (36) ayant un enroulement secondaire (35) connecté à la base (30) du transistor de puissance (28) et un enroulement primaire (49) connecté à une logique de commutation (38), le transformateur (36) assurant une isolation galvanique entre le transistor de puissance (28) et la logique de commutation (38). La logique de commutation (38) comprend un premier commutateur (50) et un second commutateur (52). Lorsque le premier commutateur (50) est sous tension et le second commutateur (52) est hors tension, l'enroulement secondaire (35) du transformateur (36) développe un courant de base positif appliqué au transistor de puissance (28), mettant ainsi le transistor sous tension. Pour unifier la commutation du transistor (28) sur son état hors circuit, le premier et le second commutateurs (50, 52) sont tous les deux en circuit, ce qui fait cesser la conduction de courant par l'enroulement secondaire (35) pour permettre aux porte-charges collecteurs du transistor (28) de se recombiner. Après que les porte-charges collecteurs sont recombinés de manière suffisante, cette recombinaison étant détectée par un circuit de détection de saturation (62), le premier commutateur (50) est mis hors circuit, le second commutateur (52) restant sur "on" de sorte que l'enroulement secondaire (35) développe un courant négatif appliqué sur la base du transistor de puissance (28), mettant le transistor (28) rapidement sur "off". Le circuit de commutation du transistor comprend en outre des moyens pour limiter la tension d'émission de base du transistor et des moyens pour remettre à zéro rapidement le noyau du transformateur.
Abstract:
Gas diffusion electrodes (12) and gas generating or consuming electrochemical cells (10) utilizing the same are disclosed. The electrode (12) comprises an electronically conductive and electrochemically active porous body defining respective gas and electrolyte contacting surfaces (15, 17) with a substantially gas impermeable material filling at least a portion of the pore volume of said body so as to prevent gas passage therethrough. The material comprises an electrolyte-insoluble, ionomeric ionically conductive hydrophilic hydrogel formed by coprecipitation between at least two precursor polymers.
Abstract:
Gas diffusion electrodes (12) and gas generating or consuming electrochemical cells (10) utilizing the same. The electrode (12) comprises an electronically conductive and electrochemically active porous body defining respective gas and electrolyte contacting surfaces (15, 17), with an ionomeric ionically conductive membrane disposed over the electrolyte contacting surface (17). The membrane comprises a hydrophilic anion exchange resin which is substantially impermeable to gas flow.
Abstract:
A system (10) and a method useful in the formation of electrodes for use in electrochemical cells. The system includes a pair of conductive end electrodes (12) (14) spaced apart from one another and situated in an aqueous electrolyte (16). A pair of precursor electrodes (20) (22) are placed in the electrolyte (16), between the end electrodes (12) (14). Each of these precursor electrodes (20) (22) comprise a material (24) to be selectively reduced or oxidized disposed on a conductive substrate (26). The precursor electrodes (20) (22) are in a configuration substantially precluding contact between the electrolyte (16) and the substrates (26) thereof. The end electrodes (12) (14) and the precursor electrodes (20) (22) are in electrical contact with a power supply (27) to effect a current flow in the electrolyte thereby reducing or oxidizing the material (24) of the precursor electrodes (20) (22) to substantially maintain the dimensions thereof during the electrode charging process. The system includes a separator (36) effective in permitting the electrolyte (16) to contact the precursor and terminal electrodes.
Abstract:
A process for pressure bonding a consumable, reactive metal anode plate (12) to a bipolar plate (10) for use in an electrochemical cell. Pressure is applied to the anode plate in a given direction progressively over a given area (Figs. 2A-2C) to mechanically bond that area of the anode plate to the bipolar plate, thereby forcing out any trapped air from in between the plates.
Abstract:
Selected saturated organic polymers having multiple ether linkages are useful in at least partially passivating the electrochemical reaction occurring at the reactive metal anode of an electrochemical cell using an aqueous electrolyte. Useful polymers are characterized as having a molecular weight in the range of about 100 to 1000 Daltons, as being at least partially miscible with the aqueous electrolyte, chemically inert with respect to the anode, cathode and electrolyte, and having an atomic ratio of carbon in the polymer to oxygen in the ether linkages of about 1 to 5:1.