Showing papers by "Westinghouse Electric published in 1991"

Vector analysis and control of advanced static VAr compensators

Abstract: The advanced static VAr compensator (ASVC) is based on the principle that a self-commutating static inverter can be connected between three-phase AC power lines and an energy-storage device, such as an inductor or capacitor, and controlled to draw mainly reactive current from the lines. This capability is analogous to that of the rotating synchronous condenser and it can be used in a similar way for the dynamic compensation of power transmission systems, providing voltage support, increased transient stability, and improved damping. The authors present a simplified mathematical model of the ASVC that has made it possible to derive the transfer functions needed for control system synthesis. The resulting control system designs are briefly outlined and further analysis is presented to show the behaviour of the ASVC when the line voltage is unbalanced or distorted. The analysis is based on a vectorial transformation of variables, first described by R.H. Park (1928) for AC machine analysis, and later, using complex numbers, by W.V. Lyon (1954) in the theory of instantaneous symmetrical components.

Conducting polymers

Abstract: Several polymers have been synthesized that have the ability to conduct electricity. Several companies and universities are actively investigating these polymers to develop industrially useful products. The authors give an overview of the work performed on conducting polymers and discuss the possible applications of such materials. Attention is given to applications of these materials in such areas as electric power equipment, microelectronics, batteries, and microtools. >

Effect of cu-o layer spacing on the magnetic field induced resistive broadening of high-temperature superconductors

Abstract: For H‖c-axis, the magnetic field induced broadening of the resistive transitions of high-Tc superconductors (HTS) is shown to depend strongly on the Cu-O layer spacing. For the highly anisotropic HTS, we show experimental evidence that flux motion results from a thermally activated crossover from three dimensional (3D) vortex lines to 2D independent pancake-like vortices in the Cu-O layers, which is intrinsic to the material and occurs when kBT exceeds the Josephson coupling energy of these layers. At low temperatures, however, thermally activated conventional depinning (which can be sample dependent) or melting in the uncoupled 2D Cu-O layers is also required for flux motion. For YBa2Cu3O7, this dimensional crossover does not occur belowHc2, presumably because the conducting Cu-O chains short-circuit the Josephson interlayer coupling, leading to better superconducting properties in a magnetic field. These results show that strong interlayer coupling is a key to finding good alternatives.

Dual mode electronic identification system

Abstract: A dual mode electronic identification system using a tag which has a RF receiver and transmitter contained therein. In the first mode the tag responds to an interrogation signal by transmitting identification data to the interrogator. In the second mode the tag periodically transmits an identification beacon signal to a directional sensing antenna which uses the signal to compute the position of the tag. The power supply for the tag operates from an internal battery or from power received from a portal signal via a tag receiving antenna. The battery can be automatically turned off when the tag is in the portal area and the unit can be shifted into the battery operated beacon mode when the tag is removed from the portal area.

Comparison of bacteria from deep subsurface sediment and adjacent groundwater.

Abstract: Samples of groundwater and the enclosing sediments were compared for densities of bacteria using direct (acridine orange direct staining) and viable (growth on 1% PTYG medium) count methodology. Sediments to a depth of 550 m were collected from boreholes at three sites on the Savannah River Site near Aiken, South Carolina, using techniques to insure a minimum of surface contamination. Clusters of wells screened at discreet intervals were established at each site. Bacterial densities in sediment were higher, by both direct and viable count, than in groundwater samples. Differences between direct and viable counts were much greater for groundwater samples than for sediment samples. Densities of bacteria in sediment ranged from less than 1.00×106 bacteria/g dry weight (gdw) up to 5.01 ×108 bacteria/gdw for direct counts, while viable counts were less than 1.00×103 CFU/gdw to 4.07×107 CFU/gdw. Bacteria densities in groundwater were 1.00×103–6.31×104 bacteria/ml and 5.75–4.57×102 CFU/ml for direct and viable counts, respectively. Isolates from sediment were also found to assimilate a wider variety of carbon compounds than groundwater bacteria. The data suggest that oligotrophic aquifer sediments have unique and dense bacterial communities that are attached and not reflected in groundwater found in the strata. Effective in situ bioremediation of contaimination in these aquifers may require sampling and characterization of sediment communities.

Molded case current limiting circuit breaker

Abstract: A molded case circuit breaker having current limiting capabilities is dimensionally optimized for relatively smaller frame size circuit breakers The handle yoke is supported with rollers thereby allowing the crossbar to be disposed in the space normally utilized for the handle yoke pivot axis A clinch joint arcer assembly with a plurality of arcing contact arms, each pivotally connected by a clinch joint to a pivotally mounted main contact arm permits additional main contact arms to be provided in the same space normally occupied by the arcing contact arms alone Additionally, arcing contact spring housings protect the arcing contact springs from deterioration due to corrosive ionizing gases generated during interruption A positive off link assembly prevents the operating handle from being placed on an OFF position when the main contacts are welded together and transfers the force applied to the operating handle to the upper link to allow the weld to be broken Lastly, a reversible barrier in one of the sidewalls allows in one position circuit breaker auxiliaries, located in the outside pole compartments, to communicate with the operating mechanism and the operating handle For circuit breakers without auxiliaries, the barrier acts as an interphase gas barrier

Millimeter wave and infrared sensor in a common receiving aperture

Abstract: The present invention is an integrated millimeter wave (MMW) and an infrared (IR) common aperture sensor employing a common primary reflector for infrared and millimeter wave energy. An active transmitter/receiver millimeter wave horn assembly located at the focus of the primary mirror transmits and receives millimeter wave signals off the primary reflector. A selectively coated dichroic element is located in the path of the millimeter wave energy on the axis between the feed and the primary reflector. The dichroic element reflects infrared energy from the primary reflector to a focal point and at the same time transmits and focuses millimeter wave energy. An optical system relays the infrared energy to a focal plane behind the primary mirror. The dichroic element transmits and focuses millimeter wave energy without significant attenuation such that optical and millimeter wave energy may be employed on a common boresight. Improvements in the feed assembly include a four channel waveguide structure capable of azimuth and elevation determination in sum and difference configurations. A baffle and cold stop shields the optical system from unwanted infrared radiation. Electrical transmit and receive circuitry and a correction circuit provide high probability of detection and low false alarm rate.

Solid state event recorder

Abstract: A solid state event recorder having particular application to railroad locomotives has a plurality of interface modules to allow the collection of desired data over a period of time. Radio downloading of the data provided by a telemetry transmitter to wayside receivers is the primary way of downloading data. Alternative data downloading are provided by a removable memory module, a portable wireless data extractor and a laptop computer. The removable memory module is provided with its own backup battery power supply but normally derives its power from an inductive coupling to the solid state recorder. Data is read into the removable memory module from the solid state recorder via an inductive coupling, and data is read out of the removable memory module to the telemetry transmitter via another inductive coupling. Both the portable wireless data extractor and the laptop computer are used for maintenance purposes. The solid state recorder can be configured in a variety of ways and connected together as master and slave. For example, one recorder, acting as a master and functioning as the primary of operational recorder, can be connected to a second recorder, acting as a slave time synchronized with the first recorder. This second recorder can serve as a maintenance recorder for collecting long term data and trouble shooting a particular locomotive.

Microwave film bulk acoustic resonator and manifolded filter bank

Abstract: A film bulk acoustic resonator (FBAR) configured as a coplanar transmission line structure. A film resonator formed over an opening in a substrate is connected to associated circuitry by one or more transmission lines formed on the substrate. The coplanar ground plane of this structure provides a simple mechanism for providing a true ground connection to the resonator without the need for vias passing through the substrate. The transmission line connection eliminates the need for wirebonds, thus simplifying fabrication, allowing the device to be more easily modified for computer simulation, and facilitating the operation of the device at microwave frequencies. Embodiments for standard, stacked, and 3-port FBAR's as well as a filter bank consisting of a plurality of coplanar 3-port FBAR's, are described.

Notch radiator elements

Abstract: A planar dielectric substrate supports a stripline conductor therein. A conductive housing has one or more recesses for receiving a dielectric and a conductive cover is mountable over the dielectric in contact with the housing to enclose the dielectric and isolate the stripline from adjacent structures. The housing and cover have aligned slots disposed on opposite sides of the dielectric and transverse to the stripline for providing coupling of signals between the stripline and the slot. An aperture is formed in the housing in communication with the slot. Other embodiments of the invention include impedance matching means for either or both of the stripline and the aperture for optimizing the efficiency measured in terms of VSWR of the radiator.

Transmission line dynamic impedance compensation system

Abstract: A series impedance compensation system for a set of transmission lines which are used for electrical power transmission, with these parallel lines being protected from the transient faults and dynamic subsynchronous oscillation problems. These problems can become aggravated by the introduction of capacitor banks which thus serve as only a partial solution to the disturbances of transient faults during conventional recovery modes of operation. The impedance compensation system is coupled in series to each transmission line to dynamically balance the inductor impedance on the transmission line, responsive to demand, by injecting a voltage component determined to be optimized substantially at quadrature leading or lagging phase angles (±90°) with respect to the transmission line voltage and current components. The impedance compensation system includes a circuit based solid-state switching power converter with self-commutating thyristor or GTO semiconductor switches connected in a parallel shunting arrangement with reverse poled or freewheeling diodes. This is done in order to provide either an absorptive component or a generated component of output pole voltage carrying a 90° segment of the output current in each cycle, as this provides dynamic stability without fostering subsynchronous resonance.

Electronic identification tag interrogation method

Abstract: An electronic identification tag interrogation method is provided in which a portal transmits an interrogation signal which is received by an electronic identification tag within its field of range. The interrogation signal includes an address which requests a response from every tag having an address greater than or equal to the address of the signal. If more than one reply is received by the portal, the interrogation address is bisected and the interrogation signal is retransmitted. The interrogation address is successively bisected until a single response is isolated. When a single response is isolated, communication is directed between the portal and the identification tag and the interrogation system is reset to isolate and identify any remaining tags.

Electrical circuit breaker operating handle block

Abstract: Apparatus is provided for an electrical circuit breaker for preventing the handle thereof from being moved to the OFF position when the electrical contacts of the circuit breaker are welded closed. This apparatus mechanically limits the travel of the operating handle so that it may not be moved to the OFF position when the electrical contacts are closed. This restrictor apparatus as it is called is mechanically connected to, but out of direct contact with the handle arm of the circuit breaker. The mechanical linkage between the operating handle and the contact arm of the circuit breaker includes a projection. During the foregoing condition, the projection will interact with a crossbar assembly for the contact arm of the circuit breaker. If an attempt is made to move the handle to the OFF position while the contacts remain welded closed, the crossbar assembly is oriented with respect to the path of travel of the projection to prevent the projection from movement past the crossbar assembly and thus to prevent movement of the handle to the OFF position. If, however, the contacts are open as an attempt is made to move the handle to the OFF position, the crossbar assembly will become disposed differently relative to the path of travel of the projection such that the projection will freely move past the crossbar assembly thus allowing the handle mechanism to be moved completely to the OFF position.

Application of a fast tool servo for diamond turning of nonrotationally symmetric surfaces

Abstract: The fabrication of nonrotationally symmetric surfaces by diamond turning requires tool actuation at a bandwidth significantly higher than the rotational frequency of the surfaces. This requirement cannot be met by standard slide drives due to their large mass and consequent low natural frequency. This articles describes the development of a laboratory-scale diamond-turning machine with piezoelectric-driven fast tool servo. The capability of this apparatus will be demonstrated for high-speed features such as sine wave, square wave, and ramp-shaped surfaces. Also described is the implementation of this fast tool servo on a commercial diamond-turning machine. Several nonrotationally symmetric surfaces have been machined, and their images are included.

The technological gender gap: Evidence and recommendations for educators and computer-based instruction designers

Abstract: The term “technological gender gap” refers to the idea that males and females have different technology-related attitudes, behaviors, and skills This article reviews the mounting evidence documenting the existence of a gender gap, which, if ignored, could render large numbers of female students unprepared to meet the technological challenges of the future Recommendations for ameliorating the technological gender gap are presented for educators and computer-based instruction (CBI) designers who are interested in providing equitable educational opportunities for male and female students

Electrochemical cell apparatus having an integrated reformer-mixer nozzle-mixer diffuser

Abstract: An electrochemical apparatus (10) is made having a generator section (22) containing electrochemical cells (16), a fresh gaseous feed fuel inlet (28), a gaseous feed oxidant inlet (30), and at least one hot gaseous spent fuel recirculation channel (46), where the spent fuel recirculation channel (46), passes from the generator chamber (22) to combine with the fresh feed fuel inlet (28) to form a reformable mixture, where a reforming chamber (54) contains an outer portion containing reforming material (56), an inner portion preferably containing a mixer nozzle (50) and a mixer-diffuser (52), and a middle portion (64) for receiving spent fuel, where the mixer nozzle (50) and mixer-diffuser (52) are preferably both within the reforming chamber (54) and substantially exterior to the main portion of the apparatus, where the reformable mixture flows up and then backward before contacting the reforming material (56), and the mixer nozzle (50) can operate below 400°C.

Electrochemical cell apparatus having an exterior fuel mixer nozzle

Abstract: An electrochemical apparatus (10) is made having a generator section (22) containing electrochemical cells (16), a fresh gaseous feed fuel inlet (28), a gaseous feed oxidant inlet (30), and at least one hot gaseous spent fuel recirculation channel (46), where the spent fuel recirculation channel (46), a portion of which is in contact with the outside of a mixer chamber (52), passes from the generator chamber (22) to combine with the fresh feed fuel inlet (28) at the entrance to the mixer chamber, and a mixer nozzle (50) is located at the entrance to the mixer chamber, where the mixer chamber (52) connects with the reforming chamber (54), and where the mixer-diffuser chamber (52) and mixer nozzle (50) are exterior to and spaced apart from the combustion chamber (24), and the generator chamber (22), and the mixer nozzle (50) can operate below 400°C.

Electrochemical cell apparatus having combusted exhaust gas heat exchange and valving to control the reformable feed fuel composition

Abstract: An electrochemical apparatus (10) is made having a generator section (22) containing electrochemical cells (16), a fresh gaseous feed fuel inlet (28), a gaseous feed oxidant inlet (30), gaseous spent fuel recirculation channels (46), and hot combusted exhaust gas exit channels (45), where the spent fuel recirculation channel (46) passes from the generator chamber (22) to combine with the fresh feed fuel inlet (28) at a circulation and mixing apparatus (50), where a reformable fuel mixture channel (51) passes between the mixing apparatus and reforming chamber (54) containing a reformable material, where a portion of the hot combusted exhaust gas exit channel (45) surrounds the reforming chamber (54), and where the fresh feed fuel inlet has a by-pass channel (62) into the gaseous spent fuel recirculation channel (46), said by-pass channel having valving to control fresh fuel feed flow to the gaseous spent fuel recirculation channel.

Performance Deterioration in Industrial Gas Turbines

Abstract: This paper describes the most important factors affecting the industrial gas turbine engine performance deterioration with service time and provides some approximate data on the prediction of the rate of deterioration. Recommendations are made on how to detect and monitor the performance deterioration. Preventative measures, which can be taken to avoid or retard the performance deterioration, are described in some detail.Copyright © 1991 by ASME

Low inductance cantilever switch

Abstract: An apparatus is disclosed for providing an electrostatically actuated mechanical switch utilizing a cantilever beam element fabricated by solid-state microfabrication techniques. The apparatus reduces the required pull down voltage and lowers the switch inductance by separating the pull down electrode and contact pad. The pull down electrode is placed further away from the fulcrum of the cantilever beam then the contact pad to optimize the mechanical advantages which allow for a reduced pull down voltage. The contact pad is placed closer to the cantilever fulcrum to reduce the associated switch inductance. The gap between the contact pad and the cantilever beam is less then the gap between the pull down electrode and the cantilever beam to insure that the cantilever makes first contact with the contact pad.

Low- and high-temperature superconducting microwave filters

Abstract: Stripline and microstrip filters at X-band were designed and fabricated using low- and high-temperature superconductors in quarter-wave, parallel-coupled section configurations. Low-temperature superconducting niobium thin films, deposited on single-crystal sapphire, were used to build to six-pole stripline filters with adjacent passbands and approximately 3 dB crossovers and 1.2% bandwidth. Four- and six-pole microstrip filters were made with in situ epitaxial YBa/sub 2/Cu/sub 3/O/sub 7/ (YBCO) films on LaAlO/sub 3/ substrates. All the YBCO filters showed 77 K passbands with clean skirts and high out-of-band rejection. The six-pole filters had adjacent passbands with -28 dB crossovers and 1.5% bandwidth. >

Factors affecting service utilization for depression in a white collar population.

Abstract: The present study examines rates of mental health service utilization among depressed individuals in a large white collar cohort Clinical and psychosocial features of a recent depressive episode, as well as preexisting psychiatric and psychosocial characteristics, are examined for their ability to distinguish between individuals who (a) did and did not seek help during their episode and (b) chose to consult one professional source rather than another Results showed that approximately one-third of the sample sought professional help Respondents consulting mental health specialists were more clinically impaired and had poorer work performance and fewer psychosocial assets than both those consulting nonpsychiatric physicians and those seeking no help Respondents in the latter two groups were indistinguishable from one another on many of the assessed variables

Lateral field FBAR

Abstract: This invention is a design for lateral field film bulk acoustic resonators (LF-FBAR). All electrodes in this design are located on one surface of the piezoelectric material, thereby simplifying manufacturing and improving performance. The gap between electrodes is limited to a specified dimension to maximize the efficiency of the device. Single and multi-pole devices are described. Barium magnesium fluoride and lithium niobate are specified as the piezoelectric material for high frequency applications.

Method for training material evaluation with method of EEG spectral estimation

Abstract: The invention is a method and apparatus in which student EEG measurements are made during the videotaped presentation of training materials. Alpha (8-12 Hz) and beta (16-24 Hz) activity present during segments of the material directed to a learning objective are used to determine attention and cognitive activity during the training material. An increased level of attention relates to increased understanding of the material. An increased level of cognitive activity relate directly to incorrect understanding of the material. Evoked potential responses are also measured in response to multiple choice questions on the learning objections presented subsequent to the training materials. A difference between midterm responses for correct and incorrect answers measures correct understanding of the subject matter of the multiple choice question. Comparing the alpha, beta and evoked potential results for a learning objective validates the indication of effectiveness if the results correlate. To evaluate the EEG spectra for varying length recorded signal segments and between individuals with different magnitude responses, the EEG signals are normalized and interpolated to the same length before a windowed FFT is performed the peaks in the FFT are then found.

Circuit breaker with welded contacts

Abstract: The handle of a circuit breaker is blocked from movement to the off positiion, when the contacts are welded closed, thereby preventing rotation of the common cross-bar on which contact arms carrying the movable contacts are mounted, by an interlock which includes radial extensions on the arms of a pivoted handle yoke which radially engage projections on the cross-bar.

Frame based office space dividing system

Abstract: An office space dividing system comprising office furniture components in combination with a plurality of structural rectangular frames having openings which may be left open or closed in varying degrees with a wide variety of fill options, which may be readily changed, to create the desired degree of privacy. The system combines the advantages of a full height office partition system with lockable doors, and an open plan panel system. An enlarged cornice accommodates both wiring and ambient lighting, with a cornice to ceiling space being left open or closed with a clerestory, as desired, without compromising the ability to install lighting fixtures and wiring. The rectangular frames have mitered stiles which, when assembled with other frames, and/or mitered fill pieces, create columns defining vertical wire ways which communicate with cornice wiring, work surface height wiring, and/or base wiring, as desired.

Temporal relaxation of nonequilibrium in Y-Ba-Cu-O measured from transient photoimpedance response.

Abstract: Nonequilibrium in Y-Ba-Cu-O thin films biased with a dc current is photoinduced by exposure to 300-fsec 2-eV laser pulses. The photoinduced nonequilibrium transients were measured in the superconducting, transition, and normal states occurring between 7 and 200 K. The photoabsorption produced temporal changes in the sample's impedance, which manifest themselves as transient voltage signals occurring across the samples during the nonequilibrium's relaxation process. At and above {ital T}{sub {ital c}}, the observed photoresponse is thermal. Below {ital T}{sub {ital c}}, a quantum response is obtained corresponding to changes in the Cooper-pair populations. In the zero-resistance superconducting state, a positive signal corresponds to quasiparticle generation and a negative signal corresponds to quasiparticle recombination.

Direct digital FM waveform generator for radar systems

Abstract: A linear FM waveform generator employs direct digital synthesis and includes a digital linear FM signal generator, a digital-analog converter, and a sampler means. The linear FM waveform generator includes a frequency slope register coupled to a first stage integrator which in turn is coupled to a second stage integrator, all of which operate off a system clock. The output signal from the second stage integrator represents phase as a quadratic function of time. A stored sine look-up table is referenced to generate an output digital signal representing amplitude as a function of time. The output digital signal is converted to an analog linear FM waveform which in turn is coupled to a sampler that includes a step recovery diode and a fast switch. The sampler aperture is sufficiently small that the sampler output linear FM waveform includes base and higher harmonic spectra with amplitude attenuation small enough to enable a third or higher harmonic spectra to be used for generation of the output linear FM waveform. The sampler output is filtered to pass a higher harmonic spectra which is directly coupled to output multiplication and filter circuitry.

Polymeric enclosure for electrical apparatus

Abstract: A non-metallic enclosure for electrical apparatus has a housing and cover with a door pivotably mounted on the cover. A hood is attached to the housing such that when the door is attached to the cover and the cover is attached to the housing at least one pivotable connector will be behind the hood so that the door can only be nondestructively removed by removing the cover from the housing. Electrically conductive connectors and resilient snap-in members are preferably molded into the housing to secure bus bars and neutral bars to the housing.