Showing papers on "Insulator (electricity) published in 1983"

Operation of chemically sensitive field-effect sensors as a function of the insulator-electrolyte interface

Abstract: All chemical sensors based upon the field-effect principle share a common quality. Their measurable properties can be described in terms of a flat-band voltage. The various terms in the expression of the flat-band voltage are described and discussed, and in particular the voltage drop at the insulator-electrolyte interface. It is shown that this voltage drop depends on the pH of the electrolyte and is determined by two parameters, the pH at the point of zero charge, and a sensitivity parameter which is introduced in this paper. These parameters are obtained from the site-dissociation model of the insulator-electrolyte interface, combined with the Gouy-Chapmann-Stern theory of the electrical double layer at this interface. The theoretical description is used to interpret experimental results obtained from insulators with widely different properties, namely SiO 2 and Al 2 O 3 .

Solid-state image pickup device

Abstract: PURPOSE:To obtain an image pickup device which is driven at a low voltage, by making a characteristic of optical current of a photoelectric converting element to an applied voltage formed on an insulator substrate flat at a low voltage region. CONSTITUTION:Band shaped electrodes 2 are formed on the insulator substrate 1, one end is formed with a photo conductive thin film 3, a transparent conductive thin film 4 is formed on the film 3 and the thin film 4 is connected to a bias power supply 5. The other end of the electrodes 2 is connected to a switching circuit 6 fitted on the substrate 1 with wire bonding 7 or the other methods. In the solid-state image pickup device like this, the optical current to the intensity of light incident through the film 4 is generated in the film 3. The voltage versus optical current characteristics of the film 3 is made flat at the low voltage region, allowing to drive the pickup device at a low voltage.

Minimum Flashover Voltage of Iced Insulators

Abstract: Experimental studies were performed in a 48×28×35 m3 cold room with a HV transformer of 124 kVA, 120 kV Atmospheric ice was accreted on a vertical string of three types of insulators: a classic glass insulator and two long-rod synthetic insulators The results obtained show that flashover occurs at the lowest voltage with hard rime formed at -12°C with a density of 087 With hard rime it is found that the minimum flashover voltage of the glass insulator used is about 40% of that of a wet insulator The minimum flashover voltage measured without applied voltage during the icing period is higher than that obtained with voltage applied during icing Except for very light icing conditions, the length of icicles is a less accurate parameter for the measurement of the severity of the icing than the thickness of ice accreted on a monitoring conductor For clean iced insulators, it is found that the minmum flashover voltage decreases with increasing thickness of ice up to 2 cm In addition, the results obtained show that the minimum flashover voltage is linearly proportional to the arc path on iced insulators, ie the sum of the spacings and the leakage distance of one clean insulator It is shown that the effect of the thickness of ice on precontaminated iced insulators, decreases with increasing degree of the contamination

Window assembly with light transmissive insulator and method

Abstract: A window assembly which includes a light transmissive heat insulator. The insulator is comprised of a high loft body of bonded together synthetic staple fibers and a plastic film adhered thereto. The window assembly with its insulator has a heat resistance R value of at least about 3 while also being substantially transmissive to incident light.

High voltage insulators

Abstract: A method of manufacturing an improved electrical high voltage coated insulator is described. The method involves applying and curing a one-part, room temperature curable silicone composition to the surface of an insulator, the insulator surface having a minimum designated arc resistance. The silicone composition is the product obtained by mixing in the substantial absence of moisture a specified polydimethylsiloxane fluid containing hydroxyl radicals, finely divided aluminum hydroxide filler, a silane of the formula R b Si(ON═X) 4-b and an optional condensation catalyst. The coating cures on exposure to atmospheric moisture to produce a surface adhered onto the insulator that resists the development of leakage currents and flashover failure upon exposure to electrical stress, moisture, contamination, and other outdoor weathering stresses.

Modification of electric field at the solid insulator–vacuum interface arising from surface charges on the solid insulator

Abstract: The surface of a solid insulator in vacuum (and in a high gas pressure) becomes electrically charged when subjected to a high voltage stress. The surface charge density is proportional to the applied voltage. The magnitude of the surface charge density depends on the secondary electron emission characteristic, the geometrical shape, and the material of the insulator. The field enchancement, contributing to a lower withstand voltage of solid insulators in vacuum (and in high pressure gases), due to the presence of surface charge is computed along the surface of the solid insulator and at the triple electrode‐solid insulator‐vacuum junction near the anode and cathode. Different patterns of surface charge density distribution has been considered in order to evaluate their effects on the field enhancement. The polarity, the magnitude and the shape of the distribution of the surface charge density has been found to have a considerable effect on the field enhancement. The observed influence of the charge distri...

Thin film magnetic head

Abstract: PURPOSE:To improve high frequency characteristics by permitting a submagnetic layer to have higher magnetic permeability than a main magnetic layer in a high frequency range. CONSTITUTION:On a substrate material 6 as the slider of a thin-film magnetic head, the lower magnetic pole 11 consisting of a main magnetic layer 8 and a submagnetic layer 9 is formed with an insulating layer 5 between and then the coil 3 consisting of an insulating layer 4 and an electric onductor for specifying a gap G is formed. The coil 3 is charged with an insulator 10 for the elimination of a step and electric and magnetic insulation and covered with the upper magnetic pole consisting of two layer films, i.e, submagnetic layer 12 and main magnetic layer 11. The submagnetic layers 9 and 12 have higher magnetic permeability than the main magnetic layers 8 and 11 at least in a high frequency signal magnetic field area and are positoned on a side facing the coil 3, thereby forming the gap G.

Multiple contact header assembly

Abstract: A header assembly is provided for the electrical connection of printed circuit boards to cables or other boards The assembly includes an insulator having an array of male pin members mounted thereto Each pin member comprises a plastic post to which a pair of electrical contacts is secured

Electric Surface Strength and Surface Deterioration of Thermoplastic Insulators in Vacuum

Abstract: Investigations have been made of various factors which effect the surface flashover strength across thermoplastic insulators in vacuum. The factors studied, for ac and dc excitation, included the dependence of flashover voltage on specimen length, metallization of the insulator ends, specimen conditioning under dc and ac voltages, and residual gas pressure. The influence of the number of sequential flashovers on the flashover voltages and on the surface deterioration of polymethylmethacrylate, tetrafluoroethylene, and polyethylene samples, in vacuum, has also been determined. Tree tracks were examined under an electron microscope to determine their growth and characteristics at different stages of the experiment.

Electrically insulated heat sink assemblies and insulators used therein

Abstract: An insulator used in connecting heat generating electrical components to heat sinks. Fasteners which include insulators of the present invention include flexible engaging means for preassembling an insulating washer portion to a conductive fastener element. The insulators may be made of high performance plastic material or of a coated metal. The fasteners used with the insulators preferably have integral spring washers to maintain thermal conductivity between the components and the associated heat sinks. The insulator preferably have integral bosses which prevent arcing between the conductive fasteners and the heat sinks.

Coil insulating method for rotary electric machine

Abstract: PURPOSE:To improve the thermal conduction and to improve the reliability by coating putty insulator on the end of a mica insulating layer to form a uniform powder insulating layer. CONSTITUTION:A mica insulating layer 6 of mica tape is coated in the range of a coil end including slots at a sole coil time. Then, a putty insulator 8 made of thermosetting resin such as epoxy resin is coated to cross over between the coil conductor and the mica insulator at the end of the layer 6. In order to harden the insulator 8 and to improve the powder painting on the coil end, the coil is preliminarily heated, dipped in a fluid dipping tank to the range to be suitably lapped to the layer 6 at the coil end, thereby forming a powder insulating layer7. The insulator 8 may use a material which contains a filler of good thermal conductivity such as alumina in thermosetting resin.

Influence of Radius of Curvature, Contact Angle and Material of Solid Insulator on the Electric Field in Vacuum (and Gaseous) Gaps

Abstract: The insulation strength of a vacuum gap bridged by a solid insulator is lower than that in the absence of the solid insulator. The triple junction formed by the solid insulator, electrode, and vacuum in vacuum devices (or a gas in high-pressure apparatus) has a critical influence on the withstand voltage level of the insulating gap. The electric field is calculated using the charge simulation technique at the triple junction as a function of the junction geometry. The dependence of the field is studied for a varying contact angle a between the solid insulator and the electrode in the range 0 to 90°, for a varying ratio r/D of the radius of curvature r of the rounded edge of the solid insulator at the junction to the length of the insulator D, at a fixed r/D and varying r and D and for different practical insulator materials having relative dielectric permittivities ?£ in the range 2.1 to 12000. It has been found that the electrical field at the electrode-solid insulatorvacuum junction has a strong dependence on both the contact angle and the solid insulator material. The tangential and normal components of the electric fields are determined at the solid insulator-vacuum boundary and away from the boundary both inside the solid insulator and in the vacuum. Large enhancements in the electric field at the triple junction are found. The effects of the parameters ?, r, and ?r on the with-stand voltage of the insulating gap are discussed.

Temperature-humidity surveillance equipment

Abstract: A surveillance device is provided for a container filled with a fluid or the like and it includes an electrical resistance wire for temperature control and a hygroscopic insulator for control of humidity. For this purpose, an electrical conductor wire is disposed substantially in parallel to the resistance wire in its longitudinal direction, which forms together with the resistance wire and the hygroscopic insulator a single unit multifunctional temperature-humidity measurement cable. At least two essentially parallel running wire conductor strands are provided for a potential-free and mutually noninterfering measurement. The hygroscopic insulator is disposed between the wire conductor strands. The cable sensor can be employed in power and steam plants and in nuclear installations.

The Development of Theories of the Electrical Breakdown of Gases

Abstract: In its normal state a gas is almost a perfect insulator and in everyday life is used as such. Under certain conditions, however, when an electric field is established between two electrodes, of intensity dependent upon their geometry and the gas properties, the gas can become an almost perfect conductor. The transition from insulating to conducting states is an electrical discharge known as the electrical breakdown of the gas or spark. An outstanding feature of this process is that for most geometries the interelectrode potential difference at which this transition occurs can be highly critical, and electrical technology as we know it is dependent on this fact. This critical potential difference is known as the breakdown potential VS of the gas for that particular electrode system. In practice, it is the lowest potential difference at which breakdown can occur providing initiating electrons are present.

Salient pole rotor with amortisseur winding

Abstract: A unique design and construction is presented for the rotor of a dynamoelectric machine. The rotor is comprised of two end plates, bar means for holding the end plates together, a stack of pole laminations, electrical conductors wrapped about the laminations and an insulator means. The end plate contains apertures about its periphery such that the rotor can be balanced about two axis perpendicular the rotor axis of rotation by inserting masses/weights into the apertures. The insulator means electrically insulates the electrical conductors from the ends of the stack laminations, the rotor end plates and the rotor shaft. The insulator means by its unique shape further acts as a guide to position electrical conductors about the laminations during pole winding. In one embodiment the insulator means acts as a thermal insulator protecting electrical conductors when the bar means are welded to the end plates.

High Resolution Studies of the Electrical Breakdown of Soil

Abstract: The results of small scale experimental measurements of the behavior of soil stressed with high electric fields in geometries designed to allow measurement of either the current distribution along the center conductor or the voltage along a growing streamer are reported. Data are obtained which are important for development of streamer initiation and propagation models.

Magnetic field stabilized transferred arc furnace

Abstract: A DC electric arc furnace utilizing a magnetic field stabilized electric arc. A DC magnetic field is employed to cause rotation and angular deflection of the electric arc about the surface of the melt. In one embodiment the DC magnetic field is induced by a field coil. In an alternate embodiment a specially shaped electrical insulating member can be positioned in the melt so that the flow of arc current through the melt creates a magnetic field which is used to cause arc rotation. In a further embodiment a plurality of coil sets are located about the periphery of the furnace are used in conjunction with current reversing and current sequencing means to create a rotating DC magnetic field which is used to rotate the arc. A ceramic electric insulator can also be supplied in the chamber of the furnace to prevent arc fixation in the region wherein the DC magnetic field is substantially parallel to the flow of arc current. Another embodiment utilizes a center insulator having an arm radially extending arm to the sidewall. Current flow through the melt to an electrode therein creates a magnetic field for precession of the arc. The arm prevents reversal of current flow in the melt to assure unidirectional arc precession. A split-ring electrode having an insulating ceramic insert can also be used in place of the center insulator and arm to produce precession.

Application of Composite Insulators to Transmission Lines Prepared by the Task Force Members of the IEEE Working Group on Nonceramic and Composite Insulators for Transmission Lines, Lightning and Insulator Subcommittee

Abstract: The paper provides guidelines for the application of composite insulators to transmission lines. These guidelines are based on utility field experiences, results of research laboratory tests and manufacturers' recommendations. Discussed are interchangeability with porcelain and glass insulators, application in contaminated environments, material ageing, insulator icing, the use of grease, resistance to vandalism, temperature extremes, and the need for grading rings. Clarification is provided on the mechanical rating of composite insulators because there is not yet general agreement by various industry groups.

Electrical resistance heating assembly

Abstract: An electrical resistance heating assembly having specially designed electrical insulators is disclosed. The electrical insulators have arms shaped to retain an electrical resistance heating coil which can be quickly, easily, and reliably mounted on the arms of the insulator. Top parts of the arms are generally rectangular or triangular in cross section and the arms are spaced and configured relative to each other to form a generally T-shaped opening between the arms, with the ends of the cross bar of the T-shaped opening forming electrically resistance heating coil retention surfaces. Also, cuts in side surfaces of the insulators may provide additional coil retention surfaces. The insulators have either an extended base portion for directly mounting the insulators to a mounting bar of the electrical resistance heating assembly or the insulators simply comprise slabs of electrically insulating material which are each mounted on a cross bar which is attached to a mounting bar of the electrical resistance heating assembly.

Hole current in dual dielectric under positive gate voltage

Abstract: n-channel dual-dielectric transistors with SiO 2 :Si 3 N 4 gate insulators were fabricated with and without boron implant in the channel. Under positive gate voltage stress, electrons can enter the insulator from the silicon, and holes can enter the silicon from the insulator. The electrons and holes were measured by the technique described by Ginovker et al.[1]. For oxides thicker than 30 A, it is always observed that the silicon hole current is 3-4 orders of magnitude below the silicon electron current. The physical origin of this hole current is shown to be field-enhanced excitation of electrons from the valence band to the conduction band in the silicon prior to entering the insulator, and is not due to the holes from the insulator entering the silicon.

Pulse Flashover of Solid Dielectrics in Vacuum

Abstract: In an effort to understand the mechanisms which lead to changes in the surface flashover potential of insulators used in high power spark gaps a systematic study of the flashover potential of various organic insulators was undertaken. The flashover potential of these insulators was measured both before and after they had been exposed to the by-products of an arc from a surface discharge ignitor plug. These insulators were analyzed using Electron Spectroscopy for Chemical Analysis (ESCA) to determine what, if any, structural changes occurred on the surface of the insulator as a result of the flashover events and/or irradiation. A Scanning Electron Microscope (SEM) was also used to investigate the tracks formed on the insulators as the result of a surface flashover.

Thin film electric field light-emitting device

Abstract: A thin film electric field light-emitting device has a thin fluorescent film, a thin dielectric film, and electrodes for applying a voltage to the films, the thin dielectric film is composed of a dielectric expressed by the general formula AB2O6, where A is a 2-valency metallic element and B a 5-valency metallic element. This dielectric is used to reduce the drive voltage without decreasing the intensity of the light emitted by the light-emitting device. Further, a composite laminate of thin dielectric films i n which thin dielectric films that do not break down a self-recovery type of insulator are used, thereby causing the entire composite thin dielectric film to break down the self-recovery type of insulator in such a manner that the value of the product of the insulating breakdown electric field intensity and the specific dielectric constant is large, thereby providing a thin film electric field light-emitting device with excellent characteristics.

Application of hydrogenated amorphous silicon in charge-coupled devices

Abstract: Theoretical and experimental studies in the application of a-Si:H to charge-coupled devices (CCDs) are summarized and recent results are presented. The device operates in a new mode where transient signal electrons are stored in the accumulation state of the a-Si:H/insulator interface. Taking multitrapping effects of electrons by localized states into account, charge transfer characteristics have been analyzed. It is shown that the clock frequency can be increased without degradation of the transfer efficiency by shortening the transit time of conduction electrons. The first a-Si:H CCD operation has been confirmed experimentally by an insulator/a-Si:H/insulator structure sandwiched between staggered transfer electrodes. Then, the improved device structure with resistively connected transfer electrodes has been developed. The device operated with the transfer efficiency of more than 99%/ transfer at clock frequencies between 1kHz and 200kHz.

Cast-resin insulator for high-voltage cable end closures

Abstract: A cast-resin insulator for high-voltage cable end closures, having an internal hole and a field-control funnel is intended to be capable of universal use, to control the field in an optimum manner, and to be of simple construction. This is achieved essentially in that the insulator (1) is considerably thicker in the lower half (2) than at the top and, at the bottom, has an expanded inner hole (4) into which an adapter (6) consisting of elastomeric insulating material is inserted, and in that, at the bottom, the insulator has an annular recess (5) which is constructed in accordance with a Borda profile and carries a conductive coating (7).

Electric field luminescent element

Abstract: PURPOSE:To provide the titled element that is suitable for a display device and excellent in luminance, and in which driving voltage therefor is low, by laminating, on one or both surfaces of an electric field luminescent layer, yttrium oxide layers and insulator layers with a high dielectric constant, and providing electric field applying means. CONSTITUTION:A transparent electrode 2 of indium oxide is formed on a glass substrate 1, and a first insulator layer 3 having a high dielectric constant and including as major constituents bismuth titanate, barium titanate, calcium titanate, etc. is formed thereon. Then a second insulator layer 4 consisting of yttrium oxide is formed thereon in a thickness of 0.01-0.1mum. Further, an electric field luminescent layer 5 consisting of zinc sulfide containing one of Mn, Cu, Ag, etc. is formed thereon. In addition, a third insulator layer 6 consisting of yttrium oxide in a thickness of 0.01-0.1mum, and a fourth insulator layer 7 having a high dielectric constant are successively formed thereon, and then reflective electrodes 8 are formed to obtain the intended electric field luminescent element.

Electric field arising from a heterocharge accumulation on the surface of a solid insulator in a vacuum

Abstract: The electric field arising from a heterocharge surface distribution present on a solid insulator is calculated as a function of insulator length at the solid insulator-vacuum interface, inside the solid insulator and in the vacuum. An enhancement in the field is observed at the cathode and anode junctions. The field enhancements at both electrode junctions age found to increase with increasing insulator length leading to the nonlinear dependence of the withstand voltage on insulator length.

High voltage spark electrode structure

Abstract: With the addition of a conductive means in the form of a grounded ring or member placed at the insulator means of a high voltage spark electrode structure, the required break down voltage of the spark gap can be reduced. The conductive means typically would be a ring encircling the insulator means of the electrode structure and would provide a ground as well as a mechanical support near the end of the insulator means of the electrode structure.