Showing papers on "Insulator (electricity) published in 1973"

Mechanism of Surface Charging of High-Voltage Insulators in Vacuum

Abstract: In vacuum, the surface of insulators becomes electrically charged when subjected to high-voltage stresses. The charging mechanism is described. A model simulating the charging shows that the surface charge densities are proportional to the applied voltage and depend on the secondary electron emission of the dielectric surface. It is also time dependent. Surface charges are shown to explain many results obtained in studies of insulator surface breakdown.

Dynamoelectric machine stator assembly with multi-barrel connection insulator

Abstract: Single body of insulation for insulating one or more external lead wire connections in an area of end turn region having a paucity of end turns. Insulator may be used to anchor lead wires and may be fabricated of a sheet insulating material, for example by employing seam welding process. Insulator material defines a plurality of axially extending insulating compartments that receive external lead wires and winding tap wires. Each compartment is laterally separated from at least one adjacent compartment by at least one layer of insulating material. Insulator may comprise a plurality of independent tubular sleeves held together by a common exterior tubular sleeve. Insulator may include plurality of insulating compartments that are defined by a single or common sheet of insulating material.

Dielectric diode, fabrication thereof, and charge store memory therewith

Abstract: A dielectric diode is provided in accordance with the principles of this invention. The dielectric diode is in the form of a capacitor wherein one of the electrodes has a high contact barrier, e.g., 4 electron-volts, and the other has a low contact barrier, e.g., 1 electron-volt, giving the resulting structure a diode behavior. Illustratively, the electrode at the low contact barrier comprises a valve metal or a very reactive metal which has been anodized or oxidized to provide a layer region with a given concentration of positive ions. The resulting metal oxide is covered with a wide band gap insulator such as SiO 2 . The composite contact barrier from the conductor to the insulator is typically less than 1 eV and results from the transition layer region between the conductor electrode and the insulator layer. The wide gap insulator layer is covered on the opposite surface with another electrode which has a high contact barrier. Electronic current will tunnel easily from the first electrode into the insulator layer via the composite contact barrier and then will be collected by the second electrode as a relatively large tunnel current. However, the tunnel current from the second electrode, through the insulator and to the first electrode is relatively quite small at electric fields less than 10 6 volts/cm. A dielectric diode provided in accordance with the principles of this invention can be used to charge and discharge a capacitor, forming a memory cell. The charge on the memory capacitor can be sensed by a field effect transistor.

Post-Type Support Spacers for Compressed Gas-Insulated Cables

Abstract: The flashover performance of post-type support spacers for concentric compressed gas-insulated transmission lines was investigated. The experiments were made with SF6 gas at 4.4 atm. abs. and low frequency AC voltage in the EHV range. Nine cast epoxy spacers with metal inserts at each end shaped to produce different electric field distributions along the solid-gas interface were tested. The results show that flashover voltage is controlled by the electric field distribution and is inversely proportional to the stress enhancement in the gas. This conclusion is shown to be consistent with ionization-initiated breakdown at a certain stress limit about 300 kV/cm in these studies. The better designed spacers were limited by sparkover of the radial gas-gap at 1300 kV peak and not by surface flashover at the insulator.

Flat flexible transmission cable

Abstract: Improved flat flexible cable having at least one shielded transmission line is disclosed. The subject cable is formed with either a single or a plurality of signal conductors on one side of a flat flexible insulator substrate and one or a plurality of ground conductors on the opposite side of the substrate, the ground conductors preferably being interconnected. Pads are formed at periodically spaced intervals along each of the signal and ground conductors so that the cable can be produced with infinite length and cut to finite lengths at the pads nearest the desired length while maintaining constant electrical transmission properties (such as characteristic impedance, cross-talk, attenuation, etc.) throughout the length of the line and including the termination area.

Optimization of Insulators for Gas Insulated Systems

Abstract: The general problem of which insulator configuration is best for gas-insulated systems is considered. A smooth disc is compared with both a corrugated disc and a cone and the cone is seen to have considerable potential. Impulse and switching surge voltages are more severe than 60 Hz when contamination is present on the insulators. When insulators are contaminated, the dielectric strength cannot be increased by increasing pressure.

Non-volatile diode cross point memory array

Abstract: A dense memory array in which every cross point of two insulated orthogonal sets of lines define a non-volatile memory device is described. Each device utilizes voltage and storage charge to control breakdown characteristics of a PN junction. Basically, the array comprises insulated metallic word lines orthogonal to bit line diffusions in a semiconductor body. The insulation between the word lines and the bit lines has dual charge states and can store charges. Biasing of the word and bit lines causes charges to be injected into the insulation to affect the surface field of the body and thus change the breakdown voltage of the diffusion with respect to the semiconductor body. Both the read and write operations involve voltage breakdown of the PN junction between the diffused bit line and the body. During the write operation, an avalanche breakdown of the junction is caused to occur and charge carriers are injected into the overlying insulator. The charge carriers so injected remain localized in the insulator immediately above the junction and therefore do not disturb the information on adjacent bit lines. To erase, a voltage is applied to cause the injected carriers to be driven out of the insulation into the substrate. Reading consists of sensing the breakdown voltage of the selected bit.

Ignition plug with auxiliary electrode

Abstract: An ignition plug having a center electrode, an insulator surrounding the center electrode, and a metal plug surrounding the insulator and having a ground electrode and opposing the center electrode; further, the plug comprises an auxiliary ground electrode provided with an anti-fouling gap against the insulator surrounding the center electrode at the tip end of the metal plug.

Insulator assembly having load distribution support

Abstract: A ceramic insulator assembly includes a plurality of parallel vertical insulators arranged with equal spacings about the circumference of a circle. Vertical loading forces are applied to the insulators by way of an adapter plate separated from a top plate on the insulators by a load distribution ring. The ring is aligned with the axes of the insulators, so that bending forces are not transferred to the insulators. A plurality of vertical tiers of insulators separated by divider plates may be provided. One end of each insulator may be mounted in a molded joint to insure substantially equal load distribution.

Over voltage arrester

Abstract: An over voltage arrester is formed with electrodes inserted into the ends of a tubular insulator member and assembled in gas-tight relationship by glazing the electrodes to the insulator member, at least one of the electrodes being in direct electrical contact with a conductive triggering strip supported on the tubular insulator member, such triggering strip being in direct contact with the electrode in the area of the glazed connection between the electrode and the insulator member.

High voltage circuit interrupter switch arrangement

Abstract: A high voltage circuit interrupter is enclosed within an integrally formed insulating housing that includes the operating mechanism enclosure, the insulator portion, and the muffler portion. The integrally molded insulating housing increases the interrupting capability of the interrupter. Also provided at one end of the housing is an alumina particle muffler for absorbing hot arc gases produced when the switch opens or closes. A trailer is connected to the moving contacts of the switch and the trailer is formed of a material that produces an arc quenching gas when exposed to an electrical arc. A very small vent hole is provided through the housing adjacent the muffler to provide controlled venting to the atmosphere so that the gases are essentially confined within a suitably large volume of the housing to increase the dielectric strength. External and internal surface coatings may also be employed to provide voltage grading and to eliminate corona and RIV noise.

Charge storage characteristics of MIS structures employing dual‐insulator composites of HfO2–SiO2 and SrTiO3–SiO2

Abstract: Two MIS versions have been fabricated employing rf‐sputtered dual insulator structures comprised of 1000 A HfO2‐20 A SiO2 and 1000 A SrTiO3‐20 A SiO2. The high‐dielectric‐constant insulators in combination with a 20‐A layer of silicon dioxide permit the transfer of charge by tunneling into traps at the dual‐insulator interface to occur at considerably lower voltages than comparable structures employing silicon nitride or aluminum oxide. It was found that trap density and, hence, the degree of flat‐band voltage shift could be altered by sputtering 50‐A layers of selected materials at the insulator‐SiO2 interface. The devices employing hafnium dioxide show promise in an application as a nonvolatile electrically alterable memory element. Although the strontium titanate devices exhibit a low threshold voltage for onset of charge transfer, the charge retention characteristics are poor.

Self-recovering current limiter

Abstract: A self-recovering current limiter of the character wherein a circuit breaking condition is provided by vaporizing a current limiting material when a short circuiting or fault current occurs, and being self-restorative to a conductive condition by liquefying the current limiting material after the passage of a specific period of time. Essentially, the self-recovering current limiter comprises a heat resistant and alkali-metal resistant insulator made of beryllia porcelain, alumina porcelain or the like having a channel holding a self-recovering current limiting material which has high impedance in its vapor condition and high conductivity in an orginal liquid condition, an outer tube made of stainless steel or brass surrounding the insulator, and an insulating material packed between the outer tube and the insulator at a temperature higher than that at which it becomes softened.

Amnesia in layered insulator FET memory devices

Abstract: A retention time theory is developed for layered insulator FET (LIFET) memory devices in which the dominant cause of amnesia is attributed to tunnelling of charge back to the silicon. The theory incorporates the effect of surface states and the time dependence of the electric fields in the insulators. An equation for the threshold voltage correct to first order in the electric field is derived and solved exactly. To facilitate comparison with other theories, the solution is given in expressions valid over several decades of time. The solution predicts in agreement with experimental results that after a delay time which is exponentially dependent on the initial threshold voltage, the oxide thickness and the surface state density, the threshold voltage decays logarithmically eventually tailing off exponentially. In the logarithmic regime the decay rate varies as the inverse square of the oxide thickness, the square root of the trap depth and inversely as the rate at which the density of surface states increases. The calculated decay rate is found consistently to be lower for alumina devices than for nitride devices. The effect on the decay rate of trap depth, density of surface states, thickness of each of the two insulators, the dielectric constant of the thicker insulator and the initial threshold voltage are carefully examined and the results presented in the form of graphs and tables to provide guidance for memory product design.

A Study on Dynamic Voltage Distribution on Contaminated Insulator Surface

Abstract: Dynamic voltage distribution on an insulator unit was investigated before and during scintillation activity. A simple method for the measurements of voltage distribution was successfully developed. It was observed that some parts of the leakage distance do not function during scintillations, and therefore the concept of "effective leakage distance" was introduced. A good correlationship between " effective leakage distance" and flashover voltage was found.

Supplemental insulation with bypass impedance for electrical lines

Abstract: This invention relates to insulator assemblies for electrical lines, which are provided with supplemental insulation covering the pins, caps, support or suspension fittings of these assemblies as well as parts of their support and suspension structures and of the conductors. In order to uniformize the voltage distribution over the insulators each cap is covered with an electrode connected through impedances to the electrodes on the neighboring insulator caps. The supplemental insulation may consist of silicone grease, insulating tape, or glass. The bypass impedance may consist of resistive, inductive or capacitive elements.

Gas filled electrical bushing with concentric intermediate electrodes

Abstract: A bushing is disclosed which comprises an insulator including a plurality of stacked insulator units, a plurality of splicers for hermetically connecting the insulator units to each other, SF6 gas introduced into the insulator, a central conductor disposed at the center of the insulator to form a current path and at least a cylindrical intermediate electrode concentric with the central conductor and electrically connected to the splicers. Provision of the intermediate electrode causes divisions of the electric potential of the central conductor to be applied to the splicers, thus enabling proper control of the potential on the surface of the insulator.

Vacuum Insulation for Cryocables and Its Resistance to Discharges

Abstract: A test length of a liquid nitrogen-cooled, vacuum-insulated coaxial cable for use in underground power transmission has been studied with respect to its high voltage insulation properties. The critical element in the cable is the spacer between the conductors, since electrical discharges in the system are easily initiated across this spacer. Previous experiments with voltage sources capable of supplying low currents indicated insignificant discharge damage to the spacer as long as inorganic materials were used. The new results given in this paper show that insulator damage may still be small for discharges with peak current amplitudes up to 40 kA. The discharge current was supplied by an energy storage capacitor bank for a large number of tests with the same spacer. In addition to current measurements, photographic records of the discharges are presented and an assessment of the damage to the insulator and conductors is given.

Optical conducting fibre tape - comprising glass fibres welded between plastics insulating strip

Abstract: Optical conducting fibres are stretched out in a straight line and sealed between insulating pref. transparent strips of plastics material by welding the plastic along the sides of each fibre. Several fibres can be welded into the same strip, running parallel and spaced from each other in the form of a tape. the preferred plastic insulator is polyethylene.

Electronic relaxer and stabilizer

Abstract: An apparatus using an electric shock to relax and stabilize poultry as they move along a defined path in a poultry processing plant. The apparatus includes a frame structure with electrodes mounted thereon in spaced apart relation and has an electric power supply connected to the electrodes to apply an electric potential difference therebetween. Conveying means carry the poultry, that are to be processed, through the apparatus wherein the poultry engages the electrodes and forms a conductive path therebetween so that an electric current from the power supply passes through the poultry to shock and relax them. Non-conductor shields and insulator structure prevent current from passing through the conveyor and protects persons from contact with conductors.

Electric resistance heating element

Abstract: A resistance heating assembly in which the heating element is a thin strip of apertured, foil-like material formed with a series of corrugations which establish a wavy or serpentine pattern. The heating element is supported by tubular insulators carried by a wire framework and located at the points of direction reversal of the serpentine pattern. The insulators are supported on wire members each having one end secured to the wire framework and a free end extending into a tubular insulator. The tubular insulators are secured against axial movement on the wire members but are rotatable relative thereto, whereby localized expansion and contraction of the strip is distributed over the entire length of the strip.

Process for manufacturing a conductive film for a thin film integrated circuit device

Abstract: A low specific resistive conductive thin film for a thin film integrated circuit includes a high conductivity metal film formed on an insulating base plate. An insulator film is formed over that metal film. A metal succeptible to being anodically oxidized is formed over the insulator film and penetrates through fine pores in the insulator film to make electrical contact with the first-mentioned metal film.

Electrical temperature sensor - esp for measurement of temperatures of exhaust gases in vehicles

Abstract: The electrical temperature sensor, especially for measurement of exhaust temperature in vehicles comprises a resistance element whose resistance varies with temperature. The element lies at the base of a boring in the metal housing and has its top side connected to a metallic electricity conductor which fits into an insulator which isolates the conductor from the housing electrically and thermally, the conductor presses the resistance element against the base with aid of current carrying spring whose pressure can be adjusted by a pin. The insulator has one shoulder against which rests the soft metal washer to hold the insulator tight in the housing, there is also a flat spring washer between the insulator and the housing ledge.

Reversal developing method using photoconductive developing electrode

Abstract: A developing technique and apparatus is provided wherein an insulator having thereon an electrostatic latent image is positioned across a gap from an electric field controlling insulator. The gap is provided with developing particles, charged with the same polarity as the electrostatic latent image. The electric field controlling insulator is designed to have a surface potential characteristic similar to the insulator upon which the electrostatic latent image is formed, and is charged to the same level and with the same polarity as the image. As a result, the electric field controlling insulator will have a field variation compensation effect relative to the electric potential otherwise generated by the electric field controlling insulator.

Two‐carrier model for high field conduction in SiO2

Abstract: The current mean field strength characteristics are calculated for a special model of an insulator in which low‐mobility holes are thermionically emitted from the anode and high‐mobility electrons are cold emitted from the cathode. In the general case, the conduction characteristics are both thickness and temperature dependent.

High voltage in-line disconnect switch

Abstract: A switch is provided for insertion directly into a high voltage power line to provide means for electrically disconnecting an extension of the line The switch employs an insulator having high tensile strength and a high dielectric constant which can physically support a power line and also withstand the electrical forces applied through the line The electrical circuits are either completed or broken through action of a switch blade which can conduct electric current between hardware components connected to end fittings on the insulator The end fittings are tapered and faced by steps to prevent their being pulled from the hardware or rotated with respect to the hardware

Leakage surge indicator

Abstract: An indicator to indicate or count or record the leakage surge across an insulator of a high voltage transmission line.