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A 50-ns pulse generator is used to obtain time-correlated current-voltage relationships in the prebreakdown region for a long vacuum gap with cold planar electrodes. Analysis of data indicates several sequential stages occur. These stages include an initial quiet stage of voltage increase without interelectrode current, a microdischarge stage, a field emission stage, a space-charge controlled stage, and a final low-impedance stage where the current becomes sustaining. Electrical breakdown of the gap is considered in terms of a positive ion front moving from the anode.

This paper shows how the well proved self-contained oil-filled paper insulated cable, with the technological improvements continuously introduced in the recent years, and with the use of intensive forced cooling can provide a reliable means for the transmission of several GVA at the highest voltages now being considered (750-1200 kV).

An analysis has been made to examine the effect of a constant applied electrolysing voltage on the performance of an isothermal batch electrochemical reactor in which the rate of the cathodic reaction is limited by mass transfer of a reactant to the electrode surface, a simultaneous secondary reaction occurring at higher cathode potentials. Numerical solutions are presented for a hypothetical process study to show how average production rates for various percentage conversions of reactant are influenced by the magnitude of the electrolysing voltage and the corresponding electrical energy requirement. The most noticeable effect is that the electrical energy requirements for a given production rate are very strongly influenced by both the degree of conversion of reactant and by the extent to which the secondary reaction occurs.

Low-voltage triode sputtering is a film deposition process capable of high deposition rates (100–600 A/min) using voltages less than 500 V and Ar pressures of about 1 μ. This paper considers the geometric aspects of low-voltage triode deposition which include: (1) the thickness uniformity over the substrate table; (2) step coverage; and (3) the geometric conditions that give the best thickness uniformity, step coverage, and maximum utilization of target area.

In-space electric heating systems, such as baseboard, ceiling cable, wall fan, and radiant panel heaters, are customarily controlled by line-voltage or low-voltage thermostats. Tests show that the overall performance of such a heating system is significantly affected by the choice of thermostat used. Recent tests have shown that solid-state controls applied to such heaters can provide improved heating system performance. This paper presents performance test data whereby the performance characteristics of the various heating systems may be compared.

The bias dependence of the nonlinear mixing characteristics of metal‐barrier‐metal junction currents is deduced assuming an electron tunneling model. The difference‐frequency beat voltage at frequency ω1−nω2, where n is an integer and ω1 and ω2 are the assumed frequencies of two induced currents, is found to have n zeros as the diode bias is varied. Recent experimental observations have demonstrated such characteristics.

Summary The results of studies on the effect of mechanical vibrations, generated by an external voltage, on the internal impedance of electrocapillary transducers are presented. The experimental results are discussed in terms of the electric equivalent circuit of electrocapillary elements. It has been demonstrated that the effect of mechanical vibrations on the internal impedance may be completely eliminated by a suitable connection of the electrocapillary element (Fig.4). It has been suggested that the results of studies of this kind may prove useful in the studies of varius electrochemical systems along with their significance for the theory and applications of the electrocapillary elements.

The switching behaviour of a Co3O4 coplanar switching device is studied. A description of the preparation of the Co3O4 thin films is given. The results of the experimental measurements are discussed and numerical calculations of the temperature behaviour, the time dependence of the current, the voltage, and the input power have been performed under the condition that the decomposition temperature of the Co3O4 material is not reached. The results are representative for substances with thermistor behaviour and for values of the current carrier activation energy ΔE ≈ 0.1 eV. Das Schaltverhalten von koplanaren Co3O4-Schaltelementen wird untersucht und eine Beschreibung des Herstellungsverfahrens der Co3O4-Schichten gegeben. Die Ergebnisse der experimentellen Messungen und die numerischen Berechnungen uber das Temperaturverhalten, das Zeitverhalten von Strom, Spannung und Leistung in Co3O4-Schaltelementen werden unter der Bedingung diskutiert, das die Zersetzungstemperatur von Co3O4 nicht erreicht wird. Die Resultate sind fur Substanzen mit Thermistorverhalten reprasentativ, die eine Ladungstrageraktivierungsenergie von ΔE ≈ 0,1 eV haben.

This paper describes some of the unique features of the Munich MP tandem facility. The improved voltage stabilizing system using the liner-terminal capacity and a time-of-flight system for absolute calibration and monitoring of the tandem beam energy with an absolute accuracy of 1.5 × 10 −5 are discussed. Results of their performances are presented. The improved voltage stabilizing system has been tested by means of the time-of-flight system. The residual ripple at the terminal was measured to be less than 260 V fwhm. The time-of-flight system allowed the establishment of an accurate calibration energy in the tandem range by measuring the first T = 3 2 resonance in 12 C(p,p) 12 C to be (14230.75±0.2) keV. The Munich MP tandem conversion and upgrading program, initiated in 1973, is discussed in some detail. It includes installation of NEC-components into our HVEC MP tandem accelerator. Finally we present plans to add a small energy booster to our MP tandem in order to increase the energy of the heavy ion beams presently available in our laboratory. It is designed to allow, typically, post-acceleration of Ni-ions from about 100 MeV to 200 MeV.

A distributed RC circuit model is used to describe an interdigital electrode transducer (IDT) having finite conduction in the electrode stripes. The distributed circuit is described by a set of differential equations whose solutions yield the current and voltage distributions along the aperture of the IDT. It is found that the electrode resistance causes a distortion of the excited wave amplitude and phase due to the nonuniform voltage and current distribution. An equivalent circuit for the terminal properties is also derived which illustrates the effects of conduction loss. The theory is also used to predict electrode efficiency, effective aperture weighting, and phase shift in weighted arrays.

SUMMARY This paper deals with the theory of asynchronous motors running at variable frequency. Motor characteristics are found by the help of a computer programme where higher harmonics are neglected, but the influence of saturation is considered. It is shown that it is impossible to get optimum performance if the voltage is a function of the frequency only. A regulator which controls the voltage as a function of both frequency and load to keep constant flux gives torque and current characteristics equal to those of a dc-machine. This paper presents two alternatives for such a regulator. Braking methods are discussed and a regulator principle for a four-quadrant drive without current sensing is shown.

Development of a new porcelain suspension insulator with a semiconductive glaze and improved shape is described. The development was carried out jointly by Ontario Hydro and Canadian Porcelain Company. These new insulators provide considerably improved performance under wet and contaminated conditions and thus allow the reduction of insulator string lengths, facilitating conversion of existing 115 kV lines to 230 kV operation, and development of compact high-voltage transmission line designs.

Our industry produces a large number of precision wire-wound resistors, for instance, types MVSG, $5-5, $525, S5-42, etc. With a tolerance for deviations from their nominal values of 6 = i(0.03-0.1)%. The instruments most suitable with respect to precision and efficiency for testing these resistors consist of class 0.02 type R337 and class 0.005 type ShCh-30 digital ohmmeters in conjunction with resistance boxes types R32q and R326 (with corrections). However, these bridges are expensive, in short supply, and require highly-trained personnel for their testing and repai~. The measurement error of these ohmmeters is determined virtually by the precision class of the reference resistance box. By selecting appropriately the ratio-arm resistances of the dc bridges shown in Fig. 1 and employing the suggested method for choosing its supply voltage, it is possible to assemble from the components mass produced by our industry a comparison bridge for testing resistances in the range of 0.1-100 ka with an error not exceeding 0.015%. The bridge ratio-arm resistances R 1 and R z consist of resistors typeR331 with nominal values of either 1000 (for the measurement range of 0.1-10 k~) or 10000 ~ (range of 1-100 k~). The actual values of the resistors should not differ by more than ~: 0.001% with their temperature coefficients of resistance being close to each other. The resistors are selected by means of their certified records obtained in state testing. Such a selection from 25-30 available resistors with the above nominal values does not present any difficulties. The resistance R consists of the class 0.01 resistance box type R327. In measuring on this bridge the resistor Rx made with a tolerance of ~0.05% is balanced with adecade resistance box by setting it to the nominal value Rxn of the resistor. Owing to the difference between Rx and Rxn , the bridge will be slightly unbalanced. It is known [1] that the unbalanced voltage in this case (when the above-mentioned requirements with respect to the precision of R, R 1, and R 2 are met) can be determined with sufficient precision from the expression

The Dommel-Tinney approach to the calculation of optimal power-system load flows has proved to be very powerful and general. This paper extends the problem formulation and solution scheme by incorporating exact outage-contingency constraints into the method, to give an optimal steady-state-secure system operating point. The controllable system quantities in the base-case problem (e.g. generated MW, controlled voltage magnitudes, transformer taps) are optimised within their limits according to some defined objective, so that no limit-violations on other quantities (e. g. generator MVAR and current loadings, transmission-circuit loadings, load-bus voltage magnitudes, angular displacements) occur in either the base-case or contingency-case system operating conditions.

We report the observation of voltage steps in the current-induced resistive state in superconducting strips of lead and indium. The strips were 1.7-6 mm long, 0.1-8.0 \ensuremath{\mu}m thick, and 100-300 \ensuremath{\mu}m wide. The voltage steps are attributed to the nucleation of trains of flux tubes moving rapidly from the edge to the center of the strip. In the center, opposite tubes arriving from opposite edges annihilate each other. The moving flux-tube trains are, obviously, the outgrowth to the case of a three-dimensional type-I superconductor of the dynamic behavior of the weak-link Josephson junction, and, in particular, of the Anderson-Dayem bridge. From a simple eddy-current-damping model we have estimated the number of flux tubes existing simultaneously in a single flux-tube train.

Reports an investigation into the use of a cheap electrolytic spirit level (vial) to detect change of building tilt due to soil subsidence (a few milliradians in a temperature environment of at least -5 to 30 degrees C). Vials of this type were found to have a wide spread in tilt sensitivity (for example +or-25%) and a significant tilt temperature coefficient ( beta ) of about -1% degrees C-1. An open loop tilt monitor requiring calibration with each vial is described; readings can be taken quickly, it has linearity of about +or-2% and employs an oscillator with negative source resistance to reduce beta to -0.1% degrees C-1. In a novel closed loop tilt monitor a vial is mounted on a piezoelectric bimorph and the voltage applied to the bimorph (being the output) is adjusted automatically to bring the vial to a horizontal position; linearity is about +or-0.5%, beta has a value of -0.1% degrees C-1 (without a special oscillator), but the system takes as much as 10 min to settle after large disturbance of the sensing head, which makes it unsuitable for the particular application. Both experimental monitors experience tilt offset of about -10 mu rad degrees C-1.

This paper studies the statistical performances of multi-break circuit-breakers. For the thermal reignition regime, a formal proof is given of the fact that under certain conditions (explicitly derived) the overall performance of a multi-break breaker is better than that expected from a proportional extrapolation of the results from a single break. For the dielectric regime, it is shown that the hitherto published formulas are conservative in the sense that they overestimate failure probabilities. Using these formulas, graphs are given which compare the failure probabilities of a four-break breaker in the dielectric regime with that of a single break under certain given fractions of the stress on the complete pole. Some general results of a statistical nature relating complete circuit breaker failure probabilities in the dielectric regime to a single break failure probability are also given.

An analytical model for trapping state photodepopulation measurements in conductor-thin film insulator-conductor structures is presented. The external circuit current dependence on applied voltage is determined, and it is shown that moments of the spatial distribution of trapped charge in the insulator can be extracted from collected charge vs. applied field characteristic curves. The photodepopulation technique is compared with more widely used differential capacitance and photoemission current techniques.

The classical two-axis model of the synchronous machine governed by Park's equations is expanded by' viewing the magnetic-field couplings along each axis as multiports characterized by typical matrices whose elements are pertinent open-circuit, short-circuit, hybrid parameters and system functions associated with specific port constraints. Four equivalent state models are presented. A hybrid dynamical model that uses the "constants" of the machine and represents rotor currents and fluxes by equivalent voltages is developed in the forms of state equations and analog computer representations as well as phasor diagrams based upon ignoring armature dynamics.

If a 0.001 in (0.025 mm) thick foil of polyethylene teraphthalate is metallized upon one side and a dc voltage is applied to the metallizing, then the foil will adhere firmly by electrostatic attraction to any conducting surface. In acoustic emission experiments with such a foil as a capacitance detector it was observed that by cycling the polarizing voltage it was possible to increase the sensitivity of the device until it was only 30 dB below that of a damped pzt transducer. Such an enhanced response probe has been found to have a frequency response which is flat from 10 kHz to 5 MHz. It also has the advantages of being lightweight; needs no coupling agent when applied to conducting substrates; is stable over long periods; can be made in any shape or array of shapes and will conform to curved surfaces

A basic design using time division multiplexing principles is reported for telemetering some measurements in a remote water-pumping station. A total number of twelve channels is provided and the bandwidth per channel is 300 Hz working from dc upwards. The discussion is emphasized on simple but adequate design techniques using inexpensive components. For the sake of clarity, only unconventional circuits used for multiplexing and de-multiplexing are described in detail, other more well-known building blocks being referred to the literature. The system has undergone extensive tests in the laboratory and its general performance is satisfactory and not affected by considerable fluctuation in sampling rate or power supply voltage. The de-multiplexing receiver also has the special characteristic that it can be made to scan continuously over every time-slot to select any channel in the system as desired, providing a time-domain equivalent to continuous tuning in the frequency-domain, a property particularly useful for testing TDM sources.

Digital computation of harmonic components of output voltage of multiphase controlled rectifier circuits is discussed. Harmonic components are calculated by using Fourier transforms. Computed results for a three-pulse controlled rectifier circuit with an R-L load are presented.

The transmission of monochromatic light through the sandwich cell of MBBA (a typical n-type liquid crystal) with vertical alignment is investigated. When the cell is set in crossed Nicol and controlled by a.c. voltages, the transmissivity is zero at any voltage V below the threshold value Vth. When V>Vth, it shows nearly a sinusoidal variation with V. This phenomenon is observed even with fairly thick cells (50 µm). The threshold voltage Vth is shown to be independent of the cell's thickness and about 4.0 V (r.m.s.) at 24.0°C for f

The capacitance vs voltage curve of thin oxide (30–40 A) MOS structures in strong accumulation was studied. The results were interpreted in terms of equivalent surface density of state masses, which was found to be 0·2 m 0 for the silicon valence band and 0·06 m 0 for the conduction band, for both 111 and 100 surfaces. The experimental density of state masses were shown to be much lower than the bulk values. Equivalent density of states masses were calculated from a surface quantization model and in this case agreement with the experiments was obtained for the valence band only.

This paper summarizes practical problems associated with electromagnetic currents induced by high voltage transmission lines. It deals with the safeguards necessary to counteract these currents and develops a method of calculation of electromagnetically induced voltages and currents.

The simultaneous correction of third order aperture aberration and axial chromatic aberration is studied theoretically to determine practical upper limits of the accelerating voltage. Aberrations of a round objective lens are compensated by a quadrupole-octopole corrector similar in design to the Archard, Deltrap and Hardy systems. Severe tolerances on lens stability, large electrostatic fields in the quadrupoles, and chromatic aberration of magnification are the primary factors that adversely affect the performance of these systems at high voltage. The variational calculus is used to compute correctors with low electrostatic fields in the quad­rupoles. When lens stability requirements are also considered, the general configuration of high performance systems is deduced. In addition to internal corrector structure, five parameters including voltage and magnification are used to define a system. Optical and field properties are calculated for a wide variety of these parameters. It is concluded that chromatic correction is feasible for accelerating voltages up to 500 kV. Lens stability requirements become very severe for beam energies greater than the electron rest energy, 511 keV. Tabular results are given for systems designed for resolutions of 1, 0.5 and 0.1 nm. In these examples lens stability requirements are one part in 5 x 105, 106and 5 x 106re­spectively. Configuration changes and their effects on stability and field of view are discussed.

Results of the experimental study of Au n-type SiC Schottky barrier diodes at room temperature are presented. The diodes are fabricated by vacuum-evaporating gold on chemically etched n-type hexagonal (6H) SiC surfaces and exhibit excellent forward current vs voltage characteristics with the exponential factor n of about 1·07±0·02 for voltages between 0·35 and 0·85 V. The linear part of the characteristic, in a semi-logarithmic plot, extends over seven orders of magnitude in current. The forward current-voltage characteristics are found to agree quantitatively with the theory based on thermionic emission with the barrier height modified by image force lowering. The Schottky barrier height is determined from three independent techniques: differential capacitance vs voltage, photoresponse, and forward current vs voltage methods. The barrier height deduced from the three methods is about 1·40±0·05 V.

Measurements have been made of the transient current response of InP samples following the application of a voltage step during the transit of a dipole domain through the sample. From these measurements values of the domain charge and differential capacitance have been derived as functions of the domain potential. The relationship between domain charge and voltage in InP is found to be different from that suggested by simple domain theory and found experimentally in GaAs of comparable carrier density. An approximate form for the electron velocity-electric field characteristic of InP is derived from the experimental data and evidence is presented to suggest that this represents an upper limit to the true characteristic.

As a result of full scale indoor operational ice tests performed in the Spring of 1973, it became apparent that high voltage air disconnecting switches built and tested under current ANSI standards will not perform satisfactorily when coated with 3/4 (1.9 cm) inch of ice and operated with a motor mechanism. It was also demonstrated that one motor operation both opening and closing under iced conditions is a piactical requirement and is within the design capabilities of most switch manufacturers.