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The solid electrolytic capacitor structure (1) has been investigated for high purity aluminum utilizing both wire and porous anodes. The major problem with aluminum anodes is that a normal anodically formed aluminum oxide is extensively damaged during the high temperature decomposition (300-500°C) of aqueous solutions of manganese nitrate in the formation of manganese dioxide, the semiconductor cathode...
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A re-entrant resonant cavity was constructed for measuring the breakdown strength of dielectric samples at 630 mc/sec. The cavity was tunable by means of a choke plunger to accomodate various thicknesses and permittivities of dielectric. It was also pressure tight to allow pressurizing if necessary to avoid arcing or gas breakdown around the sample. This was an unnecessary precaution, however, since...
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The inherent high accuracy of the (1) liquid displacement test method for determining the dielectric constant of sheet insulating meterials is well established. However, there is a growing need to extend this method to a frequency range above the present maximum of 1 megacycle.
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There is considerable interest in the effects of corona and, in particular, as to whether it can be measured accurately and its effects likewise correlated. It is obvious that it would not be useful to determine a level resulting in damage to a sample and not be able to measure a corresponding level within apparatus.
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The object of this paper is to report recent measurements of the conductivity of polystyrene film under relatively high electric fields, and to describe a field effect on the conductivity of that material. Although the existence of a field effect on the conductivity of crystalline materials such as mica was reported by Poole (1), no such data has appeared for amorphous materials such as polystyrene.
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The subject of electrets and their theoretical justification is, at best, confused. First, to review briefly the history of the subject, the name “electret” was devised as an electrical analogue to “magnet”. As the name implies an electret is an object having associated with it an apparently permanent electric field. This must be clearly distinguished from a battery which can continuously supply current...
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Surface carbon tracking of insulating members in electrical equipment is a problem which is receiving increased attention from both suppliers and users of electrical components. The principle emphasis towards the solution of this problem has been placed on the development of track resistant insulating materials which are capable of being formed by various techniques into solid track resistant insulating...
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The behavior of particles in a combined gravitational and nonuniform electric field is used to produce separations of materials having different dielectric constants. This paper describes recent improvements to the apparatus previously used for the continuous separations of physical mixtures. The separatory operation consists of passing the finely divided material through a pair of diverging electrodes...
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Five years ago, the author presented to this Conference a paper entitled “A New Approach to the Analysis of Insulating Liquids”. In addition to presenting theories concerning the behavior of insulating oils, this paper described the Doble Oxidation Test which furnishes information during an accelerated life test that is indicative of the oil quality and its probable service performance by determining...
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Although the gassing of electrical oils under stress has been studied for many years and discussed by a number of authors (1–4, 6–8, 10,11), there appears to be no general agreement as to test methods nor even as to the influence of some of the major test variables. Recent work of Basseches and co-workers indicates that various free-radical reagents will greatly reduce the gassing of paraffinic oils...
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Ability to absorb hydrogen under electrical stress has long been considered an important property of cable oils, and various laboratory test techniques to measure this property have been developed (4,6,8,17,19,20). However, all these direct measurements of the tendency of an oil to evolve or absorb gas require complicated apparatus with high voltages. Such apparatus is suitable for referee and research...
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A trend towards miniaturization of equipment and accompanying higher operating temperatures exists in many phases of the electrical industry today. This trend, especially when coupled with the many military applications requiring a high degree of thermal stability, has indicated a need for new high-temperature insulation components. Such a need has been further crystallized by the inadequacies of...
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The behavior of an insulator when subjected to electrical discharges often determines whether it can be used in a particular electrical device. There are various tests available for evaluating the discharge resistance (arc resistance) of insulation but their results do not correlate very well with field behavior. A more reliable testing procedure is needed which also yields information on the breakdown...
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Dielectric spectroscopy has been used to elucidate the essential structure of carnauba, montan and ouricuri waxes. By analysis of the dielectric constant and loss curves as determined over a broad range of temperature and frequency, it has been possible to establish the presence of permanent electric moments in the molecules and to determine that association through hydrogen bonding exists. Polar...
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The significance of corona discharges in insulation structures has been recognized for many years. This paper presents a refinement of an old technique for measuring corona, together with an extended interpretation of the results which should have utility in both laboratory and shop measurements of insulation structures.
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The Standards Group within the Dielectrics Section of the National Bureau of Standards has undertaken an investigation with the object of producing a set of Standard Specimens with well-defined dielectric constant and loss index. An important attribute of such a group of specimens is that their electrical properties should not be subject to unpredictable change as a function of environment or time...
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Chemists have made contributions of two kinds to electrical insulation development. One is to the understanding of the relation between dielectric behavior and chemical structure, and the other, possibly less appreciated, to the development of ways of extending the service life of dielectrics.
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The aim of our research is to make a convenient and accurate resonant cavity dielectric measuring system for samples in the shape of a small rod or filament. The use of a circular TMOlO mode for rod samples is well known (1) but is not always so convenient because the sample changes the cavity frequency, which may necessitate re-matching of several parts of the system. This mode is, however, very...
