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While there are many factors that influence the discharge inception voltage, commonly known as corona start voltage (CSV), in gas-solid dielectric systems, only three or four will be brought out here. Some of these factors are not new, but will be presented somewhat differently in hopes that those who deal in the direct application of dielectrics to practical systems may find a little better tool...
The physical processes operative in the development of electrical breakdown in a dielectric are often reflected in the time interval between the application of a d.c. voltage and the appearance of the spark. This time may include both the time required for a free electron to appear near the cathode (statistical time lag) and the time required for the spark to develop after such an electron begins...
A broad-band spectral analysis was undertaken of the dielectric properties of ferrites (polarization, magnetization and conduction) from d.c. to the optical spectral region. After a short description of the various measurement techniques employed, characteristic data are given of electronic conduction, space-charge polarization, infrared absorption, and ferromagnetic resonance. Various additional...
The results of a study of the propagation mechanism of impulse creepage discharges over oil-immersed Kraft board is reported in this paper. This study was carried out using Leica and high-speed Boys cameras to record the progression of the discharges and using a special probe technique to measure the discharge potentials at various points along the channel. The electrode configuration used in these...
The purpose of this paper is to describe some effects of beta radiation on the conductivity σ of good insulators (i.e. σ< 10−17mho/cm) as a function of radiation rate, total irradiation time and temperature. The historical background will first be given; then, some recent measurements will be described and related to theory; and, finally, some practical applications will be discussed.
The intent of this paper is to point out the need for a careful analysis of some of the theories concerned with the life characteristics of liquid insulation of petroleum origin. Data pertaining directly to one type of liquid commonly known as transformer oil are used but the basic principles involved are not necessarily restricted to transformer oils.
Haworth and Bozorth, as well as von Hippel, many years ago observed that the prebreakdown current in dielectrics may be accompanied by characteristic noise phenomena of a not clearly established origino Lately, several scientists have ascribed this noise to impact ionization in the dielectric and deduced the number and height of these avalanches from it. This interpretation appears very doubtful,...
In 1949 a paper was presented before this Conference on Electrical Insulation giving the results of measurements of volume and surface conductivities made on Polystyrene, Polymethylmethacrylate and Polyvinylbutyral under standard room conditions. The use of a vibrating reed electrometer in place of a more sluggish quadrant electrometer has permitted a more detailed study of the current flow through...
A new method is described for determining the effect of thermal aging on the shearing modulus of flexible sheet insulations by non-destructive tests using a torsion pendulum technique. The test sample consists of a twelve-inch length of the material under test clamped between two pairs of inertia bars of different weight and inertia.
The increase in viscosity of a polar liquid which occurs when a constant electric field is applied across the capillary in which the liquid is flowing saturates at a high field intensity, and no further viscosity increase occurs (fig. 1(a)). This saturation effect has a long time-constant, and disappears if a very low frequency field of 1 c.p.s. is substituted for the D. C, field (fig. 1(b)); this...
General Electric Company has introduced a new type of silicone rubber coating compound SE 100 to the field of electrical insulation. This material and silicone rubber-glass cloth products made therefrom represent a significant advance in the industry. Through a study of the components parts of the coating formulation-polymer base, filler, and curing agent — and the rheological properties deemed necessary,...
Conference proceedings front matter may contain various advertisements, welcome messages, committee or program information, and other miscellaneous conference information. This may in some cases also include the cover art, table of contents, copyright statements, title-page or half title-pages, blank pages, venue maps or other general information relating to the conference that was part of the original...
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