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In the manufacture of electrical and electronic packages and assemblies, conformal coatings are employed to protect the electronic package from moisture, gases, and other constituents of harsh atmospheres. In addition, circuit board dielectric characteristics can be improved by proper use of conformal coatings. The actual product use and design requirements will normally dictate the method of coating...
A new test facility has been built to assess the effect of long-term cyclic duty on generator armature insulation systems. In this facility it is possible to isothermally age or thermally cycle armature insulation systems in simulation of base-load or cycling service conditions. Results obtained from a three-year aging program on two service-proven base-load insulation systems are presented.
Federal and state air pollution control regulations will increasingly influence the electrical and electronics industry during coming years. During the past decade, most regulations have focused on major combustion sources (e.g., electric utilities and other major fuel consuming industries) and the large scale processing industries (e.g., petroleum, chemical processing, paper, primary metal production)...
Recent events at EPA and growing problems throughout the United States with waste disposal sites have had a negative effect on the public's perception of waste disposal and are resulting in growing Congressional pressure to upgrade regulations in the waste area and provide more protection for victims of hazardous waste problems. Members of both the House of Representatives and the Senate have indicated...
Three prominent biaxially oriented capacitor films were investigated for surface defects and thickness variation. Breakdown voltages of the film were determined and explained in terms of probable causes. An inverse relationship of breakdown voltage and dielectric constant was found.
For years, measuring the dissipation factor tip-up has been a recognized criterion for stator coil insulation acceptance testing and evaluation. Additional information on the insulation quality can be gained using hf-methods to determine and indicate voids in the insulation. Investigations showed that weak spots hidden in the cumulative measurement of the power factor tip-up are found by selecting...
Satisfactory service life under specified service conditions is the main criterion for evaluation and classification of insulating material and insulation systems. The ultimate proof of service life is provided on the basis of service experience. This is reflected by existing standards, guides and recommendations which use or claim for (service-) experience and accepted tests as a basis for evaluation...
Two new applications have been developed for use of adhesive systems in electronic assembly. The first application deals with the use of an advanced material to provide mechanical mounting to an output choke assembly while meeting the ferrite cores electromagnetic requirements. The second application provides electrical insulation, necessary mechanical bonding and thermal conduction path from power...
Electrically-conductive organic compounds have an unusual combination of properties which may make them suitable for microelectronic devices. Generally, the materials have low conductivities initially, but reaction with suitable oxidizing or reducing "dopants" causes dramatic changes in electrical, optical and magnetic properties. These materials offer a unique opportunity to modify properties...
Corona is initiated in high-stress regions and thus it can be suppressed by applying a semiconductor coating on the surface to relieve localized high stresses in those regions. Our investigation shows that silicon carbide has an excellent non-linear current field (I-E) characteristic and it is therefore a very good semiconductor-coating material for effective corona suppression. Theoretical analysis...
At first, we have had long term evaluation of self-bonding magnet wire (SBW5) related to R-22 refrigerant resistant properties for hermetic field since 1981 E/EIC. Secondly, we also have tried the reliability evaluation tests of hermetic motor system applied with SBW5. From these results, we could get a conclusion that reliability of our SBW5 and the hermetic motor system is more excellent than conventional...
A significant recent development in conductor insulation is the electrostatic powder coating of copper and aluminum rectangular cross section wire for use in liquid filled transformers. DuraBIL∗ turn insulation is a single layer of epoxy povrier deposited electrostatically on conductors, then baked and cured, linking polymers to form a continuous coating. Bonded tightly to the conductor, the coating...
An essential step in any high-voltage design project is comprehensive testing to assure reliable performance of the component in field operation. When failures subsequently occur, reevaluation is required to identify the failure mechanism and determine why the original tests failed to discover it. This paper describes such a diagnostic procedure on a high-voltage integrated transformer designed for...
Nuclear environmental equipment qualification is used to insure equipment operability at an end of life condition following a design basis event. The environmental effects must be accounted for when making this determination. One aspect of the design basis event is chemical spray which is applied to mitigate the accident. The corrosive effects of typical containment sprays upon insulation systems...
Epoxy resin systems are being used to encapsulate various switchgear transformers for indoor and outdoor applications. However, some manufacturers are experiencing stress cracking problems associated with this resin chemistry. For this reason, urethane electrical resin systems have been developed and marketed as an alternative because of their excellent thermal shock, flexibility, and stress relief...
Substitution of magnetic ions in some semiconducting alloys produces materials with interesting properties having high potential for device applications. On the other hand, substitution of specific ions in magnetic materials produces p- or n-type semiconducting properties. In this paper we consider the effects of magnetic ion substitution in the zinc blende structured Hg1−xMnx Te and Cd1−xMnx Te on...
The voltage distribution over the surface of an insulator in humid conditions is determined by the shape of the insulator and the surface resistivity. The latter changes very rapidly with the temperature rise caused by the Joulean heating in the surface layer. In the paper a comparison is made between computed and observed temperature distributions on a cylindrical and on a disc shaped glass insulator...
The world-wide electronics market approached approximately $150 billion in 1982. Leading the advances are the computer, communication, and instrument products. In addition, there is a huge market for electrical conductors, components, and wire and cable. The producers of the products, and indeed many more, are all concerned with the characterization, reliability and quality control of the many diverse...
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