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In this paper the results of an experimental study concerning the vegetable oil's (subjected to thermal ageing) lifetime estimation based on the activation energy and IEC 60216-1/2001 methods are presented. Three accelerated thermal ageing tests were performed on transformer vegetable oil samples at 135, 155 and 175 °C. The lifetime curves were drawn for three diagnostic factors, namely loss factor,...
A rapid method, based on a logarithmic degradation model of insulation material, is proposed to reduce the test duration in lifetime assessment of cellulose paper insulating materials. This method proposes the determination of the activation energy from a non-isothermal measurement made by differential scanning calorimetry or another thermal analysis technique and an aging test at a single elevated...
Lifetime estimation of mineral oil is based on IEC 60216-1/2001, using accelerated thermal ageing at three temperatures), method which requires a long experimental time. In order to reduce the experimental times, this paper proposes a simpler method to draw the lifetime curve by determining an experimental point (carrying out only a thermal ageing at the highest temperature - which requires the least...
Electrical machines' composite insulations conditions can be characterized by the values of the dielectric properties. In this paper, an experimental study of the variation of these properties with temperature and applied electric field frequency are presented. The tests were done on plane samples and bars containing CALMICAGLAS, made of glass texture (13 %), mica paper (47 %) and epoxy resins (40...
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