Life Estimation of Electrothermally Stressed Epoxy Nanocomposites

Preetha, P and Thomas, Joy M (2014) Life Estimation of Electrothermally Stressed Epoxy Nanocomposites. In: IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION, 21 (3). pp. 1154-1160.

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Abstract

Accelerated electrothermal aging tests were conducted at a constant temperature of 60 degrees C and at different stress levels of 6 kV/mm, 7 kV/mm and 8 kV/mm on unfilled epoxy and epoxy filled with 5 wt% of nano alumina. The leakage current through the samples were continuously monitored and the variation in tan delta values with aging duration was monitored to predict the impending failure and the time to failure of the samples. It is observed that the time to failure of epoxy alumina nanocomposite samples is significantly higher as compared to the unfilled epoxy. Data from the experiments has been analyzed graphically by plotting the Weibull probability and theoretically by the linear least square regression analysis. The characteristic life obtained from the least square regression analysis has been used to plot the inverse power law curve. From the inverse power law curve, the life of the epoxy insulation with and without nanofiller loading at a stress level of 3 kV/mm, i.e. within the midrange of the design stress level of rotating machine insulation, has been obtained by extrapolation. It is observed that the life of epoxy alumina nanocomposite of 5 wt% filler loading is nine times higher than that of the unfilled epoxy.

Item Type:	Journal Article
Publication:	IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
Publisher:	IEEE
Additional Information:	Copy right for this article belongs to the IEEE
Keywords:	Electrothermal aging; polymer nanocomposites; rotating machine insulation; epoxy; life estimation
Department/Centre:	Division of Electrical Sciences > Electrical Engineering
Date Deposited:	14 Aug 2014 10:26
Last Modified:	14 Aug 2014 10:26
URI:	http://eprints.iisc.ac.in/id/eprint/49557

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