Dielectric Properties of the Composite Insulator Mica Epoxy-Novolac

Abstract:

As electric insulators of the copper conductors in the electric generators of alternative current or in electric motors of high tension, there are used with priority the composite crosslinked mica-epoxy. Pre-impregnated band with solvent was introduced, the impregnation being performed with phenolic-novolac resin. The studied material got superior dielectric properties at function temperatures corresponding to the insulation class F(155C). Its main components are: mica paper (53%), glass cloth (13%) and the basic epoxy phenolic-novolac resin. The complex permittivity and conductivity were determined with the Time Domain Spectrometer (TDS); the apparatus allows the determination of the electric values in the domain of frequencies: very large domain of frequencies. The temperature varied in the domain 23-190C with the help of an oven. The purpose of this article is to report the dielectric properties of mica-epoxy-novolac composite insulator, for which very few data have so far been published.

• Periodical: Advanced Materials Research (Volume 701)
• Pages: 47-52
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.701.47
• Online since: May 2013
• Authors: Doina Elena Gavrilă, Horia Catalin Gavrilă
• Keywords: Complex Permittivity, Composite Crosslinked Mica-Epoxy, Conductivity, Electric Generator Ac Current, Frequency, Insulator Class F, Phenolic Novolac Resin, Time Domain Spectrometer

References

[1] A. Svatik, V. Adamek and J.H. Calderwood, Int. Conf. on Dielectr. Mater., Canterbury, UK (1988), p.262.

[2] R. Fournié , Les isolants en électrotechnique, Chapter 6 ( Editions Eyrolles, Paris 1990).

[3] A.R. von Hippel, Dielectrics and Waves, (MIT Press, Boston MA 1954).

[4] R.W. Sillars, Electrical Insulating Materials and their Applications, (Peter Peregrinus Ltd., London 1974).

[5] M.R. Wertheimer, L. Paquin, H.P. Schreiber and S.A. Boggs, IEEE Trans. Electr. Insul. EI12, (1977) p.137.

[6] L. Paquin, H. St-Onge and M.R. Wertheimer, IEEE Trans. Electr. Insul. Vol. EI-17, (1982) p.399

DOI: 10.1109/tei.1982.298482

[7] M. Meunier, J.F. Currie, M.R. Wertheimer, and A. Yelon, J. Appl. Phys. 54 (1983) p.898.

[8] M.R. Mitroi, V.Iancu, Doina Gavrilă , Mod. Phys.Lett.B,17(7), (2003), pp.273-279.

[9] D.Gavrila, Proc. 15-th International Conf. Dielectric and Insulating Systems in Electrical Engineering, Slovakia, 4-8 Sept.,2004, Casta Pila, Slovakia, pp.95-99.

[10] N.G. McCrum, B.E. Read and G. Williams, "Anelastic and Dielectric Effects in Polymeric Solids", (J. Wiley and Sons, New York, 1967).

[11] P. Hedvig "Dielectric Spectroscopy of Polymers", (J. Wiley and Sons, New York 1977).

[12] T.Tanaka, S. Hayashi and S.Shibayama, J.Appl. Phys. 48, (1977), 3478.