Tanδ temperature spectroscopy of mica tape binder

For the past few decades, the design trend for high voltage rotating machinery has been toward greater capacity, longer service life, more reliable operation, and higher voltage levels. Two kinds of insulation system have been applied: the vacuum pressure impregnation (VPI) and the rich resins. Although the VPI insulation system has good properties, the rich resin binders are still being paid wide attention. This paper describes the dissipation factor temperature spectroscopy for several kinds of rich resin micapaper tape binders being used in China. Changes of tanδ of epoxies cured with Tung oil anhydride, modified bismaleimide and metal carboxylate are different. With adding modified bismaleimide the heat resistance of the binder is improved. Tanδ is high when using metal carboxylate at high temperature. By reducing dosage and improving reaction activity tanδ will be a low value at high temperature. The epoxy resins discussed in this paper are bisphenol A epoxy E44 and novolac epoxy resin F44 produced in China. The values of tanδ are obtained at 1 kV and 50 Hz