Technological factors of insulation systems for large rotating machines: influence on thermal and electrical properties

The composite materials consisting of mica paper, fiber glass and epoxy resin are widely used for the insulation systems of large rotating machines. The combination of such materials creates the desired insulation system properties and protect material from being simultaneously subjected to thermal, electrical, chemical and mechanical stress. The special technological parameter of insulation - density (Pl) is introduced. Dependence of thermal (thermal conductivity) and electrical properties (Eps, tg δ and breakdown strength) of composite materials, which are commonly used in insulation systems for large rotating machines from the parameter Pl are discussed in this paper.