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Journal of Microwave Power and Electromagnetic Energy, 49 (3), 2015, pp. 171-181. A Publication of the International Microwave Power Institute Microwave Reticulation of Epoxy Resins Used for Single Layer Electric Insulations Francisc Ioan Hathazi, Mircea-Nicolae Arion University of Oradea, Faculty of Electrical Engineering and Information Technology, Department of Electrical Engineering, 1-5 University St., Oradea, Romania Daniela Iordache National Research and Development Institute for Energy – ICEMENERG, 8 Energeticienilor Blvd., Bucharest 3, Romania Received: June 19,2015 Accepted: September 3, 2015 ABSTRACT The main objective of these experiments is to identify the possibilities for proving a microwave technology for thermal reticulation of electric insulations deposited on metallic supports. To avoid the occurrence of phenomena that could affect the integrity of the microwave generator, the system has been equipped with a load for absorbing the residual power in microwaves. The charge placed in the applicator is made of a microwave - transparent plastic coil through which water circulates. The insulating material used during the experiments was P772 special tape impregnated in epoxy resin deposited on a metallic support through rolling. The quality of the electric insulation obtained by means of the microwave technology is better compared with the conventional methods. KEYWORDS: Epoxy resins; microwaves; electric insulations; single layer, insulating tape. INTRODUCTION Insulating materials play a major role in reliability of low, medium and high voltage equipment and devices. They represent an evolving class of materials, enabling progress especially in macromolecular chemistry and determining the lifetime of appliances and electrical machinery. Insulating materials are those materials that present polarization under the action of the electric fields. Polarization occurs as a consequence of the limited movement of electrons or ions under the action of the forces generated by the electric field. Due to limited movement of the electric charges, the insulating materials have very low electrical conductivity and high resistivity, respectively. The main function of insulation is to prevent the electric current flow between conductors that might have different electric potential. That is why it is necessary to provide electrical insulation and the physical separation of conductors. An important role of insulation is to enable the heat transfer because most of the electric drives generate heat during normal operation [Ueta et al., 2012]. This heat must be adequately removed in order to avoid the excess heat accumulation that may lead to the destruction of the equipment. Therefore, in some applications, the thermal conductivity of the insulation may be more important than its mechanical and dielectric properties. In recent years thermosetting coatings based on epoxy resins have been increasingly used because of their performances [Li et al., 2011]. Regardless of the place where they International Microwave Power Institute 171