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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
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