Development of a mold resin for molded transformers and its mechanical and insulating characteristics

To obtain a low-thermal-expansion mold resin, various tests to obtain the most suitable coupling agent for the resin were carried out. As a result, the mixture of titanate and silane type coupling agents allowed an increase in filler content to higher than 60% in volume. The developed mold resin showed a thermal expansion coefficient as low as that of aluminum and had excellent resistance to cracking. Finally, it was confirmed that the mechanical strength, dielectric strength, and E-t characteristics of the developed resin were superior to those of the conventional one.<
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