Some properties of two EPON® resin systems for use as electrical encapsulants

Since the announcements in mid 1961 that certain electrical equipment manufacturers had succeeded in encapsulating distribution transformers with an epoxy resin system, it has become a well known and widely discussed fact that a major breakthrough has been achieved in the field of power distribution equipment. After many years of searching for high quality insulating resins and unit designs to replace the conventional massive and heavy oil-filled tank, epoxy resin systems meeting Class B requirements, and higher, have been developed which are rated at 80° C average winding temperature rise with dielectric properties equivalent to those of conventionally constructed transformers.