The electrical properties of filled and unfilled commercial epoxy resins

An investigation of an epoxy resin of the type used in electrical machines filled with various concentrations of ZnO or Al/sub 2/O/sub 3/ has been made using current transient measurements. It is shown that the addition of either aluminium oxide or zinc oxide filler can produce a composite material with a nonlinear resistivity characteristic when subjected to electric fields up to 11 kVmm/sup -1/.