AC Electrical Breakdown Characteristics of an Epoxy/Mica Composite

Abstract

Epoxy/mica composite was synthesized, in order to use it as an impregnation resin in a vacuum pressure impregnation (VPI) process, for manufacturing a high voltage rotary machine. The average particle size of the mica was 5~7 μm and its content was 0, 20, 30 and 40 wt%. A plasticizer or a low molecular aliphatic epoxy was also used, to decrease the viscosity of the composite. The AC electrical breakdown strength was estimated in sphere-to-sphere electrodes, and the electrical breakdown data were estimated by Weibull statistical analysis. The electrical breakdown strength became higher with the addition of mica; and that of the system with 20 wt% mica was highest. The electrical breakdown strength of the system with an aliphatic epoxy was higher than that of the system with a plasticizer.

Properties of Polymer Composites Used in High-Voltage Applications

“…Micafolium insulation systems were being manufactured in the same time as the asphaltic mica systems and at the beginning, they were applied for sheet wrapping of high-voltage coils and shaped insulating parts. Park [ 12 ] synthesized epoxy resin/mica composites and estimated their electrical breakdown, in order to use the composite materials for manufacturing the insulation systems of high-voltage machines. In particular, mica particles with dimensions of 5–7 µm and different concentrations (20, 30 and 40 wt %) were applied.…”

“…In particular, mica particles with dimensions of 5–7 µm and different concentrations (20, 30 and 40 wt %) were applied. To reduce the composites viscosity, a plasticizer or a low molecular aliphatic epoxy was used [ 12 ]. The electrical breakdown strength (measured with a sphere-to-sphere electrodes system) was increasing by the addition of mica filler and an optimum was achieved for a mica content of 20 wt % [ 12 ].…”

“…To reduce the composites viscosity, a plasticizer or a low molecular aliphatic epoxy was used [ 12 ]. The electrical breakdown strength (measured with a sphere-to-sphere electrodes system) was increasing by the addition of mica filler and an optimum was achieved for a mica content of 20 wt % [ 12 ]. The electrical breakdown strength of the system with an aliphatic epoxy was higher than of the system with a plasticizer [ 12 ].…”