Effect of inter-layer pressure on dielectric breakdown characteristics of metallized polymer films for capacitor applications

Relatively high level of inter-layer pressure is often promoted for wound metallized film capacitors as it has been found to reduce the capacitance loss during self-healing breakdown. However, the effect of inter-layer pressure on the dielectric breakdown strength of metallized polymer films is not well documented and further analysis is needed. In this study, the effect of inter-layer pressure on the dielectric breakdown characteristics of various metallized polymer films is studied. By utilizing low-energy self-healing breakdown, multiple breakdowns can be measured per sample film. The results suggest that high inter-layer pressure has a negative impact on the breakdown characteristics of the metallized films studied and, in the worst case, may lead to insulation resistance failure.