Study on charge transport mechanism in polyimide films

As a core component of ac drive electric locomotive, performance of inverter-fed motor directly influences the stability and reliability of locomotive running. However, insulation early failures occur frequently. Presently, polyimide film, as a special type of engineering plastic film, widely applied in turn to turn insulation and turn to ground insulation of inverter-fed motors is a kind of basic insulating material. This paper investigates charge transport mechanism in polyimide films based on measuring and comparing space charge accumulation threshold field between corona-resistant and common polyimide films. The results reveal that space charge accumulation threshold field of corona-resistant polyimide film is higher than that of common polyimide film; the adding of nano-particles effectively increases dielectric properties of corona-resistant film.