Surface modified nano-SiO2 enhances dielectric properties of stator coil insulation for HV motors

Nano-SiO2 particles were doped into epoxy resin (EP) to fabricate the main insulation used for high voltage (HV) motors. The EP-based nanocomposite with different mass ratios of nano-SiO2 particles (0.5, 1, 2.5, and 5 wt%) were prepared. Surface morphology and conductivity of samples were tested, and AC breakdown strength was measured at different temperatures. The mechanisms for the tailoring of dielectric properties of EP were discussed. The optimal doping scheme (0.5 wt%) was selected and used as the base material in preparation of a stator coil insulation for 6 kV motors. The dielectric properties, including dielectric loss and leakage current as well as partial discharge, were tested, and the potential application of nano-SiO2 particles in the stator coil insulation of HV motors was discussed. The test results showed that the doped nano-SiO2 particle into dielectric composite used as the main insulation material for HV motors can be an optimal candidate to improve the above mentioned properties especially dielectric losses and electrical breakdown strengths. The results in this paper offer references and a guiding significance for the application of nano-SiO2 in the insulation of HV motors.