Effects of Magnetic Field on Surface Dielectric Breakdown of Contaminated Printed Wiring Board

Abstract

With the development of miniaturization and high accumulation of electrical devices, the demand for insulation reliability of printed wiring boards that are installed in these electric and electronic parts is rising. In recent years, there is an increasing need for electrical devices in various complex field environments, which include magnetic field and electrical field. Accordingly, it is necessary to investigate the influence of complex fields on surface insulation breakdown of printed wiring board. In this paper, surface dielectric breakdown phenomena of contaminated printed wiring board under dc magnetic fields were investigated. We employed a dc magnetic field which was made at 100mT, 200mT, 300mT and then up to 500mT according to the laboratory target. The relationship between the number of electrolyte drops to insulation breakdown and relative angle between magnetic field and electrical field was examined. The relative angle between magnetic field and electrical field was 0, 90 and 270 degrees. Loading electrolyte drops between the two electrodes on the sample surface made humid conditions. The study revealed that leakage current increases with 270 degree and decreases with 90 degree under 300mT. The number of drops to breakdown decreased with 270 degree and increases with 90 degree with increasing magnetic fields. Discharge current characteristics under different magnetic field conditions were discussed by using a wavelet transform. The results indicated that the scintillation discharge energy showed a tendency toward increase with 270 degree and decrease with 90 degree when applied magnetic field was applied under 200mT. It is considered that the area of scintillation discharges occurrence was changed by application of electromagnetic force.