| Epoxy Resin is widely used as the insulation of electric and electronic devices for its great dielectric properties. In the process of Develop Western Regions, devices have to operate on high altitude regions above 4000m, where the ambient pressure is very low. As a result, the dielectric properties of epoxy resin are changed. At the same time, there is always magnetic field around transformers, reactors and etc which makes dielectric breakdown of epoxy resin in the devices and finally results in serious failures. However, effect of magnetic field on dielectric breakdown has not been sufficiently studied on epoxy resin. Therefore, from the safety point of view, it's very important for us to investigate the influence of low pressure and magnetic field on dielectric breakdown of epoxy resin.In this paper, epoxy resin laminate on which copper electrodes was printed has been employed to investigate the effects of low pressure and magnetic field on the dielectric breakdown. The experiment was carried out under electric and magnetic field by using a DC power under decreased pressure conditions. The test results show that with decreasing the pressure, the time to dielectric breakdown increases, the inception voltage decreases. The value of inception voltage is smaller under magnetic field than that of non-magnetic field. The time to dielectric breakdown under magnetic field depends on the direction of E×B. When E×B drifts into the surface of epoxy resin, the time to breakdown is shortened. When E×B drifts away from the surface of epoxy resin, the time to breakdown is delayed. Furthermore, the influence of magnetic field on dielectric breakdown depends on ambient pressure and electrode pattern.
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