Some experiments on a high-power closing switch with polythene as the main dielectric

A switch consisting basically of a polythene sheet between two electrodes has closed successfully on pulses of up to 430kA and up to 170 coulombs, at up to 40kV. The switch is triggered by a high-current discharge from an auxiliary electrode.The polythene was stressed at up to 800 V/cm without puncturing prematurely. The closing time of the switch was approximately 2 μper millimetre of polythene, and this time was not affected significantly by varying the voltage across the switch at the instant of closing from 0.01 to 400kV/cm.The position of the main discharge on the electrodes was controlled, and they eroded fairly uniformly over a large area. With Heavy Alloy electrodes, the rate of erosion was of the order of 0.1 mm3/coulomb-pulse per electrode. Details are given of an arrangement for replacing automatically the polythene and other expendable parts of the switch.