Uretrane elastomers for the control of very high d.c. voltages

The technique of voltage grading a surface which is stressed electrically to very high d.c. voltages was experimentally shown to be a sound approach in the design of pressurized gas-to-vacuum feed-through bushings. A maximum voltage of 1.2 million volts positive and 1 million volts negative were realized over an insulator length of 30 cm in vacuum.