Design of a cylindrical high-voltage high-temperature vacuum insulator

A design for a high temperature, HV insulator is presented. This design exploits the temperature dependent thermal and electrical properties of alumina and a unique structural insulator design to increase the high voltage hold-off characteristics of the insulator, reduces thermal flux through the insulator, and alleviate stresses caused by mismatch between insulator and electrode thermal expansion coefficients. The designed insulators insulate graphite electrodes at temperatures approaching 1000 C and potentials up to 50 kV. In this paper, the general methodology of designing these insulators is explored, and some limited performance data is presented.