Gas breakdown mitigation in satellite slip rings

Direct current (DC) gas breakdown is experimentally investigated for high-voltage circular conductors and insulators that reproduce the main features of a satellite slip ring. Breakdown voltages are measured in the pressure range 10−3–10 mbar, where gas breakdown is predominant with respect to vacuum breakdown. The measured breakdown curves show clear similarities with Paschen's curve, which is generally associated with parallel plate electrodes. It is shown that the low-pressure branch of the measured curves is determined by breakdown between the high-voltage ring and the grounded vacuum chamber, whereas the high-pressure branch is due to discharges between the high-voltage ring and the adjacent grounded rings. A technical solution is introduced to inhibit the gas discharges at low-pressures in a slip ring assembly: The diameter of the grounded conducting discs is extended, strongly increasing the measured breakdown voltages by modifying the electric field distribution. The safe operating pressure range of the satellite slip ring is thereby increased by two orders of magnitude.