An Investigation of the Arc-Quenching Behavior of Sulfur Hexafloride [includes discussion]

Sulfur hexafluoride, a stable gas which is markedly superior to air in dielectric strength, is shown to be superior to an even higher degree as an arc-quenching atmosphere. The a-c interrupting ability of plain-break arcs in SF6 is in the order of 100 times that of similar arcs in air. Limiting current values for plain-break interruption increase in a roughly linear manner with both arc length and gas pressure. Results with SF6 air mixtures lie between those for the pure gases. Large improvement over the plain-break results may be obtained by moderate rates of forced gas flow through the arc space. The experimental results obtained so far give promise of practical usefulness for SF6 in sealed interrupters for moderate currents at high voltages.