Some electrical and thermal characteristics of helium and sulfur-hexafluoride mixtures

The results are presented of a study of some of the electrical and thermal properties of mixtures of helium and sulfur-hexafluoride which are compared with the pure gases: air, hydrogen, helium, and sulfur-hexafluoride. It is shown that the addition of relatively small amounts of sulfur-hexafluoride to helium will result in an electric strength greater than that of air and of hydrogen. The thermal properties of such mixtures are nearly as good as hydrogen. The mixture is attractive as a cooling and insulating medium for both static and rotating machines. Such a mixture is very safe whereas hydrogen presents an explosive hazard. Permeation losses through metal containers are much less than for hydrogen.