Effects of corona and spark-over in Freon

Gases are being used to an increasing extent as insulating media for high-voltage equipment; this article reports the results of tests of the chemical stability of Freon, which has been found most satisfactory in such applications. PERHAPS the most effective means of increasing the compactness of high-voltage apparatus is the use of insulating media of higher dielectric strength. With the development of ultrahigh-voltage equipment^1,2 a number of gases have been examined as to their qualifications as dielectrics. Among these is Freon, CCl2F2, a gas having a dielectric strength about three times that of air at the same pressure^3,4,5 and a vapor pressure of 85 pounds per square inch absolute at 20 degrees centigrade. It is nonpoisonous, nonflammable, and noncorrosive under normal conditions.