Tests on oil-impregnated paper — II effects of gas pressure

In 1934 tests were started to investigate the important factors influencing the life of oil-impregnated paper at high voltage. Last year we described the techniques developed to date in this investigation. The present paper presents all data taken on specimens tested under a gas pressure of 200 pounds per square inch and compared all results obtained with one commercial mineral oil and one commercial wood-pulp paper for 3 conditions of gas pressure. The results indicate that under the conditions of these tests there is no correlation between dielectric loss and electrical life and that gas-free specimens are superior to any specimens saturated with gas up to 200 pounds per square inch pressure.