Chemical developments in the field of insulation

The significance of teats applied in the study of the deterioration of mineral insulating oils is discussed in an article by J. C. Balsbaugh and J. L. Oncley (1). In addition to some mineral oils, decalin, tetralin, and cotane were oxidized and their electrical, chemical, and optical properties were measured. The synthetic hydrocarbons studied had much lower dielectric losses for a given amount of oxygen consumed than the group of oils studied, showing that it is the nature of the oxidation products formed, rather than the oxtent of oxidation, which is important. The relative change in light transmission of the oxidized samples appeared to be a good indication of electrical deterioration.