Abstract :
The results of tests made on 9 viscous mineral oils of various types and on mixtures of these oils with 8 resins are presented. The physical and electrical properties, stability to oxidation, and stability to gaseous ionization are correlated with the viscosity index and chemical composition of the oils and resins. The catalytic effects of metals on oil oxidation are studied. Gaseous ionization in insulation voids is found to exert a physical pressure and to accelerate saturant oxidation.