A criterion of quality of cable insulation

Oil oxidation in impregnated paper

“…Power factor tests of paper layers following oxidation runs show no increase in layers next the electrodes in the one-millimeter speci mens, a very slight rise for the 5-centimeter specimens, and a definite rise above average values only for oxygen contents above 0.7 per cent by volume (5 centimeters pressure of oxygen impregnation). 10. The evidence of these tests is that the continued process of oxidation rather than the products of oxidation is the cause of oil and paper deterioration.…”