Impregnated paper insulation

THIS abstract of a preliminary report gives some results of a study of the life of impregnated paper insulation under way at the School of Engineering, Johns Hopkins University. The work is being supported by the subcommittee on impregnated paper-insulated cable research of the National Electric Light Association. In an earlier work under the same auspices, a study was made of the influence of residual air on dry impregnated-paper insulation. Results of that study (Vol. 47, No. 1 Transactions A. I. E. E., January, 1928) showed the desirability of investigating the effect which different amounts of residual air would have upon the life of impregnated paper insulation. A brief summary of the results so far obtained is given here in the form of eight conclusions, briefly qualified.