The Dielectric Strength of Noninflammable Synthetic Insulating Oils

The development of synthetic noninflammable chlorinated liquids of the aromatic hydrocarbon type places in the hands of the engineer a chemically stable material of high dielectric strength and possessing a dielectric constant approximately equal in value to that of cellulose itself. This insures a more equitable stress distribution in the composite insulation assembly normally used in commercial practice. The result is an increase in dielectric breakdown and related phenomena. No fixed relation defining the superiority of the synthetic noninflammable liquid or liquid-treated insulation is possible, since variation in test conditions changes the relative dielectric values. In general, however, the data indicate an advantage in favor of the synthetic liquid and liquid-treated insulation equal to at least 20 per cent of the corresponding mineral-oil value.