The Power Loss in Condensers with Liquid Dielectrics

Abstract

Power loss in condensers with liquid dielectrics; variation of equivalent series resistance and capacity with frequency, 600 to 3500 cycles.---Using a variable test condenser with conical plates nickel plated, measurements for frequencies below 3700 were made with a special capacity bridge previously described by MacLeod, and for higher frequencies to 1,500,000 cycles by an ordinary resonance substitution method. Castor oil, benzene, xylene, toluene, olive oil, paraffine oil, medicinal oil, "Bostonia," glycerine and oil of turpentine were studied; results are given for the first five. The power loss per unit voltage $R{\ensuremath{\omega}}^{2}{C}^{2}$ is approximately constant for benzene, xylene and toluene, decreasing only from 202 to 184, from 102 to 90 and from 138 to 117 (all times ${10}^{\ensuremath{-}10}$ watts), respectively, as the frequency increased from 700 to 3500. This indicates that the loss is due chiefly to conductivity, but in some liquids, notably xylene, there is apparently a small additional loss which decreases with the frequency but which does not fit the equation for dielectric absorption. Castor oil and olive oil show a loss per unit voltage increasing with frequency, suggesting two leaky condensers in series.