Behavior of Dielectrics A Study of the Anomalous Charging Current and the Variation of Dielectric Energy Loss and Capacitance with Frequency in Solid Dielectrics

Abstract

The paper describes a research undertaken with the object of throwing light on the relations between the electrical properties of dielectrics or insulating materials, especially on the relation between the ``anomalous charging current'' under a direct voltage test and the dielectric energy loss for an impressed alternating voltage. After a review of the theory of this relationship, the methods developed in this study for observing the anomalous charging current in condensers in the time range from 0.0007 to 0.100 seconds after impressing a steady potential are described. The methods used in observing the ``normal leakage current'' and the alternating energy loss and capacitance in the frequency range from 200 to 4000 cycles per second are also described. The results of measurements by these methods on mica, glass, varnished cloth, and paraffin paper condensers are given. These measurements include a series giving the effect of varying temperatures on the properties of the glass and varnished cloth condensers. Finally, the comparisons between the dielectric energy loss and capacitance variation with frequency predicted on the basis of the d-c. anomalous charging current tests and the variations which were actually observed are given. These comparisons show that a fair agreement exists between the predicted and observed curves.