Properties of Castor Oil Impregnated All-Polypropylene and Polypropylene-Paper Capacitors

In view of its non-toxicity, and good dielectric properties, castor oil, a polar liquid dielectric of vegetable origin is suggested as a possible alternative to PCB´s for capacitor applications. In this paper the dielectric properties (including partial discharge behavior), of all-polypropylene and paper-polypropylene capacitors with castor oil as impregnant, are reported. The paper also contains results of life studies conducted under accelerated electrical and thermal stresses when they are occurring both individually and combined. The data obtained have been statistically analyzed and approximate life of the system calculated by linear extrapolation.