Onset voltages of fore and back coronas in point-plane gaps

A quantitative model is developed for determining the onset voltages of lore and back coronas in point-plane gaps. The back corona occurring inelectrostatic precipitators is studied taking into account, instead of a dust layer, samples of bakelite plates with a pinhole. The onset voltage of the fore corona isthe critical value of the applied voltage which yields a self-sustaining dischargefrom the stressed point. The model lor determining the onset voltages of the backcorona involves the solution of the governing set of equations; namely, Poisson’sequation, the equation for current density, the current continuity equation and thebreakdown condition of the dust layer. The calculated onset voltages arecompared with those measured experimentally. Results of other investigators arediscussed in the light of the present findings.