Experimental characterization of a tri-needle-type corona electrode
Résumé
Previous studies had shown that the distribution of charges generated by corona discharge is controlled by several factors such as the geometry of the electrode system and the level of the applied voltage. The aim of this paper was to evaluate the uniformity of charge distribution at the surface of dielectric materials (PVC plates and PP films) exposed to a corona discharge generated by a tri-needle-type electrode at rest or in motion. The surface electric potential mapping performed with a non-contact electrostatic voltmeter shown that the non-uniformity of the corona charge is related to the geometry of the electrode employed in the experiments and can be reduced to less than 5%, when choosing the appropriate values for the distance between needles and for their height above the samples. It was also found that exceeding a certain value of applied voltage accelerated the surface potential decay, a phenomenon that explains the deterioration of charge uniformity.