Experimental characterization of electric potential uniformity at the surface of polymer plates corona charged by multiple-row needle-type electrodes

Diverse configurations of needle-type electrodes are commonly used to generate DC or AC corona discharges in various industrial applications. Previous studies confirm that the amount of charges generated by corona discharge is controlled by several factors such as the level of applied voltage, the ambient conditions, as well as the geometry of the electrode system. This paper aimed to evaluate the distribution uniformity of the charges generated by multiple-row needle-type electrodes and deposited on the Polyvinyl Chloride (PVC) plate surface, either at rest (“static” regime) or in motion (“dynamic” regime) under the corona electrode. The potential at the PVC plate surface was measured by a non-contact electrostatic voltmeter. The electric potential maps resulting from the experiments carried out in “static” regime, point out that the uniformity of the corona charging effect generated by the electrodes is related to their geometry and the level of the applied voltage. In the “dynamic” regime experiments, the surface potential profiles show that the distribution of electric potential on corona-charged polymer plates depends on the number of needles and the direction of movement under corona electrode system. Comparing the results obtained in this paper with the results obtained in previous studies, lead us to a general conclusion that the uniformity can be improved, to attain values higher than 95%, and this depends on the geometry of the electrode system and on the direction of the movement of the polymer plates in the electric field.