Determination of critical distances measuring in needle-plane electrode arrangement with dust layer

Several examinations with needle-plate arrangement have been performed during the last few decades to examine discharge developments, particle charges processes or separation. When industrial dust can be found on the plate, the charges accumulate on the surface. Experiments on how much charge can be accumulated or breakdown voltages were calculated, back corona effects were investigated before. Due to the high voltage (corona) electrode, high electric field has a significant effect on dust particles. The effect consists of the Coulomb force and the ionic wind. As a result, the resulting electrohydrodynamic flow can entrain the dust particles from the plate surface, modifying the proper measurements. In addition, small craters can be formed, affecting the initial electric field distributions. The research aimed to determine main parameters like electrode distance, needle length and applied electrical parameters, which significantly affect the needle-plate measurements.