Enhancement effect of approach speed of grounded metal plate on breakdown potential gradient in air discharges of electrostatic generator

Using a velocimeter based on the laser Doppler effect, we measured spark lengths by moving a grounded metal-plate to an electrostatic discharge generator with charge voltages from 1000 V to 8000 V at three different approach speeds of 20 mm/s, 100 mm/s and 200 mm/s. As a result, we found that with increasing the approach speed, spark lengths decrease, while the resultant breakdown potential gradient or the charge voltage divided by the spark length exponentially increases. © 2016 The Institute of Electrical Engineers of Japan.