AC Breakdown behavior at Sub-millimeter Air Gaps

Breakdown of air gaps of few millimeters have been studied under AC voltage, 50 Hz by using different electrode configurations. Different electrode configuration (using commercially available thin razor blades, needle- plane, 2 hemispheres) have been studied in the gap regimes of 100 µm to 1 mm. The present work aims at verifying the values of breakdown voltages for 1mm gap for blade electrode. Efforts will be made to reduce the gap as accurately as possible and study the breakdown behavior. In the present work, optical flats are used to ensure parallelism or planarity by placing the blade electrodes in horizontal manner, so that investigation can be conducted with one-dimensional planar electrodes. Observations were carried out with the help of magnifying glass. The effect of electrode material was also studied by changing one of the electrode material while conducting experiments with needle plane setup and observed results are extensively studied and reported. Such an approach is expected to prove helpful in explanation of breakdown voltages and the current inception voltages which may arise in micro electromechanical systems (MEMS) in the course of their operation and lots of other related fields Keyword: Electric breakdown, partial discharge, microelectrodes, electric field.