Some experiments on positive point-to-plane corona and spark breakdown of compressed gases

Abstract

A test pressure vessel for the investigation of electrical discharges in gases at pressures up to 1 000 lb/in² is described.The electrical insulating properties of compressed air, nitrogen, dichlorodifluoromethane (commercially known as Freon 12 or Arcton 6) and sulphur hexafluoride, as well as certain mixtures of these gases, are compared; a hemispherically-tipped point-to-plane electrode configuration and direct voltages were used. Pronounced maxima obtained in the spark-breakdown-voltage/gas-pressure characteristics for the electronegative gases and gas mixtures are shown to be associated with the establishment of corona at the anode.Corona-current/voltage characteristics for some of the gases tested are included.