The Hysteresis Character of Corona Formation

To begin with the hysteresis character of 60-cycle corona formation was indicated by two factors: (1) the value of the crest voltage was of dominating importance in the corona loss-voltage relation and (2) the value of the power lost in coronafrom a high voltage transmission line approximated that given by the product of the voltage in excess of the critical voltage and the line charging current. Diagrams of the cyclic instantaneous voltage-charge relation in corona formation were obtained and revealed the facts that in a given case the charge lags behind the corresponding voltage by an approximately constant amount and that the energy dissipated per cycle is proportional to the product of the crest voltage and the difference between the crests of the voltage and the critical voltage. The corresponding equation for the full corona loss-voltage relation is P = 4f C (E
²
- E E
0
). 60-cycle brushes, coronas and streamers are due to the activities of ions carrying charges largely of the same sign as that of the conductors from which they emanate. The factors that control brush formation are considered. Local corona is due to an incomplete unstable brush pattern. Full corona is correspondingly due to a complete stable brush pattern. In relation hereto critical voltage, crest voltage and irregularity factor are defined.