Effect of Humidity on Electrical Characteristics of an Arc in Air at Normal Flight Altitudes

A popular technique for arc detection in aircraft electrical power systems is current signature analysis, which relies upon predictable current/voltage characteristics of electrical breakdown of a gaseous gap. Measurements were made of electrical characteristics of arcs in air at various humidity levels at pressures corresponding to sea level and 60,000-Ft (18.3-km) flight altitude. Variations in humidity introduced by uncontrolled laboratory air, even when water-vapor levels are well above those expected at temperatures
$< 0 \ \mathrm{C}$
, were shown to have insignificant effects while employing the current signature analysis technique.