Frequency Acceleration Characteristics in Internal Discharge Endurance Tests by a Glass-Covered Electrode System

Discharge endurance life tests were conducted at frequencies from 50 Hz to 5 kHz using a partially ventilated void with a glass barrier on one side and the plaque of the insulating material on the other. This system produces reproducible results, and, with certain reservations, the number of cycles of voltage to failure is seen to be constant. That is, frequency acceleration can be used. The upper frequency limit depends on the material and the oxygen content of the discharge space. Materials which strongly absorb oxygen have low upper frequency limits. Temperature rise due to discharge had negligible effect on lifetime at frequencies below the upper limit. Despite the insensitivity of lifetime (in cycles to failure) to frequency, tests of luminosity of the discharge, of visual observation of degradation patterns, and of discharge magnitude indicate that frequency effects are present.