| 摘要 |
PURPOSE:To enable obtaining an average contaimination degree between electrodes, by a method wherein a plural number of sets of parallel electrodes are located in a radial manner from approximately a center at an under surface of a pilot insulator whose shape and surface conditions are equal to those of an insulator for practical use. CONSTITUTION:Sets of parallel electrodes [(2A-1), (2B-1)], [(2A-2), (2B-2)]... are placed in a radial manner fron nearly a center at an under surface of a pilot insulator 1 used based on a practional use, and are connected together in parallel, being led to a contaminating amount measuring device (not shown) through a lead wire. The radial arrangement of the parallel electrodes permits obtaining of an average contamination degree between the electrodes, since a difference in an adhesion concentration of contaminants in the lateral direction of the electrode is hardly found even if a difference in an adhesion concentration of contaminants in the longitudinal direction of the electrode exists. |
