| 摘要 |
PURPOSE:To improve accuracy in the detection of a disconnection and to make the detection at the initial stage of the disconnection sure by measuring a high frequency resistance with the use of a high frequency current and correctly detecting the condition of an outer surface where the disconnection is most easy to generate. CONSTITUTION:A value of 1/R, the inverse of a resistance R when the high frequency current is made to flow to a cable for movement having no disconnection, is shown by a line (a), and the value of 1/R when a D.C. is made to flow to the same cable is shown by a line (b). By inclinations of the line (a) and the line (b), the resistances of the line (a) are recognized to be larger and the resistance increase caused from a skin effect of the high frequency current is indicated. Also by a line (a'), the value of 1/R when the high frequency current is made to flow to the cable for movement having a disconnection rate of about 10% is shown, and by a line (b'), the value of 1/R when the D.C. is made to flow to the same cable is shown. The resistance increase is more remarkable in the case of the high frequency current as compared with the case of the D.C., and the generation of the disconnection on the outer surface of the conductor can be more correctly detected with the high frequency current than D.C. |
