| 摘要 |
<p>PURPOSE:To permit a DC pressure resistance test of a cable line without impressing a high DC voltage on an instrument by a method wherein connection between a conductor extracting rod and an internal electrode is cut off electrically when a bushing is extended. CONSTITUTION:An internal electrode 14, connected electrically to the connecting terminal A and the charging terminal B, and a conductor extracting rod 13, connected to the internal circuit of an instrument, are provided in a bushing 11. The bushing 11 is provided with a contractable unit 15 to put electric connection between the internal electrode 14 and the conductor extracting rod 13 ON/OFF. Upon the DC pressure resistance test of the cable line 20, the contractable unit 15 is extended to put the electric connection OFF. Accordingly, connection between the conductor extracting rod 13 and the cable connecting terminal A is intercepted electrically whereby a DC testing voltage is impressed on only the cable line 20. According to this method, the DC pressure resistance test of the cable line 20 can be effected without impressing any high DC voltage on the instrument.</p> |
