| 摘要 |
1318793 Testing electric cables INDUSTRIE PIRELLI SPA 2 Oct 1970 [7 Nov 1969] 46951/ 70 Heading G1U In apparatus for testing a polyethylene-insulated stranded telephone cable by passing it through a high voltage electrode 11, the insulation is precharged before it enters the electrode 11 by an auxiliary electrode 13, so that the insulation charging current does not mask fault currents which flow from the electrode 11 due to voids in the insulation. Both the electrodes 11, 13 are connected to the same d.c. source, but only electrode 11 is connected to a fault current detector which arrests the cable movement when a void is detected. The electrode 11 comprises an annular knifeedge 28. The electrode 13 and a further, earthing electrode 12 beyond the h. v. electrodes both comprise a plurality of suspended chains 21, 22, which contact the cable insulation, and a conductive semi-cylindrical base part 12', 13' the earthing electrode 13 also including a resilient conductive tongue 23 for contacting the cable. The three electrodes and their connectors 18-20 are embedded in a transparent acrylic resin body formed of two separable halves 10', 10" and having a cylindrical aperture for the cable, the body being mounted between the stranding die and lapping head of the cable-making apparatus. |
