| Research Abstract |
Silver and copper migration, under the influence of a dc voltage, have been observed through the surface of a dielectric ceramic(CD) used as high voltage condenser and three kinds of organic insulating materials such as phenolic paper laminate(PL), epoxy resin contained glass fiber(GE) and polyester contained glass fiber(GMP). The test condition was 60゜C and 80% R.H. The dielectric ceramic was applied 250 V dc and the organic Insulating materials were applied 100 V dc.
At first, the water content was measured for all materials. The water content of PL was found to be 1.4 % during 100 hours. On the other hand, the dielectric ceramic was found to be below 0.05 %. GE and GMP were about 0.2 %.
There was no migration phenomenon for dielectric ceramics. It was found, however, that the silver migration for PL was easily occurred as compared with that for GE and GMP. The surface resistivity for PL was abruptly reduced against the application time of voltage. This is because the paper in PL easily adsorps water.
On the other hand, no migration was found for copper electrode even PL during 200 hours.
There was found a little migration for PL coated with epoxy resin during 300 hours. It seems that epoxy resin supresses the absorption of water.
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