page_224

< previous page | page_224 | next page >

Page 224

| This arrester has another feature called an isolator (Fig. 12-5). It consists of two auxiliary electrodes between which combustible powder is placed, the whole apparatus being sealed in plastic. If the valve element is damaged, the heat produced will ignite the powder and the expanding gases will rupture the housing. The ground lead attached to the lower electrode is disconnected from the arrester and hangs visibly below it. Thus disconnected, the damaged arrester prevents a long outage to the line or equipment to which it is connected. Although obsolete, many will remain in service for a long time. |

| Figure 12-5 Granulon (isolator) arrester. |

< previous page | page_224 | next page >