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Page 221

| Figure 12-2 Pellet arrester. |

| Autovalve Arrester.. |

| In the autovalve arrester (Fig. 12-3), the valve element is made up of ceramic material and conducting particles. The arrester consists of a stack or column of flat discs or electrodes made of this material and separated by thin insulating mica washers; the column is connected through a series gap to the line and ground. At voltages above the critical value, the short gap between the discs breaks down and current flows. Since the discs are thin and of relatively large area, the resistance through which the discharge current flows is low, even though the resistivity of the discs is comparatively high. When the voltage falls below the critical value, no current will flow and the arrester is returned to its nonconducting state. |

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