VALVE TYPE VOLTAGE ARRESTER DEVICE

摘要

VALVE TYPE VOLTAGE ARRESTER DEVICE A low voltage valve type arrester device for connection between a domestic electric supply line and earth includes a varistor, a switching device and an encapsulated gas discharge voltage arrester connected in series. The switching device includes two switch members connected together by a solder connection and biased apart by a spring. A fusible link is connected to the two switch members in parallel with the solder connection. When a voltage surge occurs, current flows through the arrester to earth. If the surge is large enough to render the gas discharge arrestor continuously conductive the solder connection melts due to the heat dissipated in the varistor and the two switch members move rapidly apart. The fusible connection rapidly melts by which time the switch members are sufficiently far apart for no are to form between them.