SURGE VOLTAGE PROTECTION ARRANGEMENTS

摘要

A surge voltage protection arrangement for a load 10 connected to an A.C. supply 8 comprising a gas-filled excess voltage arrester 11 connected in series with a capacitor 12 across the load 10. The value of the capacitor 12 is chosen such that the largest expected surge pulse which causes the arrester 11 to fire will not charge the capacitor to such an extent that the voltage then applied across the load 10 exceeds that of the A.C. supply 8. The arrangement enables the arrester 11 to recover after such a surge pulse within a fraction of an A.C. supply cycle, thus avoiding placing an unnecessary load on the arrester. A resistor 13 whose resistance is of a value such that the capacitor 12 is able to discharge through it within one half cycle of the A.C. supply may be connected across the capacitor 12.