Electrical installation protecting device e.g. lightning arrester, has pre-trip circuit with active part inducing voltage at one elementary spark gap greater than that at another gap to form electric arc in former gap

摘要

The device has a pre-trip circuit (10) with a control unit to control sparkover of a main spark gap (E1) that is divided into elementary spark gaps (G1, G2). The unit has an active part (12) inducing, in case of overvoltage, a voltage (U1) at terminals of the gap (G1), in absolute value, greater than a voltage (U2) at terminals of the gap (G2) so that an electric arc is formed initially in the gap (G1).