Overvoltage protective device for use in low-voltage mains power supply, has arc combustion chamber formed between one electrode and another electrode, and insulation section connected in series with arc combustion chamber

摘要

The device (1) has an arc combustion chamber (4) formed between an electrode (2) and another electrode (3), and a partially-conductive granulate material arranged within the combustion chamber. An insulation section is connected in series with the chamber. A third electrode (7) is arranged at a distance to the former electrode in such a manner that the third electrode together with the former electrode form another combustion chamber (8) with a drift-spark gap (9) as the insulation section, where an arc is developed between the former and the latter electrodes during ignition of gap. The partially-conductive granulate material consists of a conductive ceramic material. The device comprises an isolating granulate material e.g. porous ceramic or mineral material. The electrodes are made from a combustion-resistant non-metallic, electrically conductive material e.g. conductive ceramics.