OVERVOLTAGE PROTECTOR FOR A DEVICE HAVING TWO PARTS MOVABLE RELATIVELY TO EACH OTHER

摘要

The invention relates to an overvoltage protector in an apparatus having two moving parts. The parts are in mutual communication via a bearing, one part being stationary in relation to a substructure at ground potential. The moving part can be subject to a voltage and the stationary part is electrically connected to the earthed subsubstructure. For preventing a current passing through the bearing between the parts, an electrical insulator is provided in the current path through the bearing. The moving part has a projection at a distance from an electrode connected to ground such that a spark discharge gap is formed between mutually moving parts. The bearings are protected against current by the electrical insulator up to a given voltage threshold. In order that this voltage threshold will not be exceeded, the spark discharge gap comes into operation at a lower value than this voltage threshold and keeps the voltage difference between the parts at this lower value.