The invention relates to an electrical terminal connection for the electrodes of a gas discharge over or surge voltage arrester with the following features:
(a) the electrodes to be connected consist of a material with good current conductivity;
(b) the connection should respectively occur at a wire consisting of a material with good current conductivity.
Efficient over-voltage arresters must be able to arrest surge currents&gt;10 kA. In dual-path over-voltage arresters, this meas that a sum current&gt;20 kA flows across a common center electrode. Given electrical terminal connections via resiliently contacting contacts, such high surge currents cause sputtering of the contact material and thereby damage the sockets. Terminal wires which are soldered in and which generally consist of copper and then exhibit a diameter of approximately 1 mm offer a better electrical terminal connection for such currents. Copper is likewise preferably selected as the electrode material for electrical and economic reasons. The rigid connection between the electrode and the terminal wire can then be produced by means of soldering or welding.
Both are proposed, for example, in German OS No. 28 28 650, incorporated herein by reference. On the one hand, the possibility is there described of soldering a tubular rivet to the floor of the cup-shaped electrode and then squeezing (FIG. 4) the terminal wire in the tubular rivet. On the other hand, a welded connection is provided to "press" a cylinder to the floor of the cup-shaped electrode, the diameter of said cylinder being approximately 1.5 times as great as the diameter of the terminal wire. The terminal wire is welded blunt to said cylinder. Said cylinder has the object of reducing the thermal dissipation during the welding operation. Welding to the smooth bottom of the electrode or, respectively, to the jacket surface of a center electrode would not be possible given material which has high current conductivity and, thus also has high thermal conductivity.
Even given a cylinder dimensioned in such manner, however, a welded connection is only possible as a short-time welding, for instance as pulsed resistance welding. Particularly given a connection of copper to copper, this, however produces unreliable connections.