Tungsten Copper Arc Contact

Tungsten-Copper-bar    
Tungsten copper alloy (WCu) is used for arcing contacts in SF6 circuit breakers for ultra high, high and medium voltage applications. At the heart of the switching chamber, WCu contacts are exposed to extreme mechanical and thermal loads: When the circuit is opened and closed, the arc starts directly at the switch contacts at a temperature of up to 20 000 °C.
Tungsten Copper Alloy

Tungsten copper alloy is popular because of its combination of unique material properties. A high level of temperature resistance is one of the most important advantages of tungsten, while the copper content increases the electrical and thermal conductivity. Contact materials made of WCu are also characterized by the following properties:

High arc eros
ion resistance
Good electrical conductivity
Excellent strength
Very good machinability
Good thermal conductivit
Low thermal expansion

No arc erosion: With the right mix of materials.
tungsten-copper    
By choosing the right mixture of tungsten and copper, we are able to influence the product's arc erosion properties. At a tungsten content of 80 %, we achieve the lowest arc erosion rates. Depending on the voltage and current intensity as well as on economic considerations, we can vary the tungsten content between 60 and 90 % to meet the exact needs of clients' application.

Good conductivity: High density makes it possible.
The denser the material, the better it is at conducting electricity and heat. One trick for producing WCu in higher densities is to add nickel during the sintering process. However, too much nickel has a negative influence on the conductivity of the material.