Changes

for medium and high voltage switchgear.

Resistance welding is the process of electrically joining work pieces by creating

the required welding energy through current flow directly through the

of otherwise difficult material combinations.

During vertical wire welding the contact material is vertically fed in wire form

through a clamp which at the same time acts as one of the weld electrodes

Fig. 3.9: Vertical wire welding (schematic)

During horizontal welding the wire or profile contact material is fed at a shallow

angle to the carrier strip material ''(Fig. 3.10)''. The cut-off from the wire or profile

Fig. 3.10: Horizontal profile cut-off welding (schematic)

Contact tips or formed contact parts produced by processes as described in

chapter 3.1.2 are mainly attached by tip welding to their respective contact

feeding mechanisms.

This process of high current arc discharge welding required the contact material

and carrier to have two flat surfaces with one having a protruding nib. This nib

Fig. 3.11: Percussion welding (schematic)

This contact attachment process is also one of the liquid phase welding

methods. Solid phase lasers are predominantly used for welding and brazing.

spots at the same time.

In high voltage switchgear the contact parts are exposed to high mechanical

and thermal stresses. This requires mechanically strong and 100%

used to solve this problem.

The electron beam welding is a joining process which has shown its suitability

for high voltage contact assemblies. A sharply focused electron beam has

to CuCrZr carriers.

The cast-on of liquid copper to pre-fabricated W/Cu contact parts is performed

in special casting molds. This results in a seamless joint between the W/Cu and