Siemens Aktiengesellschaft

Joachim Hannich

Heinrich Hassler

Johann Bauer

Werner Harbauer

Joachim Grosse

Heinz Seidenbusch

Gert Fischer

A switchgear apparatus having three switching gaps with contacts arranged thereacross for connecting three-phase electrical power to a consumer. Apparatus is described whereby a selected one of the switching gaps closes earlier than the other switching gaps during a closing cycle of the switchgear, and opens later than the other switching gaps during an opening cycle of the switchgear. The contacts across the early closing and late opening gap experience only minimal contact burnoff, thereby permitting a substantially reduced volume of contact overlay material to be provided therefor. In addition, less expensive contact material may be utilized for this contact.

Three-phase switchgear

Magnetic switch

A method of manufacturing a contact bridge for an electric switching apparatus which contact bridge includes an electrically highly conductive overlay and a concave-shaped support layer. The method comprises the steps of pressing a powder blank comprising two layers of metallic material, one of which comprises iron for the support layer and the other of which comprises copper for the overlay; sintering the blank in a protective gas; sizing the blank; further sintering the blank in a protective gas; further pressing the blank by reverse-flow cup extrusion; and applying an electrical contact to the overlay. Alternatively, the powder blank may comprise a layer of copper-zirconium and silver-metal oxide, the latter for an electrical contact layer. In this embodiment, the contact bridge is formed with the electrical contact in one step and there is no need to apply a contact to the bridge after the pressing by reverse-flow cup extrusion.

Method of manufacturing a contact bridge

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Amberg, Germany

Joachim Hannich