DE1030422B - Electrical switchgear, in particular air protection - Google Patents

Description

GERMAN

It is known in electrical switching devices to cut out the fixed contact pieces below the contact surface, thereby forming a loop as narrow as possible for the current flow, which favors the running of the arc base. The arc quenching in switching devices with such contact pieces can be significantly improved, with the contact pieces being protected at the same time if the contact piece support is provided with an extension in the direction of the arc path. This extension is expediently made from an iron sheet, which is connected to the contact piece or the contact piece support by brazing. In order to fully exploit the effect sought by the recess of the contact piece, it is expedient to largely constrict the contact pieces in the groove resulting from the recess. But this gives the contact more or less resilient properties _; which can sometimes lead to bouncing of the contacts.

This disadvantage is in electrical switching devices, especially air contactors, with below the Contact surface recessed fixed contact pieces and in the direction of the arc path over the contact piece also extended contact piece support, in particular consisting of sheet iron eliminates that, according to the invention, the extension of the contact piece support is supported at its free end is. For this purpose it can, for example, be attached to the connecting rail of the contact piece will. But because of a conductive connection with the connecting rail, the arc base If the driving loop effect is lost, this fastening is carried out with an intermediate layer of insulation.

To explain the invention, the drawing shows an exemplary embodiment of such a contact piece shown.

Fig. 1 shows the side view,

Fig. 2 is a section along line AB.

On the connecting rail 1, the switching piece 2 is attached, which is cut out in a known manner at 3, to create a loop driving the arcs. As can be seen, the contact piece is at the corner largely constricted at 4.

Following the contact piece support 5, an extension 6 made of sheet iron is provided which extends in the direction of the arc path. This extension is attached to the connection rail 1 according to the invention by a bolt 7, while avoiding a conductive connection between the extension 6 and the connection rail ¹ 1 by the interposition of Isolierstoffscheiben. 8

By extending the contact surface, the accessibility of the fastening screws of the electrical switchgear,
especially air contactor

Applicant:

Siemens-Schuckertwerke

Corporation,

Berlin and Erlangen,

Erlangen, Wemer-von-Siemens-Str. 50

Dipl.-Ing. Gustav-Wilhelm Pristsak, Berlin-Spandau, and Dipl.-Ing. Helmut Stroedter, Berlin-Tegel,

have been named as inventors

difficult for the contact piece. It is therefore advisable to extend the contact piece above the To provide fastening screw for the contact with a hole 9 through which a Tool for loosening or tightening the fastening screw 10 can be passed through. To now this hole to the minimum required to be able to restrict, is preferred for the attachment · of the contact pieces, as in the drawing indicated, a screw with a hexagon socket used.

If the fastening web of the contact piece 2 is possible for reasons of space and material savings is kept thin, there is a risk that the end of the contact on the connecting rail will not get enough rests, but may even gap. This will reduce the tendency of the switch to bounce further favored. In the illustrated embodiment, this tendency is therefore to be avoided the contact piece is pressed on with the aid of a pressure plate 11 placed under the fastening screw 10. This pressure plate has a Z-shaped cross-sectional shape (see FIG. 2), with one side web 11 'as an abutment serves on the mounting foot of the contact and forms a rotation protection, while by the other, upwardly curved web 11 "an increase in the longitudinal rigidity of this pressure plate is achieved. The contact piece itself has a slot on the side

809 527/358

provided so that it is pushed under the pressure plate 11 can be without the fastening screw 10 having to be completely unscrewed. It is recommended that the upwardly withdrawn web 11 ″ of this pressure plate with a to provide wide rounding to facilitate the insertion of the contact piece.

In order to achieve particularly good pressure transmission from the pressure plate to the contact piece, especially on the latter To achieve the front, it can be at the front, its underside be provided with a wart-like elevation.

The invention is particularly important for air contactors for larger currents, but can with other electrical switching devices of all types of application Find.

Claims (2)

Claims ::; " 1. Electrical switching device, in particular air protection, with underneath the contact area spared fixed contact pieces and in the direction of the arc path beyond the contact piece extended, in particular made of sheet iron, contact piece support, characterized in that the extension of the contact piece support is supported at its free end is. " ^{: Ϊ5} Γ 2. Switching device according to claim 1, characterized ge * ¹ indicates that the free end of the extension is insulated and attached to the connecting rail. ^{: i} Documents considered: i German Patent Nos. 929258, 919 722; 512. %: 1 sheet of drawings ..f Jl . © «09527/358 5.58