Electric switch device with separable contacts including fixed contact mounted current limiter and shunt conductor

#Field of the Invention

#The present invention concerns an electric switch device comprising separable contacts respectively disposed on a fixed contact conductive part and a mobile contact conductive part which are connected to input and output terminals of the device, an arc extinguishing chamber and a shunt conductor adapted to receive, after it has jumped a dielectric gap, one end of the arc generated on separation of the contacts and displaced towards the arc extinguishing chamber by the usual blast arrangements or phenomena.

#Description of the Prior Art

#FIG. 1 is a diagram showing an arc extinguishing area of a switch device of the invention with the contacts shown closed.

#FIG. 2 shows the contacts of the device during opening.

#FIG. 3 is a diagram showing the contact area of a double-contact switch device.

#The electromechanical switch device shown in FIG. 1 is a contactor or a circuit-breaker including in a casing 10 a current feed conductive part or fixed contact 11 and a current feed conductive part or mobile contact 12 respectively carrying a fixed contact 11a and a mobile contact 12a. The contacts 11a, 12a can be separated by raising the part 12 in a direction A perpendicular to the planes P--P', Q--Q' of the portions of the parts 11, 12 near the contact area. The mobile and fixed parts 12, 11 are respectively current inlet and outlet conductors--or vice versa--and are connected to input and output terminals 13, 14 of the device.

#An arc extinguishing chamber 15, optionally provided with arc splitter plates 16, is provided in the casing 10 at a distance from the contact area in the direction A and in the perpendicular direction B (parallel to P--P' and Q--Q'). The mobile contact part 12 is coupled to an opening and closing device 17 comprising the moving armature of a solenoid 17a and/or a tripping mechanism 17b and/or a manual operating member 17c. Beyond the contact 12a the mobile part 12 has an arc horn 18 in the form of an upstand having a plane or substantially plane outside surface 18a parallel to the direction A.

#An interim arc device 20 is associated with the fixed contact part 11 near the contact area, between the latter and the arc extinguishing chamber 15. The device 20 can instead be associated with the mobile contact part 12, although this is less advantageous. In the present embodiment of the invention the interim arc device 20 is L-shape with, facing the outside surface 18a of the mobile arc horn 18, a switching branch 21 with an arc receiving side 21a parallel to the surface 18a and, facing a plane portion 11c of the part 11 parallel to P--P', a connection branch 22 connected to the fixed contact part 11 by means of a connection area 22a. The end 11b of the part 11 which carries the fixed contact 11a is beyond the connection part 11c. The connection branch 22 is on the opposite side of the contact to the branch 21, parallel to the plane P--P'. The branches 21 and 22 are therefore perpendicular.