HK1095425B - Electric switching device comprising an arc-quenching unit - Google Patents

Description

Electrical switching device with a device for extinguishing arcs

Technical Field

The invention relates to an electrical switching device designed for low voltages, having at least one device for extinguishing arcs, in particular to a protective switch or contactor.

Background

When a high current, in particular a short-circuit current, is switched off by the switching device, an arc is formed in its switching chamber. Arc lengthening, arc cooling and arc dividing are disclosed as methods for extinguishing arcs in air according to "niederswanns-leistringsschalter" by Franken, berlin, heidelberg, new york, 1979, pages 59 to 62. In the case of arc cooling, intensive cooling of the arc is essentially achieved by contact with an insulating material piece or a cooling plate. In the case of arc division, the arc is driven by magnetic force into a system of parallel or arc-shaped extinguishing plates and divided into a plurality of partial arcs, which leads to a significant increase in the voltage losses within the entire arc. The cooling plate can be produced more simply and thus more cost-effectively than the arc plates, but is slightly inferior in terms of the magnitude of the arc current to be extinguished.

DE 4109717C1 describes a contactor having: the electromagnetic actuator is arranged in a multi-part housing, the switching contacts are arranged in a switching chamber and the quenching plates are assigned to the switching contacts and form an arc extinguishing chamber, which are mounted in a housing part that can be closed by a cover. The arc plates, which are assembled by insulating plates into arc plate groups and are inserted into the housing chamber, are pressed and held elastically against the wall of the upper housing part by the terminal legs of the commutator bars, which are bent into a U-shape in a double manner.

In the case of the contact device according to DE 19814411C1, the arc plates which are uppermost toward the cover and which are designed as shielding plates each have two webs which are bent upward. The slot chambers associated with these tabs are configured on the inside of the cover. The arc chute can be fixed to the cover by inserting the tab into the slot space, forming a form-locking connection.

Disclosure of Invention

The object of the invention is to make it possible to use a switching device with a simple switching device for different current ranges.

According to the invention, an electrical switching device with a device for extinguishing an arc is proposed, wherein connection contacts accessible from the outside are fixed in a housing which can be closed by a cover, in which housing switching chambers are formed, in each of which switching chambers a fixed switching contact, a movable switching contact interacting with the switching contact and at least one arc extinguishing device in the form of a cooling plate or an arc quenching plate group are provided, wherein: in the housing and in the cover, guides and holders are formed for the insertable cooling plates and for the groups of arc quenching plates that can be interchanged with these cooling plates.

The object of the invention is achieved by the above-described solution on the basis of a switching device of the type mentioned at the beginning, while advantageous further developments of the invention are obtained from the following description.

The housing and the cover are equipped with guides and holders for not only the cooling plates but also for groups of arc extinguishing plates. This makes it possible to optionally equip switching devices which are otherwise of the same design with arc extinguishing devices in the form of cooling plates or arc extinguishing devices in the form of groups of arc extinguishing plates. In the case of the installation of cooling plates, more cost-effective variants of the switching device result, while in the case of the installation of arc quenching plates variants of the switching device with higher switching capacity result. The individual required switching device configurations can thus be produced at low cost and with the remaining of further components.

An advantageous embodiment of the invention provides that the quenching plates are held in a guided manner by the inner wall of the housing and the shaping and the pressed first holding element of the cover. Another embodiment provides that the arc chute group is fixed by a second holder of the cover. One advantageous configuration is that the guide and holder for the cooling plates and the guide and holder for the arc chute group are arranged one after the other, with the guide and holder for the cooling plates being closer to the switching contacts and the guide and holder for the arc chute group being closer to the connection contacts.

Drawings

Further details and advantages of the invention can be taken from the following exemplary embodiments, which are illustrated with the aid of the figures. The attached drawings show that:

FIG. 1: a housing of a switching device according to the invention with an arc quenching device, shown in a perspective exploded view;

FIG. 2: a top view of an open housing with an embedded cold plate;

FIG. 3: longitudinal section III-III with attached lid according to fig. 2;

FIG. 4: a plan view of an open housing with an interposed arc chute group;

FIG. 5: longitudinal section V-V with attached lid according to fig. 4.

Detailed Description

Fig. 1 shows the upper part of a multi-part housing 2 of an electrical switching device, for example a three-pole contact, and a two-part cover 4 which closes the housing 2. Two contact rails 6 with externally accessible connecting contacts 8 are arranged in the housing 2 for each pole. The contact rails 6 project into switching chambers 10, which are laterally delimited by inner walls 12 formed in the housing 2. On the switching chamber side, the contact rail 6 is provided with fixed switching contacts 14 which interact in a known manner with movable switching contacts in the form of contact bridges which are not shown. An arc quenching device in the form of either a U-shaped cooling plate 16 or an arc quenching plate group 18 of arc quenching plates 20 arranged one above the other at a distance from each other can be inserted into each switching chamber 10. For this purpose, guide and retaining elements, which are described in more detail below, are formed in the housing 2 and in the cover 4. In each switching chamber 10, the installation position of the cooling plate 16 and the installation position of the quenching packet 18 extend in succession in relation to the longitudinal direction of the associated switching pole. In this case, the cooling plate 16 is mounted closer to the fixed switching contact 14, while the quenching packet 18 is mounted closer to the connection contact 8.

According to fig. 2 and 3, the cooling plate 16 is guided with its outer leg 22 laterally by the inner wall 12 and is positioned with its end face 24 facing away from the cover 4 in a correct position in a groove-like shaping 26 on the bottom 27 of the housing part shown in the housing 2. First holding elements 28 are formed on the inner side of the cover 4, which hold the cooling plate 16 in place and lock it in its installed position when the cover 4 is closed.

According to fig. 4 and 5, the arc plate group 18 can be fixed in a second cavity-like holder 30 of the cover 4 with a lateral force fit (kraftschlussig) and/or form fit (formschlussig). When the cover 4 is covered on the housing 2, the arc plate group 18 will be locked in its mounted position between the inner walls 12 and the bottom 27 of the housing 2 and the cover 4.

Claims (4)

1. Electrical switching device with a device for extinguishing an arc, in which a connection contact (8) accessible from the outside is fixed in a housing (2) which can be closed by a cover (4), in which housing switching chambers (10) are formed, in each switching chamber (10) a fixed switching contact (14), a movable switching contact interacting with the switching contact and at least one arc extinguishing device in the form of a cooling plate (16) or an arc quenching packet (18) being provided, characterized in that: guide and retaining elements (12, 26, 28, 30) are formed in the housing (2) and in the cover (4) for insertable cooling plates (16) and for an arc quenching packet (18) that can be interchanged with these cooling plates.

2. An electrical switching apparatus according to claim 1 wherein: the cooling plates (16) which are designed in a U-shape are supported with their outer leg edges (22) on the inner wall (12) of the housing (2) which laterally delimits the switching chamber (10) and with their end faces (24) facing away from the cover (4) in a groove-shaped profile (26) of the housing (2), said plates being pressed against a first holding part (28) of the attached cover (4).

3. An electric switching device according to claim 1 or 2, characterized in that: the arc plate groups (18) can be fixed by one side in a second, force-and form-locking, cavity-shaped holder (30) of the cover (4) and are supported between the inner walls (12) of the housing (2) that laterally delimit the switching chambers (10) when the cover (4) is mounted.

4. An electric switching device according to claim 1 or 2, characterized in that: the guide and holding elements (12, 30) for the arc quenching packet (18) are connected to the guide and holding elements (26, 28) for the cooling plate (16) in the direction of the connection contacts (8).