DE2362089A1 - Electric arc quenching plate for switches - having ferromagnetic core plated with material increasing re-setting voltage - Google Patents

Abstract

Quenching plate with suction effect on the electric arc for the quenching equipment of switches has a core plate of ferromagnetic material (I) plated, at least on 1 and pref. on 2, 3 or 4 sides, in a thickness of at least 0.1mm, with materials (II) with boiling, sublimation or decompsn. temp. at least 10% below that of (I) and/or electric conductivity at least 10% above that of (I). Pref. (II) is brass, Zn, Mg, Cd, Ag-CdO, Ag-ZnO, Cu-CdO, Cu-ZnO, Wood's metal, Ag, Cu, Au or Pt metals and (I) is Fe or Fe alloy. In particular, the plate consists of brass-plated sheet Fe or steel. Over a section of the plate about half consists of (I) and half of (II). The plate combines the advantages of (I) w.r.t. the arc effect with those of (II), which increase the re-setting voltage.

Description

GERMAN GOLD AND SILVER SCHEIDEANSTALT FORMERLY ROESSLER 6-Frankfurt am Main, Weissfrauenstrasse 9

Extinguishing plates for electrical switches

The invention relates to quenching plates for electrical switching devices those of the arcing that occurs when switching off in one several extinguishing plates existing extinguishing plate pack to extinguish is brought.

It is known that in switchgear for low and high voltage, the arc that occurs when switching off is conducted into an extinguishing system consisting of arc extinguishers, whereby it can be wholly or partially divided into several series arcs that hold on to the extinguishing arc. In addition to cooling through the metal sheets, AC switching devices are extinguished by physical processes that take place at the cathodic base points after the polarity change. After the polarity change, these cathode regions can absorb a certain voltage, referred to as the resolidification voltage, before an arc reignition occurs. It is also known from scientific studies that the resolidification stress increases with decreasing base point temperature and that materials with a lower boiling, sublimation or decomposition temperature generally cause a higher resolidification stress. From systematic studies it has become known that \. that the breaking capacity increases with the reconsolidation voltage and that the reconsolidation voltage and thus the breaking capacity increases with the number of partial arcs connected in series. _:

- - - - \ ■ - "' Extinguishing plates of known switchgear consist-usually of

Copper, brass, aluminum, iron or iron alloys.

The advantage of ferromagnetic extinguishing sheet materials, e.g. sheet steel,

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is that due to the ferromagnetic distortion of the magnetic The arc's own field, a force is exerted on the arc that tries to pull it into the arc splitter, This sucking force makes it possible to create magnetic blown field devices, which are usually made by appropriate design of the Power supply lines to the arc extinguishing device are established, to be dimensioned weaker or to be omitted entirely. Another advantage of the well-known quenching plates made of ferroraagnetic Material is that on the arc, which once in the arc splitter assembly has been drawn into it and divided, a force is exerted that is equivalent to that caused by current loops in the arc splitter assembly caused tendency to leave the sheets again, counteracts. The disadvantage of ferromagnetic materials is it but that their selection is determined by the magnetic properties while other known materials would be much cheaper from the point of view of resolidification.

In contrast, materials with a low boiling, sublimation or decomposition temperature have better resolidification properties •on. However, they lack the ferromagnetic properties and thus the tendency to tighten and hold onto the arc or its parts, which can only be achieved through considerable additional effort can be compensated for in the structural design of the entire extinguishing system.

Switching devices have also been manufactured with their steel quenching plates for optical or corrosion protection reasons with thin, mostly galvanically applied coatings of silver, copper, zinc, Cadmium or tin.

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Since these, only a few μπι thick coatings by the arc however, after a few switching operations, they are destroyed and worn away, such quenching plates have no special effects in relation to them on increasing or decreasing the breaking capacity the dimensions with the same breaking capacity.

In some known switchgear constructions, the Current loops in the arc splitter assembly caused force which tries to drive the arc out of the arc stack, thereby reduced or made ineffective that by folding the quenching plates or a part of them, the cross-section of an elongated U or an elongated closed 0 form. The current flow in the quenching plates, which is predetermined by these shapes, generates magnetic fields that tend to leave the Quenching plates,

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counteract. This improves the deletion. Is disadvantageous This is the complex compared to simple, stamped sheet metal Manufacturing process, Since the two legs must not touch, must for insulating material interlayers or mechanically strong Restraint must be taken care of. In the case of an O-shaped cross-section, the sheets are also soldered or smoldered.

It was therefore an object of the present invention to provide quenching plates for to develop electrical switching devices that have the advantageous properties of ferromagnetic materials in relation to the effects of arcing unite with those of those materials that increase resolidification stress.

According to the invention, this object was achieved in that a Core sheet made of a ferromagnetic material at least on one side is clad to a thickness of at least 0.1 mm with such materials, their boiling, sublimation or decomposition temperature at least $ 10 below that of the core sheet material and / or their electrical conductivity by at least 10 ^ over the conductivity of the core sheet material.

The disadvantages of the known quenching plates are in the inventive thereby avoiding that each quenching plate, from a ferromagnetic Core sheet consists on which a metallic material is clad, the properties of which are exclusively based on it is tuned to improve arc extinction without affecting ferromagnetic properties must be taken into account. This makes the advantageous suction, i.e. the arc attractive effect of ferromagnetic quenching sheets combined with the the extinguishing-improving effect of other special materials, so that an increase in the breaking capacity without further ado Enlargement of the extinguishing system is possible.

By using clad materials, it is possible to create conditions to manufacture any thickness from materials selected only from the point of view of improving the extinction

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can be. In the immersion process or in electrolysis can be either alloys or multi-component composites such as metal / metal oxide materials cannot be applied at all or only in very limited compositions with great difficulty. In addition, they are with it achievable layer thicknesses only so small that a dimensioning of the Thickness of the coating for the entire life of the switchgear is not possible. -. . .

Particularly advantageous in terms of breaking capacity, extinguishing effect and service life are extinguishing plates that are seen across the cross-section consist of half core material and half of the cladding layer, regardless of whether it is clad on one, two, three, four or all sides are. .

In a preferred form of the quenching plates according to the invention is the ferromagnetic core sheet, which is preferably made of iron or an iron compound, with material on both sides Plated at a low boiling, volatilization or decomposition temperature. As such materials that have a high resolidification stress own, lcöanen brass, zinc, cadmium, magnesium and composites such as silver / cadmium oxide, copper / cadmium oxide, silver / zinc oxide, Copper / zinc oxide are used, especially proven as a cladding material have brass and the listed composites. The quenching plates are expediently made of clad semi-finished products. punched out in the form of sheets or strips by conventional methods. '"-:" -.

The quenching sheets can also consist of the core sheet and a three-sided Plating according to Figure II or a four-sided Plating according to Figure III made of good electrical conductivity Material. The cross-section of the highly conductive material. corresponds to an elongated U in the case of three-sided cladding, and to an elongated U in the case of four-sided cladding

Since the flow of current takes place mainly in the highly conductive coating material, the same becomes the one that improves the erasure

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This effect is achieved as with the well-known U- and 0-shaped folded extinguishing plate designs. With these quenching plates according to the invention, there are no operations that were previously additionally required for folded plates and, moreover, the space requirement per quenching plate is lower. Examples of highly conductive materials are silver, copper, gold, platinum metals and their alloys. In the case of four-sided cladding, such quenching plates are expediently produced by simply cutting off four-sided clad strips. Sheets clad on three sides can also be produced by cutting strips clad on three sides or by punching them out in pairs from strips clad on four sides.

Figure I gives an example in a schematic sectional illustration Embodiment of the quenching plate according to the invention again.

The ferromagnetic core sheet 1 is two-sided with plated editions 2 made of materials with low boiling sublimation or decomposition temperature Mistake.

Figure H shows schematically in cross section a further embodiment of a quenching plate according to the invention, the core plate 3 being provided with a three-sided cladding W made of a material with good electrical conductivity.

Figure M. shows, in cross section, an embodiment of a quenching plate according to the invention, consisting of a core plate 5 with four-sided plating 6 made of a highly conductive material.

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Claims (1)

Claims Arc quenchers with a suction effect for. Extinguishing arrangements of switching devices, characterized in that a core sheet made of ferromagnetic material is clad at least / on one side with a thickness of at least 0.1 m with materials whose boiling, sublimation or decomposition temperature is at least 10 $ below that of the core sheet material and / or whose electrical conductivity is at least 10 $ higher than the conductivity of the core sheet material. 2. quenching plates according to claim 1, characterized in that the core sheet is plated on two, three or four sides. ■ 3. quenching plates according to claim 1 and 2, dadurc'h- gekeniizeichnet , that for plating as a material with a low boiling point etc. brass, zinc, magnesium, cadmium, Wood's metal, Silver-cadmium oxide, silver-zinc oxide, copper-cadmium oxide or Copper-zinc oxide and, as highly conductive materials, silver, copper, Gold or platinum metals can be used. 4. quenching plates according to claim 1 to 3 *, characterized in that iron or iron alloys are used as ferromagnetic materials. 5 extinguishing plates according to claims 1 to k, characterized in that they consist of iron or steel plates plated with brass, 6. quenching plates according to claim 1 to 5 » characterized in that, viewed across the cross-section, they each consist approximately half of core material and cladding layer. 12/13/1973
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