US 3126464 A
Description (OCR text may contain errors)
March 24, 1964 ,H STETTNER 3,126,464
I ARC EXTINCUISHING. MEANS Filed June 12, 1961 l'm/enor'.'
Il" a" i7 I @my United States Patent O 3,126,464 ARC EXTINGUISHING MEANS Hubert Stettner, Neumunster, Germany, assigner to Llcentia Patent-Verwaltungs-G.m.b.H., Frankfurt am Main, Germany Filed June 12, 1961, Ser. No. 116,313 Claims priority, application Germany June 16, 1960 8 Claims. (Cl. 200--144) The present invention relates to arc extinguishing means.
There exist alternating current switches equipped with arc extinguishing or arc quenching chambers in which a plurality of electrically conductive partitions or bailles, generally made of ferromagnetic material, are arranged transversely to the moving arc which is formed upon opening of the contacts. When the arc enters the gaps or arc chutes formed by these bailles, the arc is broken up into a series of short, serially-connected partial arcs, whereby the arc extinguishing chamber will be rapidly deionized when the current goes through zero and the re-ignition of the arc, after its natural extinction during its passage through zero, is prevented.
An arc which is moved under the influence of a greater or lesser magnetic ileld, generated by a blowout coil of a type well known in the art, has the tendency, under heavy load conditions, to llash out of the arc extinguishing chamber. This is undesirable, partly because this renders the arc extinguishing bailles ineifective, and partly because this may cause ilashover between phases.
The effectiveness of such arc extinguishing means depends on the number of bailles and the manner in which they are arranged. If the bailles are spaced very near to each other, this will be favorable insofar as the deionization of the arc extinguishing chambers is concerned, and inasmuch as in narrow gaps the arc has the tendency not to develop very high speed, a baille arrangement wherein the individual bailles are spaced closely together will prevent the arc from leaving the arc extinguishing chamber, thereby producing an effective arc extinguishing action. The difficulty, however, is that the arc will tend not even to enter such an arc extinguishing baille arrangement, but to come to a standstill just outside of it, the reason for this being that the arc will not be able to form the number of base points which will correspond to the large number of balles incorporated in an arc extinguishing arrangement wherein the individual bailles are spaced closely together.
It is true that if the individual bailles are spaced further apart, the arc will enter the baille system, but it will then have the tendency to run through the system very rapidly and to ilash out at the other end. Furthermore, relatively long partial arcs will be formed and this means long deionization periods.
It is, therefore, an object of the present invention to provide an arc extinguishing arrangement which overcomes the above disadvantages, and, with this object in view, the present invention resides basically in arc extinguishing chamber means adapted for use with an electric switch having contact means upon the opening of which an arc is formed, which arc extinguishing chamber means comprise a plurality of arc extinguishing bailles arranged transversely to the arc to be extinguished. The arrangement is such that sets of two consecutive spaced-apart bailles are electrically connected together at but one end to form a bame pair with the two bailles of each pair being of different lengths and having opposite free ends directed towards the contact means such that the free ends of the two bailles of each baille pair are spaced diiferent distances from the place whereat the arc to be extinguished is formed.
As a result, the bailles which the arc reaches first are ICC spaced relatively far apart. Consequently, the entry of the arc into the baille system is facilitated. As the arc continues to move into the arc extinguishing chamber, it reaches the shorter bailles which extend less far into the arc extinguishing chamber. As soon as the arc reaches these shorter bailles, parts of the arc are short-circuited by the shorter bailles, which are electrically connected with the longer bailles, so that the arc will assume, a total length equal to Vone-half of its previous length. The number of base points of the arc remains the same. Consequently, the energy of the arc and therefore the deionization time is reduced, and the following advantageous results are obtained: (l) the tendency of the arc to run through the chamber is now reduced due to the fact that it now moves between bailles which are closer together; (2) the hot gases of the short-circuited partial arc can already be partly deionized in the arc chute between the electrically connected bailles of each baille pair; and (3) an electrodynamic counter blowing eifect is obtained which prevents the arc from ilashing out of the chamber, this electrodynamic counter blowing being due to the current loops formed in the two bailles of each baille pair since these two bailles are connected together at the ends thereof which are directed away from the arc.
It will be appreciated from the above that the arc extinguishing chamber means according to the present invention combines the advantages of an arc extinguishing chamber incorporating closely spaced-together bailles with the advantages of an arc extinguishing chamber incorporating bailles which are spaced relatively far apart, without possessing the drawbacks of either of the two heretofore known types of arc extinguishing chambers.
Additional objects and advantages of the present invention will become apparent upon consideration of the following description when taken in conjunction with the accompanying drawings in which:
FIGURE l is a sectional view of one embodiment of an arc extinguishing chamber according to the present invention.
FIGURE 2 is atop plan view of the arrangement shown in FIGURE 1, as seen in the direction of the arrow A.
FIGURE 2a is a diagrammatic view similar to FIG- URE 1 and shows the behavior of an arc entering the baille arrangement.
FIGURE 3 is a sectional view of another embodiment of an arc extinguishing chamber according to the present invention.
FIGURE 4 is a schematic illustration of the baille arrangement according to yet another embodiment of the present invention.
Referring now to the drawings and to FIGURES 1 and 2 thereof in particular, the same show an electric switch, such as a protective or overload circuit breaker, in combination with an arc extinguishing chamber according to the present invention. The switch comprises a movable contact bridge I which cooperates with two stationary contacts 2 which are aligned one behind the other as seen in FIGURE l so that only one of the two stationary contacts is illustrated. Each stationary contact is formed with an elongated portion 3 which serves as a contact surface along which will run the arc which is formed upon the opening of the contact means 1, 2. The arc extinguishing means comprise a housing 4 made of insulating material, and a plurality of substantially parallel bailles. Each two consecutive bailles 6 and 6a are electrically connected together at their ends facing away from the contact means 1, 2, by a suitable electrical connection, as, for example, a transverse web 5, so that each set of bailles 6, 6a, will form a baille pair of which one baille, namely, the baille 6a, is shorter than the other, namely, baille 6. Consequently, an arc formed upon the opening of the contact means 1, 2, will readily move into the baille system and the formation of base points will likewise be facilitated. The magnetic blowout coil which causes this movement is of conventional structure and therefore not shown.
If desired, the web 5 can tightly close the gap between the baffles 6, 6a, of each baille pair. Alternatively, the web may be formed with a cut-out or opening 7 therethrough, or be otherwise perforated.
When an arc is formed upon separation of the switch contacts, the following will happen, as is now explained With reference to FIGURE 2a:
When the arc is driven from condition a to condition b by the main blowing eilect at the contacts with their opposite current paths, a counter blowing eiiect, acting in the direction of arrow B, will set in. This counter blowing, however, is relatively weak and, coupled with the fact that the baille portions will now be closer together, will act mainly to reduce the movability of the arc. Should, however, the arc b move back, the arc between the bailles 6 and 6a will become longer, as shown at c. There will be no re-strike to cause the arc to assume the position a because the arc path b is still highly ionized (this being due to the fact that the bailles are still warm and are spaced closely together) while the path indicated at a will have but small ionization left (the bailles being already cooled and being spaced further apart). As a result, if there should be any re-strike at all, this will occur as indicated by the ilash arrow in FIGURE 2a. In the event of such a re-strike from b to a, the magnetic counter blowing would immediately cease, there being no current loop 6a-b-6. The main magnetic blowing will therefore drive the arc back to the short baille 6a. It is therefore utterly impossible for there to be a re-strike between the contacts.
The embodiment shown in FIGURE 3 differs Vfrom the above-described one in that the bailles 16, 16a,lof each baille pair are arranged in planes forming an angle with each other, with all baille pairs being so positioned that the bailles are arranged in a sector about the place whereat the arc to be extinguished is formed. FIGURE 3 also shows the arc in two stages of its propagation. In stage 8, the arc has just reached the free ends of the longer bailles 16 and has formed base points thereon. In stage 9, the arc has already travelled through part of the narrow gaps 1i) formed between the long baille 16 of one baille pair and the short baille 16a of the adjacent pair, as wellV as through the narrow gap 10a formed between the elongated portion 3 and the long baille 16 of the nearest baille pair. The relatively wide gap-like spaces 11 between the two electrically connected bailles 16, 16a, of each baille pair serve to deionize the hot gases caused by the short-circuited partial arcs. As explained above, the electro-dynamic counter blowing eilect, acting in the direction of the arrow B, cooperates with the other structure to prevent the arc from flashing out of the arc extinguishing chamber.
The above-mentioned narrow and wide gaps 10 and 11 are also indicated in FIGURE l.
FIGURE 4 shows an arrangement in which the baille system includes not only a plurality of baille pairs each 4 constituted by a long baille 26 and a short baille 26a connected together by a transverse web 25, but also individual bales 12 which are not connected to any other baille.
It will be seen from the above that, according to the present invention, there, where the arc enters the baille arrangement, the bailles are spaced further apart than there, to whence the arc moves upon propagation into the baille arrangement.
It will be understood that the above description of the present invention is susceptible to various modifications, changes, and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of theappended claims.
What is claimed is:
' l. A circuit breaker comprising, in combination: an electric switch having contact means upon the opening of which an arc is formed; and means forming an arc extinguishing chamber and comprising a plurality of arc extinguishing bailles arranged transversely to the arc to be extinguished, sets of two consecutive spaced-apart bailles being electrically connected together at but one end to form a baille pair with the two bailles of each pair being of diilerent lengths and having their opposite free ends directed toward the contact means such that the free ends of the two bafiles of each baille pair are spaced diilerent distances from the place whereat the arc to be extinguished is formed in consequence of which there, where the arc enters the baille arrangement, said bailles are spaced further apart than there, to whence the arc moves upon .propagation into the baille arrangement.
2. A circuit breaker as deilned in claim 1 wherein the two bailles of each baille pair are connected by a transverse web.
3. A circuit breaker as defined in claim 2 wherein said web closes toward the outside thereof the space between the two respective bailles.
4. A circuit breaker as deilned in claim 3 wherein said web is formed with an opening therethrough.
5. A circuit breaker as deilned in claim 3 wherein said web is perforated.
6. A circuit breaker as defined in claim 1, further comprising additional bailles electrically disconnected from any other baille.
7. A circuit breaker as deilned in claim 1 wherein the two bailles of each pair are arranged substantially parallel to each other.
8. A circuit breaker as deilned in claim l wherein the two bailles of each pair are arranged in planes forming an angle with each other.
References Cited in the ile of this patent UNITED STATES PATENTS