US3178544A

US3178544A - Electric switch with arc extinction in air and with magnetic blasting

Info

Publication number: US3178544A
Application number: US229030A
Authority: US
Inventors: Mayer Albert
Original assignee: BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Germany; BBC Brown Boveri France SA
Priority date: 1961-10-09
Filing date: 1962-10-08
Publication date: 1965-04-13
Anticipated expiration: 1982-04-13
Also published as: DE1151039B; CH391831A

Description

Aprll 13, 1965 A. MAYER 3,178,544

ELECTRIC SWITCH WITH ARC EXTINCTION IN AIR AND WITH MAGNETIC BLASTING Filed oct. s.y 1962 3 Sheets-Sheet 1 6 Ilm 7 Il V FIG! INVENTOR Albert Mager BY l j@ fW-fsf l April 13. 196s A. MAYER 3,178,544 ELECTRIC SWITCH WITH ARC EXTINCTION IN AIR AND WITH MAGNETIC BLASTING Filed Oct. 8, 1962 3 Sheets-Sheet 2 /NVENTQR Alberi; Mayer.

BY @,JWN PWM ATTORNEYS April 13, 1965 A. MAYER ELECTRIC SWITCH WITH ARC EXTINCTION IN AIR AND WITH MAGNETIC BLASTING 3 Sheets-Sheet 3 Filed Oct. 8, 1962 INVENTOR Afber: Mujer BYQ l J 2 z a/MA, ATTORNEYS United States Patent O ELECTRIC SWITCH WITH ARC EXTINCTIN IN AIR AND WITH MAGNETIC BLASTING Albert.Mayer,.Wettingen, Switzerland,.assignor to Aktiengesellschaft Brown, RoveriV & Cie, Baelen, Switzerland,

a joint-stock company Filedy (Ict. 8,1962, Ser. No; 229,030 Claims prioritapplication- Switzerland, Oct. 9, 1961, 11,6 81 /61l 8 Claims. (Cl. Mtl-147) The invention concerns a` circuit breaker withv magnetic blow-out action'w-here the are is blown into several adjoining chambers and by means of auxiliary horns which connect the individual chambers electrically isrotated by about 909, so that the arc together with the auxiliary horns forms a solenoid or electromagnet.

With alternating-current circuitv breakers havingl magnetic blow-out act-ion, the arc` which formsl between the contacts isforce'd byv its own eld or by an additional air blast into the arc extinguishing chambers. Arrangements are known whereby the arcl canbe rotated 90. This is achieved byarranging several arcextinguishing chambers' next to each other which are connected together electrically. by the intermediate horns fixed to the separating walls. The'intermediate horns are given. such a shape that they conductV the roots of the arc sections to the beginning and end'of the chambers. Thus when the cham-A bers themselves lie perpendicular to the original` path of the arc, the latter will be rotated by 90. Inside the chambers the arc rises upwardly due to the magnetic blowout actionV ofthe circuit breaker. The temperature rise which occurs also drives the arc upwards. In this way an arc loop occurs between the roots at the intermediate horns. Suchloops lie in each` chamber next to each other and therefore form` an electromagnet. This electromagnet acts similarly to a. coilk and accelerates the lengthening of the arc until finally it breaks.

In a similar arrangement, metallic plates are provided in the isolating chambers which cause a further subdivision ofthe arc in the individual chambers. In this type of circuit breaker the upward movement of the arc is considerably impeded because it has to form new roots on the metallic plates and thus loses energy. Moreover with such a circuit breaker the shape of the electromagnet is not perfect because the arc burns more or less highly between the individual plates.

In both types of circuit breakers it is necessary to provide additional devices at the upper end in order to prevent the arc from leaving the chamber.

It has therefore been found that it would be expedient to increase the blowing effect of the electromagnet in the lower part of the chamber and to weaken it in the upper part in order to avoid having to provide additional devices to prevent the arc from leaving the chamber.

In order to solve this problem it is now proposed in accordance with the invention to arrange at least one further narrow chamber between the arcing chambers in which at least one turn of a coil is located.

An example of such a circuit breaker is shown in the accompanying drawings wherein FIG. 1 shows an embodiment of a switch according to the invention partly in elevation and partly in a section.

FIG. 2 shows a perspective view of the arrangement according to FIG. l, and;

FIG. 3 is a partial view of FIG. 2, showing additional details.

In FIGS. 1 and 2 the stationary contact member is designated with 1 and the moving contact member with 2. The latter is connected with a drive, which is known in itself and which is not represented here, designates the magnetic blast coil, one end of which is electrically ICC connected with the stationary contact 1, while the other end `is connectedv with the left? main spark horn 3. The

arc extinction chamber above consists of' several sectional" chambers 7 to 11 and 13 to 18, which are formed by insulating walls. In the sectional chambers 7 to 11 are arranged a number of metal laminations 23, which are arranged between the auxiliary horns 12 and 12 respectively, as it can be seen clearly from- FIG'. 2.. The distance between the auxiliary horns 12 and 12V respectively and the adjoining metal laminations- 23' is about the same as between the metal lamination themselves. In each of the sectional chambers 13 to 18' are arranged three turns of a coil 19, the lower end 20 of the center turn of each coil being lower than the lowest point of the auxiliary horns 12 and 12 respectively. The

upper ends

21, 22 of the coil turns are so staggered that the end 22 comes to lie lower than the two-ends 211 In the widest chamber at the left, the rst of the turns is connected with the main spark horn 3, while the thirdy turn is conf neeted with the auxiliary horn 12 in the next chamber 7 (FIG. 2). In a similar manner the auxiliary horn 12 is so set oli" in the chamber 7 that it leads approximately in the-center at the lower end of' the partition between the chambers` 7 and 14 into-the chamber 14 and is con nected therewith the first turn of coil 19 there. The turns of the coils 19 can also be integral with the respective auxiliary horns 12, 12 and` with the main spark horns 5, 4 respectively. The methodA of operation during thedisconnection is such that the movable contact members 2` is turned-clockwise fromt-he closed position, FIG. 2.

FIG. l shows an intermediateposition of the switch contacts after the movable contact member 2 has just' been disengaged from thestationary contact member 1. The arc established between these two contact members due to the load current passing through the switch is caused to first move upward due to the loop effect and thermal lift so that the roots of the arc are transferred to the main spark horns 3, 4. The magnetic blow-out coil 5 is thereby connected into the disconnecting circuit so that a strong magnetic blast field is formed by means of the pole plates 6, which drives the arc additionally upward. The arc arrives at the bottom edges of the auxiliary horns 12, 12 and forms there new roots. In this manner partial arcs are formed between the lower parts of the auxiliary horns 12, 12 in the Various sectional chambers 7 to 11, which rise between the V-shaped auxiliary horns and are rotated by about from the original direction, so that the current path formed from the auxiliary horns 12, 12' and the partial arcs forms a solenoid. The various loops of the solenoid are widened during the rise of the arcs, this widening being enhanced by the fact that the turns of the blast coils 19 in the sectional chambers 13 to 18, which are now connected into the current path, likewise drive the arcs upward by producing a blast iield which extends in the longitudinal direction of the switch.

As soon as the partial arcs have risen in the sectional chambers 7 to 11 so far that they arrive in the region of the metallic laminations 23 arranged between the auxiliary horns 12, 12', the partial arcs are again subdivided into a plurality of small arcs. The latter burn between the auxiliary horns 12, 12 and between the metallic lamination 23. The turns of the blast coils 19 in the sectional chambers 13 to 18 are so designed that they lie partly Patented Apr. 13, 1965 The blast coilv contains a cylindrical with their bottom part 2.@ lower than the lowest point of the auxiliary horns 12, 12', so that a vigorous upward blast sets in at the start already, when the partial arcs have formed at the lower end of the auxiliary horns 12, 12. On the other hand, the

upper ends

21, 22 of the coil turns are staggered lin height. This has the effect, on the one hand, that the partial arcs are slowed down in their velocity while they rise in the sectional chambers 7 to 11 toward the upper end of the metal lamination 23, the highest points 22 of the coil turns representing then the upper limit up to which the arcs are blasted unless they extinguish before.

It has also been found that a phase displacement between the magnetic iield of the blast coil 19 and the disconnecting current enhances the extinction. This phase displacement can be achieved by introducing an iron core between the turns of the coil 19. This iron core is shown in FG. 3. A further improvement in this respect can be achieved by an additional short-circuited secondary winding to the coils 19. In FIG. 3 this secondary short-cir cuited winding is represented as a metallic strip 25, for example, of copper which encloses the iron core 24 along its narrow sides.

With the arrangement according to the invention, not only is the blow-out eect increased so that the arc can be extinguished more quickly and a better blow-out action is achieved in the upper part of the chamber, but it is also possible to provide much simpler plates for dividing the arc inside the chamber. It has already been proposed to make these plates partly out of magnetic material in order to improve the blow-out action. This is unnecessary with the present arrangement and simplifies the fabrication of the plates. It is also possible to reduce the number of plates, whereby there is a saving in costs and weight for a circuit breaker of the saine capacity.

I claim:

1. A circuit breaker of the magnetic blow-out type comprising a pair of load contacts, said load contacts being movable relative to each other in a rst vertical plane between an engaged and a disengaged position, a pair of main arcing horns located in said first plane and to which an arc established upon disengagement of said load contacts is initially transferred, a plurality of alternately arranged first and second arc chambers located above said main arcing horns in side-by-side relation and which are established by a plurality of parallel spaced walls oriented in parallel vertical planes normal to said rst vertical plane, a pair of auxiliary arcing horns located in each of said first arc chambers, each said pair of auxiliary arcing horns being located in spaced relation in a plane parallel with said Walls which establish said arc chamber, and a blast coil located in each of said second arc chambers, said blast coils and said auxiliary arcing horns being connected electrically in series by the arc established between said pair of main arcing horns.

2. A circuit breaker as defined in claim 1 wherein each said blast coil includes an iron core within the same.

3. A circuit breaker as detined in claim 1 wherein each said blast coil includes a short-circuited secondary winding inductively coupled thereto.

4. A circuit breaker as dened in claim 1 wherein each said blast coil includes an iron core and a short-circuited secondary coil surrounding said iron core.

5. A circuit breaker as dened in claim l wherein the blast coil in each said second arc chamber is connected directly with an auxiliary arcing horn in the next adjacent rst arc chamber.

6. A circuit breaker as defined in claim 5 wherein each said blast coil and the correlated auxiliary arcing horn are constituted from a single length of conductive material.

7. A circuit breaker as dened in claim l wherein the lower end of each said blast coil is located below the lowest point on said auxiliary arcing horns.

8. A circuit breaker as defined in claim l wherein the lower end of each said blast coil is located below the lowest point on said auxiliary arcing horns and the upper ends of different turns on each said blast coil are staggered in height.

References Cited by the Examiner UNlTED STATES PATENTS 2,847,540 8/58 Pfeiffer et a1. ZOO-147 2,918,552 12/59 Fust ZOO-147 FOREIGN PATENTS 1,035,727 8/58 Germany. 1,072,291 12/59 Germany.

BERNARD A. GILHEANY, Primary Examiner. ROBERT K. SCHAEFER, Examiner.

Claims

1. A CIRCUIT BREAKER OF THE MAGNETIC BLOW-OUT TYPE COMPRISING A PAIR OF LOAD CONTACTS, SAID LOAD CONTACTS BEING MOVABLE RELATIVE TO EACH OTHER IN A FIRST VERTICAL PLANE BETWEEN AN ENGAGED AND A DISENGAGED POSITION, A PAIR OF MAIN ARCING HORNS LOCATED IN SAID FIRST PLANE AND TO WHICH AN ARC ESTABLISHED UPON EISENGAGEMENT OF SAID LOAD CONTACTS IN INITIALLY TRANSFERRED, A PLURALITY OF ALTERNATELY ARRANGED FIRST AND SECOND ARC CHAMBERS LOCATED ABOVE SAID MAIN ARCING HORNS IN SIDE-BY-SIDE RELATION AND WHICH ARE ESTABLICHED BY A PLURALITY OF PARALLEL SPACED WALLS ORIENTED IN PARALLEL VERTICAL PLANES NORMAL TO SAID FIRST VERTICAL PLANE, A PAIR OF AUXILIARY ARCING HORNS LOCATED IN EACH OF SAID FIRST ARC CHAMBERS, EACH SAID PAIR OF AUXILILARY ARCING HORNS BEING LOCATED IN SPACED RELATION IN A PLANE PARALLEL WITH SAID WALLS WHICH ESTABLISH SAID ARC CHAMBER, AND A BLAST COIL LOCATED IN EACH OF SAID SECOND ARC CHAMBERS, SAID BLAST COILS AND SAID AUXILIARY ARCING HORNS BEING CONNECTED ELECTRICALLY IN SERIES BY THE ARC ESTABLISHED BETWEEN SAID PAIR OF MAIN ARCING HORNS.