US2572625A

US2572625A - Arc extinguishing attachment for air-break switches

Info

Publication number: US2572625A
Application number: US151388A
Authority: US
Inventors: Tomlinson F Johnson
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-03-23
Filing date: 1950-03-23
Publication date: 1951-10-23
Anticipated expiration: 1968-10-23

Description

Oct. 23, 1951 T. F. JOHNSON 2,572,525

ARC EXTINGUISHING ATTACHMENT FOR AIRBREAK SWITCHES Filed March 23, .1950 2 smu -5mm 1 INVENTOR Z'E domvsolv ATTORNEYS Oct. 23, 1951 T. F. JOHNSON A RC EXTINGUISHING ATTACHMENT FOR AIR-BREAK SWITCHES 2 SHEETS-SHEET 2 Filed March 23, 1950 INVENTOR It yo'mvsmv BY. Z a ,,M

ATTORNEYS Patented Oct. 23, 1951 ARC EXTINGUISHING ATTACHMENTFOR AIR-BREAK SWITCHES Tomlinson F. Johnson, Atlanta, Ga.

Application March 23, 1950,.Serial No. 151,388.

This invention relates to high tensionswitches or. circuit interrupters having provision for ex.- tinguishing the are under heavy loads whenthe switches are operated to isolate portions of a line. Among otherrobjects, the invention aims to providea simplified and effective are extinguishing or. interrupter attachment for useon group operated air-break switches, whereby theswitches maybe employed.for disconnecting or isolati sections ofhcavy voltage lines operating .-under full loads.

Another aim ofthe invention is ..to providev a simplified and. effective arc. extinguisher :or. inter? rupter device, adapted to beappliedto ordinary air-break: switches having vertically -tiltable. or swinging blades and equipped with arcing horns.

Other aims and advantages of the invention will appear in the specification when .considered in connection with the accompanying drawings, wherein:

Fig. 1 is a side elevation of a single switch having the preferred form ofsattachment applied thereto;

Fig. 2 is a fragmentary .view, similar to. Fig. 1, showing the switch .in its partially opened .posie tion;

Fig. 3 is a fragmentary top. plan view of the arc extinguishing attachment shown in Fig. 1;

Fig. 4is .a fragmentary vertical sectional .view of the attachment;

Fig. 5 is a sectional view taken on the. line 5-:5 of Fig. 4; and

Fig. 6 is a sectional view taken on the-line 66 of Fig. 4.

Group operated air-break switches ofthe type disclosed are employed for disconnecting and isolating sections of high voltage transmission lines. Unless they are provided with special load breaking attachments, such switches cannot be operated under full load conditions. They can break only limited transformer charging currents and will be severely damaged, due to arcing, under full loads. It is, therefore, a principal object'of the present invention to provide a simipliiied and very effective are extinguishing attachmentfor high tension, air-break switches, which will enable them to be operated under load conditionsywith out damage to the switch contacts.

Referring more particularly to the drawings,

6 Claims. (Cl. 209-146) horns 16 made of heavy wire, such as silicon bronze.

The stationary contact is of the usual typeand includes a -bracket I! having a base plate [8 to which: the conductor I9 is connected. In accordance with I this invention, a supporting bracket plate 20 is secured to the base plate 18: and has upstanding ears 2| for carrying the arcing attachment. A horizontal shelf member 22 has avertical arm 23 secured to the upstanding ears 2| bya pair of bolts 24. This shelf also has anintegral upstanding ear to whichan inverted,' U-.shaped arc horn 26 is connected by a clamping plate 2? and bolts 28. The movable arcingliorns [5 are adapted to straddle thestationary arcinghorns in the usual manner.

The outer end portion ofthe shelf is provided with a trough-shaped supporting member 29 having-an upstanding flange 30 at its front end sides, so thatwater will drain out of it and cannot-accumulate and freeze in it. An upstanding arcing, conductor-rod 3| is screwthreadedinto a vertical opening in the trough-shaped member. An interru ter tube 32, preferably made of hard, fibrous insulating material, i supported for slidingmoyementon thearcingconductor rod 3| -by means of a hub-shaped guide. member 33, made of alumihumor other'light weight material, It loosely engages thelower endof therod and has a cylindricaliiange Stoonnectedto thelower end of the tubeby means of apair of diametrically opposite arms 35,. the arrangement being such thatthehub member does not close the lower end of the tube and rests on thebottom ofthetroughshapedmemberii). An aluminumcylinder or skirt-3B surrounds the guidemember 33 andex; tends to, a point near the bottom efthe trough}? to direct-the gas'into the troughf Thecylindrical sleeve and flan e 3-; of the hub-shaped guide member are shown as being connected t0; the lower end of the tubeby screws 31. Thgupper end of the tube isshownashavinga re novable bronze plug member 38; inserted therein with asvaeat a pair of radial lugs 39 engaging radial notches in the end of the tube. It is held in place by a cap 40 telescoped over and secured to the upper end of the tube by screws 4|. The cap is shown as having a plurality of cam shaped ribs :22 adapted to guide the wires of the arcing horns l6 downwardly over the cap to engage their lower edges 43, so that, when the switch is opened, the horns will lift the tube. The lower portions of the cam shaped ribs are shown as being rounded at M to act as guiding cams, so that the wires of the horn 56 will spread apart and be disengaged from the cap in case the tube is stuck on the arcing rod 31 during its lifting movement. A short conductor rod 45 is shown as being threaded through an upstanding boss M on the cap member 39 and through the upper end portion of the plug 38 so that its lower end contacts the upper end of the arcing rod 3|. It is held in its adjusted position by a jamb nut 41 and extends only a short distance above the upper end of the cap. This rod also serves as a guide for the movable arcing horns it when the switch is being closed.

As will be seen in Fig, 1, the lower ends or shoulders of the cap member 39 are above the level of the upper end of the stationary U-shaped horn 26, so that the movable arcing horns IE will engage the bottom of the cap during the opening movement of the switch blade to re-establish the circuit through the interrupter and lift the tube as the blade swings open. As soon as the tube is lifted, the arc will be transferred to the tube between the contact member 38 and the upper end of the arcing rod. When this occurs, the arc will melt a minute portion of the contact rod 45 and gasefy it, due to the intense heat. This will create an upward pressure in the tube which will assist the moving horns IS in raising the interrupter tube to the top of its stroke and thus rupture the are by very rapid attenuation. When the lower end of the contact rod 55 is burned off, it can easily be re-adjusted to make good contact with the upper end of the arcing rod 3|.

The arc drawn in the tube is ruptured or extinguished before the tube reaches the upper limit of its stroke. The stroke is shown as being limited by means of an annular stop collar 48 adjustably mounted on the arcing rod 3:, so that the hub-shaped guide member 33 strikes it as the tube is lifted by the movable arcing horns l6 and the free ends of the horns slide out of engagement with the cap during the final opening movement of the blade. The hot gas or flame is discharged downwardly from the tube into the troughshaped member 29, and the flange 30 prevents it from damaging the stationary contact. Thus, the trough-shaped member serves the dual purpose of supporting the tube and acting as a shield for protecting the stationary contact of the switch.

When the arc is extinguished, the tube will fall by gravity to the re-set position, shown in Fig. 5. During the closing movement of the switch, the fork-shaped arcing horns [6 will straddle the upstanding, contact rod 45 and will be guided over the top of the cap by the cam-shaped ribs 42 to straddle the stationary U-shaped horn 26. Incidentally, the width of the U-shaped horn corresponds with the diameter of the tube 32, so that the forks of the arcing horns IE will readily engage the shoulders 43 at the bottom of the cap when the switch is open and the forks are disengaged from the stationary horn.

From the foregoing description, it will be seen that the arc extinguishing attachment is very simple in its construction and operation. It is 4 so designed that it can be applied to airbreak switches of diiferent types and has proved to be effective in breaking heavily loaded circuits without damage to the switch.

Obviously, the invention is not restricted to the particular embodiment thereof herein shown and described, but is capable of various modifications within the scope of the appended claims.

What is claimed is:

1. An arc extinguishing attachment for an airbreak switch having a vertically swinging blade and a pair of parallel arcing horns, comprising a vertically movable interrupter tube of insulating material mounted on the stationary contact and having a metal cap member at its upper end; and a stationary arcing conductor rod electrically connected to the stationary switch contact and supported within the tube with its upper end normally in contact with said metal cap; the movable arcing horns being engageable with said cap as the switch blade is raised to its open position to lift the tube and start an are between the cap and th arcing conductor rod, whereby gas pressure created by the arc will force the tube upwardly to elongate and extinguish the arc.

2. An arc extinguishing attachment for an airbreak switch, as set forth in claim 1, wherein the arcing conductor rod and movable tube are mounted on a bracket secured to the stationary switch contact; and a hub-shaped guide member slidably mounted on the arcing conductor rod connected to the bottom of the tube to confine the tube to move vertically on the rod; and a stop member on the rod coacting with said guide member to limit the upward movement of the tube.

3. An arc extinguishing attachment for an airbreak switch, as set forth in claim 1, wherein the arcing conductor rod and movable tube are supported on a bracket secured to the stationary switch contact; a vertical, inverted, U-shaped arcing horn parallel with and adjacent to said tube terminating slightly below the cap on said tube and poistioned to be straddled by the arcing horns on the switch blade, whereby the current flow is established through the tube cap and arcing conductor rod as the movable arcing horns are swung above the U-shaped horn; means to guide the tube to slide upwardly on the conductor rod; and means to limit the upward movement of the tube.

4. An arc extinguishing attachment for an airbreak switch, as set forth in claim 1, wherein the cap on said tube has a plurality of vertical ribs to act as spreading cams for the horns; and said ribs having shoulders at their bottom edges to be engaged by the movable arcing horns.

5. An arc extinguishing attachment for an airbreak switch having a vertically swinging blade and a pair of parallel arcing horns, comprising a vertically movable interrupter tube of insulating material mounted on the stationary contact and having a metal cap member at its upper end; a stationary arcing conductor rod electrically connected to the stationary switch contact and supported within the tube with its upper end normally in contact with said metal cap; the movable arcing horns being engageable with said cap as the switch blade is raised to its open position to lift the tube and start an are between the cap and the arcing conductor rod, whereby gas pressure created by the arc will force the tube upwardly to elongate and extinguish the arc; vertical cam-shaped ribs on the cap acting as spreading cams for the horns; said ribs having shoulders at their bottom edges to be engaged by the movable arcing horns; a vertical, inverted, U- shaped horn spaced from the tube with its upper end terminating short of the cap on the tube; and a short conductor rod extending through and adjustably connected to the cap in contact with the upper end of said arcing conductor rod.

6. An arc extinguishing attachment for an airbreak switch, as set forth in claim 1, wherein the arcing conductor rod and movable tube are supported on a horizontal trough-shaped member with the lower, open end of the tube above the bottom of said trough-shaped member, said TOMLINSON F. JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Pittman et a1 Nov. 9, 1937 Number