US2239940A

US2239940A - Current interrupting apparatus

Info

Publication number: US2239940A
Application number: US311034A
Authority: US
Inventors: Charles L Stroup
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-12-26
Filing date: 1939-12-26
Publication date: 1941-04-29
Anticipated expiration: 1958-04-29

Description

April 29, 1941. c, L, STROUP cunnrm m-manurrme APPARATUS 2 Sheets-Sheet 1 Filed Dec. 26, 1939 Inueni'vn- Patented Apr. 29, 1941 UNITED STATES. PATENT OFFICE cuaasN-r mraaaurmc measure can! L. Stroup, Oak Park, 111. Application December 26, 1939, Serial No. 311,034

' 1 Claims. (01. 115-20) My invention relates generally to electrical apparatus and it has particular relation to current interrupting apparatus such as lightning arresters, circuit breakers, and i'uses, in which are extinction is eflfected by means of a blast resulting from the creation or the arc and acting to blow out the arc.

This application is a continuation-in-part oi.

my co-pending application, Serial No. 256,638,

filed February 16, 1939.

An object of my invention is to provide for assisting in extinguishing an arc in a new and improved manner by directing across its path a blast created as a result of the arc. v

Another object of my invention is to confine under pressure in an arc space a gas generated as a result of the creation of an arc during a period of maximum current fiow therethrough and to release the gas in the form of a blast across the arc path during a period of minimum current fiow to deionize the same and prevent restriking of the arc.

Still another object of my invention is to provide for drawing an arc in a relatively smallarc passageway and to direct through a relatively large blast passageway and across the relatively small arc passageway a blast of gas generated by the are for deionizing the arc path.

A further object of my invention is to provide for drawing an arc in a. relatively small arc passageway during a period of maximum current flow therethrough and at the same time confining under pressure in the arc space a gas generated as a result of the arc and then releasing the gas in the form of a blast through a relatively large blast passageway and across the relatively small arc passageway during a period of minimum current fiow to deionize the arc path and prevent restriking of the arc.

Other objects of my invention will, in part, be obvious, and in part appear hereinafter.

Accordingly, my invention is disclosed in the embodiments thereof shown in the accompanying drawings, and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the description hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

While I have chosen to disclose my invention as employed in a lightning arrester, it will be apparent that it may also be employed for use nature and scope of my invention, reference may be had to the following detailed description, taken in connection with the accompanying drawings, in which:

Figure 1 is a vertical sectional view oi. a lightning arrester unit illustrating the principles of my invention;

Figure 2 is a vertical sectional view through a lightning arrested unit illustrating a working embodiment of my invention:

Figure 3 is a sectional view taken on line 3-3 I of Figure 2;

in other types of current interrupters, such as fuses or circuit breakers, for interrupting alternating curent at power frequency, i. e., cycles,

as illustrated in my copending application Serial No. 293,237, filed September 2, 1939, the disclosure in which is intended to form a part of and to be included in the instant disclosure.

For a more complete understanding of the Figure 4 is a sectional view taken on line 4-4 of Figure 2; and

Figure 5 is a view, partly in vertical section and partly in side elevation, of a complete lightning arrester illustrating another embodiment of my invention.

With a view of illustrating the principles of my invention, reference may now be had to Figure 1 of the drawings in which the reference character l0 designates, generally, a lightning arrester unit comprising a fiber casing ii and upper and lower electrodes or terminals i2 and i 3. The electrode i2 has a boss i4 depending from the under side thereof and the discharge voltage of the lightning arrester unit it is determined by the distance between the boss i4 and the lower electrode IS. A block of fiber material i5 is disposed within the casing i i adjacent to the lower electrode I 3 and spaced from the upper electrode I! to provide a chamber ii. In order to provide an air gap between the boss II and electrode l3 an arc passageway H of relatively small area or bore is formed in the fiber block as shown. A blast passageway I 8 of relatively greater length and area than the arc passageway I1 is provided diagonally through the fiber block 15, terminating in the chamber is and at the aperture or hole I! provided in the .lower electrode ii. The passageway it comprises a blast passageway for the discharge of gases generated by the arc transversely of the arc in the arc passageway IT. The upper electrode I 2 and the lowerelectrode B may be connected to line and ground respectively, as shown.

While the blast passageway II is illustrated as terminating in the aperture I! oi! the lower electrode l3, it will be understood that it may terminate otherwise. For example, it may vent directly through the side wall of the casing II. The principal requirement is that the gas which is evolved from the fiber block l5 during a period of maximum current flow and confined under pressure in the chamber I be able to discharge .in the form of a blast across the arc passageway l1 during a, period of minimum current flow for deionizing at least a portion of this are passageway and preventing restriking therethrough.

A metallic conductor in the form of a plug in passage 11 immediately above the intersection of passageways II and I. may be utilized to insure an upward fiow only of the gas generated in the upper end of the passage II. This prevents escape of the 'gas there generated directly into the passage II. In this construction the are obviously is formed in two sections. The same feature may be introduced into the embodiment shown in Figures 2, 3, 4 and 5.

The function and operation of the lightning arrester unit II will be seen to be as follows: When a voltage equal to or greater than that of the discharge voltage is impressed on the lightning arrester unit ll, an arc will be formed between the boss I4 and the electrode I! through the arc passageway H. The heat of the arc thus established will evolve gases, substantially water vapor, from the surfaces of the fiber casing Ii and block II as is well understood by the art in connection with fuses and other electrical protective devices. The evolution of the hot gases is so rapid that a high pressure will be set up in the chamber it and the hot gases will be expelled through the blast passageway II with tremendous velocity and pressure. Any part of the original are carried over or transferred into the blast passageway It will be extinguished therein by the hot gases expelled therethrough. The passageways i1 and I8 intersect each other as shown, and the hot gases expelled through the blast passageway II with such tremendous velocity and pressure, immediately on crossing the arc passageway I! at the intersection, extinguish the are established in the arc passageway The function and operation of the lightning arrester unit I. on discharge will be seen to be analogous to that of allowing an arc to be formed between electrodes separated by a short air gap through fiber material and then exposing a short length of the arc and blowing a violent blast of arc extinguishing gas across the space which is exposed so that the space is deionized and the arc cannot sustain itself in that region and is extinguished. Such action is carried out automatically in the -lightning arrester unit II by having the short are passageway ll of small area intersecting the longer passageway it of greater area.

I have found that the working embodiment of my invention shown in connection with Figures 2, 3, and 4 of the drawings has certain practical design characteristics which are superior to the embodiment shown in Figure 1. Referring now particularly to Figures 2, 3, and 4 of the drawings. a lightning arrester unit is designated, generally, at 25 which has the same general operating characteristics as thosedescribed hereinbefore in connection with the lightning arrester unit III of Figure 1. The lightning arrester unit 25 comprises a fiber housing or casing 26 with an upper electrode 21 and a lower electrode 28 closing of! the upper and lower ends respectively of the housing 26. A boss 29 projects from the under side of the upper electrode 21 to fix a definite spot from which an arc may be established. The discharge voltage of the lightning arrester unit 25 is determined by the distance between the boss 29 and the lower electrode 28. A cylindrical fiber block 30 is provided within the housing 2 resting on the lower electrode 28 and spaced from the upper electrode 29 to form a chamber 2|. A set screw 22 may be provided in a path in the upper electrode 21 to maintain the fiber block 2| in position.

In order for the lightning arrester unit 2! to have the same general operating characteristics as the lightning arrester unit III of Figure 1. passageways are provided therein corresponding to the passageways l1 and I! of the lightning arrester unit I I. The narrow space. indicated at 22, between the side of the fiber block II and the inner surface of the housing 2! constitutes a substantially direct are eway of constricted area between the boss 22 and electrode 2| which corresponds to the arc passageway ll,

"Figure 1. With a view to providing a blast pas.-

sageway corresponding to the longer blast passageway II of greater area (Figure 1), holes 24 and 2! are drilled into the fiber block 20 as shown. The holes 24 and 25 do not communicate directly with each other, and extend only part way into the fiber block 20. The upper hole communicates with the chamber 2| and the lower hole 25' registers with an aperture or hole 28 in the bottom electrode 28.

As previously indicated, the lower hole could vent through the side wall of the casing 20, if desired, rather than through the hole 26 in the bottom electrode 28.

With a view of providing a passageway to interconnect the holes II and 25, a groove 21 is provided in the lateral surface of the fiber block 2|. It will be noted that the groove 21 is not continuous, but terminates at non-communicating ends. One end of the groove 31 is connected with the hole 34 through a small passageway 28 and the other end of the groove 21 communicates with the hole 35 through a small hole 38. The arrows indicate the path followed by gases expelled from the chamber 3| out to and through the aperture 38. The blast passageway thus provided by the holes 34 and 35 and the groove 21 corresponds to the blast passageway I! (Figure 1), but is substantially longer. Its length can be still further increased by having the groove 31 make several turns around the surface of the fiber block 20 before the ends thereof are connected to or with the holes 34 and 35. As an alternative to the groove 31 in the lateral surface of the fiber block 30, a similar groove may be provided in the inner surface of the fiber housing 20.

To complete the assembly of the lightning arrester unit 25, a line terminal 4| may be provided which screws into a tap in the upper electrode 21, and a ground terminal 42 may be provided which screws into the lower electrode 22.

The operation of the lightning arrester unit 25 will be observed to be as follows: When a voltage equal to or greater than the discharge voltage is applied to the lightning arrester unit 25, an arc is formed in the narrow space 33 between the boss 29 and the lower electrode 28. The heating eil'ect of this are on the adjacent fiber surfaces of the housing 26 and block 30 causes hot gases to be evolved therefrom. Accordingly, a pressure will be built up in the chamber II and the hot gases will be expelled under high pressure through the hole 34 out into the groove 31, from the groove 21 into the lower hole 35, and out through the aperture 36, as indicated by the arrows 40. Any part of the are between the boss 29 and electrode 28 which may be carried or transferred into the blast passageway designated by the arrows M will be quickly extinguished or blown out. It will be noted that the groove 31 intersects the narrow space 32 between the side of the fiber block Ill and the inside of the housing 28. The hot gases and vapors expelled through the groove 31 at tremendous velocity and pressure extinguish and cut on the are formed in this narrow space 33. Actual tests have shown that this arrangement of intersecting passageways will extinguish the arc on a 2300-volt circuit at the end of one or two half cycles.

Another embodiment of my invention is disclosed in connection with the lightning arrester designated generally at 5| in Figure 5 of the drawings. The lightning arrester 50, which may be mounted on a cross arm or other location, comprises an inverted porcelain cup 5| and a post type insulator 52 interconnected by a neck 53.

A lightning arrester unit 54 may be' disposed within the inverted cup 5| with its upperterminal 55 projecting up into a recess 56 in the side of the neck 53. A conducting member 51 projects into the recess 58 and through an aper-' ture in the terminal 55, and is rotatable therein. The conducting member 51 carries another conducting member 58 fixedly mounted thereon. When the conducting member 58 is in a vertical position it is separated from a line terminal 59 carried on the top of the post type insulator 52 by an air gap 60. The conducting member 5'! is rotatable in the terminal 55 and rests on the bottom of the recess 56. A relatively soft washer BI is provided around the terminal 55 between the top of the lightning arrester unit 54 and the top surface of the inverted cup 5| to prevent contact therebetween. That is, tightening the lightning arrester unit 54 against the inside of the inverted cup 5| which might cause breakage thereof, is thereby prevented.

The lightning arrester unit 54' may be removed from and replaced in the inverted cup of the lightning arrester 50 as follows: To insert the lightning arrester unit 54 in the lightning arrester 58, the conducting member 58 is first rotated away from the terminal 59 by a switch stick if it has not already been so moved. The lightning arrester unit 54 is then screw'ed onto the bottom of the terminal 55 until the conducting member 51 is drawn down tightly against the bottom of the recess 56. The conducting member 58 is then turned up into place as shown in Figure 5 by a switch stick, and the ground terminal is connected as shown. To remove the lightning arrester unit from the lightning arrester 50, the conducting member 58 is turned down by a switch stick and the lightning arrester unit 54 is then unscrewed from the terminal 55.

It is important that the air gap 60 be provided in connection with the lightning arrester 50. If theline were directly connected to the terminal 55 of the lightning arrester unit54, the voltage of the line to ground would be continually impressed on the lightning arrester unit 54. Such impressed voltage would cause minute currents to leak through the lightning arrester unit 54 over the fiber surfaces thereof. Such leakage currents would eventually cause the surfaces of the fiber elements in the lightning arrester unit 54 to become charred and thereby destroy the unit. It will be understood that the air gap 60 and the air gap between the upper and lower electrodes of the lightning arrester unit 54 have a lower break-down voltage than that of the transformer or other apparatus which is to be protected by the lightning arrester 50.

While I speak of an arc as though it were a single continuous are it is to be understood that the are referred to herein may be broken up into sections by intervening conductors.

Since certain further changes can be made in the foregoing constructions, and different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter shown in the accompanying drawings or described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

I claim. as my invention:

1. A lightning arrester comprising, in combination, a fiber housing, an upper electrode closing on the upper end of said fiber housing, a lower electrode closing off the lower end of said fiber housing, an aperture in said lower electrode, a fiber block fitting within said fiber housing, a narrow space between the lateral surface of said fiber block and the inner surface of said fiber housing, a chamber between the top of said fiber block and said upper electrode, a groove in the lateral surface of said fiber block, an upper passageway interconnecting said groove with said chamber and a lower passageway interconnecting said groove with said aperture, said narrow space between the lateral surface of said fiber block and the inner surface of said fiber housing constituting an arc passageway of restricted area between said upper and lower electrodes, said groove and said upper and lower passageways in communication therewith constituting a blast passageway of greater area and length between said upper and lower electrodes than said are passageway, and arc extinguishing gases being given off from said fiber housing and fiber block when exposed to an electric arc.

2. A lightning arrester comprising, in combination, a cylindrical fiber housing, an upper electrode closing off the upper end of said cylindrical fiber housing, a boss projecting from the underside of said upper electrode, a lower electrode closing off the lower end of said cylindrical fiber housing, an aperture in said lower electrode, a cylindrical fiber block fitting within said cylindrical fiber housing, a narrow space between the lateral surface of said cylindrical fiber block and the inner surface of said cylindrical fiber housing, a chamber between the top of said cylindrical fiber block and said upper electrode, a

groove in the lateral surface of said cylindrical fiber block, an upper passageway interconnecting said groove with said chamber, and a lower passageway interconnecting said groove with said aperture, said narrow space between the lateral surface of said cylindrical fiber block and the inner surface of said cylindrical fiber housing constituting an arc passageway of restricted area for arcs formed between said boss and said lower electrode, said groove and said upper and lower passageways in communication therewith constituting a blast passageway of greater area and length for arcs formed between said boss and said lower electrode than said are passageway, and are extinguishing gases being evolved from said cylindrical fiber housing and from said cylindrical fiber block when exposed to an electric arc.

3. A lightning arrester comprising, in combination, a. fiber housing, an upper electrode closing oil the upper end of said fiber housing, a lower electrode closing off the lower end of said fiber housing, an aperture in said lower electrode, a fiber block fitting within said fiber housing, a narrow space between the lateral surface of said fiber block and the inner surface of said fiber housing, a chamber between the top of said fiber block and said upper electrode, a passageway extending around the lateral surface of said fiber block and intersecting said narrow space between the lateral surface of said fiber block and the inner surface of said fiber housing, and means interconnecting said passageway with said chamber and said aperture, said narrow space between the lateral surface of said fiber block and the inner surface of said fiber housing constituting an arc passageway of restricted area between said upper and lower electrodes, said passageway extending around the lateral surface of said fiber block together with said interconnecting means constituting a blast passageway between said upper and lower electrodes, and are extinguishing gases being given of! from said fiber housing and fiber block when exposed to an electric are.

4. A lightning arrester comprising, in combination, a fiber housing, an upper electrode closing of! the upper end of said fiber housing, a lower electrode closing off the lower end of said fiber housing, an aperture in said lower electrode, a fiber block fitting within said fiber housing, a narrow space between the lateral surface of said fiber block and the inner surface of said fiber housing, a chamber between the top of said fiber block and said upper electrode, a groove in the lateral surface of said fiber block, an upper passageway interconnecting said groove with said chamber and a lower passageway interconnectlng said groove with said aperture, said narrow space between the lateral surface of said fiber block and the inner surface of said fiber housing constituting an arc passageway of restricted area between said upper and lower electrodes, said groove and said upper and lower passageways in communication therewith constituting a blast passageway of greater area and length between said upper and lower electrodes, and are extinguishing gases being given off from said fiber housing and fiber block when exposed to an electric arc, an are being struck between said upper and lower electrodes through said are passageway when a voltage equal to the discharge voltage of said lightning arrester unit is impressed thereon, and said are causing said are e gases to be evolved which drive through said blast passageway under high pressure whereby said are is extinguished.-

5. A lightning arrester comprising, in combination, a cylindrical fiber housing, an upper electrode closing of! the upper end of said cylindrical fiber housing, a boss projecting from the under side of said upper electrode, a lower electrode closing of! the lower end of said cylindrical fiber housing, an aperture in said lower electrode, a cylindrical fiber block fitting within said cylindrical fiber housing, a narrow space between the lateral surface of said cylindrical fiber block and the inner surface of said cylindrical fiber housing, a chamber between the top of said cylindrical fiber block and said upper electrode, a groove in the lateral surface of said cylindrical fiber block, an upper passageway interconnecting said groove with said chamber, and a lower passageway interconnecting said groove with said aperture, said narrow space between the lateral surface of said cylindrical fiber block and the inner surface of said cylindrical fiber housing constituting an arc passageway of restricted area for arcs formed between said boss and said lower electrode, said groove and said upper and lower passageways in communication therewith constituting a blast passageway of greater area and length for area formed between said boss and said lower electrode, and are extinguishing gases being evolved from said cylindrical fiber housing and from said cylindrical fiber block when exposed to an electric are, an are being struck between said upper and lower electrodes through said are passageway when a voltage equal to the discharge voltage of said lightning arrester unit is impressed thereon, and said are causing said are extinguishing gases to be evolved which drive through said blast passageway under high pressure whereby said are is extinguished.

6. A lightning arrester comprising, in combination, a fiber housing, an upper electrode closing of! the upper end of said fiber housing, a lower electrode'closing oi! the lower end of said fiber housing, an aperture in said lower electrode, a fiber block fitting within said fiber housing, a narrow space between the lateral surface of said fiber block and the inner surface of said fiber housing, a chamber between the top of said fiberblock and said upper electrode, a passageway extending around the lateral surface of said .fiber block and intersecting said narow space between the lateral surface of said fiber block and the inner surface of said fiber housing, and means interconnecting said passageway with said chamber and said aperture, said narrow space between the lateral surface of said fiber block and the inner surface of said fiber housing constituting an arc passageway of restricted area between said upper and lower electrodes, said passageway extending around the lateral surface or said fiber block together with said interconnecting means constituting a blast passageway between said upper and lower electrodes, and are extinguishing gases being given off from said fiber housing and fiber block when exposed to an electric are, an are being struck between said upper and lower electrodes through said are passaway when a voltage equal to the discharge voltage of said lightning arrester unit is impressedthereon, and said are causing said are extinguishing gases to be evolved which drive through said blast passageway under high pressure whereby said are is extinguished.

7. A lightning arrester comprising, in combination, an inverted cup of insulating material, a post type insulator disposed above said inverted cup, a neck interconnecting said inverted cup and said post type insulator, a recess in the side of said neck, a lightning arrester unit comprising upper and lower electrodes disposed within said inverted cup, a first conducting member projecting from the upper electrode of said lightning arrester unit up into the recess in said neck, a second conducting member rotatabiy connected with said first conductor and resting on the bottom of the recess in said neck, a third conducting member fixedly connected to said second conducting member, a terminal carried by said post type insulator, an air gap between said third conducting member and said terminal, and means for regulating the bearing pressure of said second conducting member on the bottom of the recess in said neck whereby the free rotation of said second conducting member and said third conducting member fixedly connected therewith is prevented when said lightning arrester unit is secured in position in said inverted cup, external force being required to rotate said second and third conducting members to increase the length of said air gap.

CHARLES L. STROUP.