US2559599A - Electrical surge arrester - Google Patents

Description

July 10, 1951 L. L. CRUMP H Al. 2,559,599

ELECTRICAL SURGE ARRES'IER Filed June 7, 1947 I l l I FIG. 2

INVENTOR5 LINDELL LLOYD CRUMP CHARLES Aom Fox ATTO RN EY Patented July 10, 1951 ELECTRICAL SURGE ARRESTER Lindeil Lloyd Crump,

Fox,

poration of Missouri Kirkwood, and Charles Adin Oakland Village, Mo., assignors to James R. Kearney Corporation,

St. Louis, Mo., a cor- Applieatlon June 7, 1947, Serial No. 753,314 5 Claims. 17 -30) This invention relates generally to electrical protective devices which are adapted for use in protecting electrical circuits and the equipment associated therewith from the damaging efiects of surges resulting from lightning and other causes, the predominant object of the invention being to provide an electrical protective device of this type which includes spaced elements that providefian air gap, and which is of such improved construction and arrangement that heavy surges will not permanently disturb the setting of the air gap.

Prior to this invention, surge arresters of the general type of the one disclosed herein have been employed which were provided each with an air gap produced by spaced elements that were fixedly secured in their related positions to provide the air gap. In the use of these earlier surge arresters it has been found that when an arc was formed across the air gap by a heavy surge, there was a tendency for one of the elements which produced the air gap to be permanently bent, or otherwise displaced from its normal gap-producing position, so that the width of the air gap was permanently increased with each action of the surge arrester with the result that the surge arrester was eventually rendered inefiective for the purpose for which it was installed.

The surge arrester of the present invention is of such improved construction and arrangemen that the difliculties recited above are eliminated in the foperation of the surge arrester, this re sult being attained by mounting one of the gap producing elements of the surge arrester for such movement that the air gap may be increased on passage thereacross of a heavy surge and so that saidmovabiy mounted element will return to its normal position after the surge has passed. Thus, while the passage across the air gap of the surge arrester of a heavy surge may increase the width of said air gap momentarily during such passage of the heavy surge, the width of the air gap is not permanently altered, as was frequently the case heretofore, but, instead, the movably mounted gap-producing element returns to its normal position after being moved by a heavy surge so as to provide an air gap of the proper setting for efliciently by-passing subsequent surges which are imposed on the circuit protected by the surge arrester.

Fig. 1 is a front elevation of the improved surge arrester of the present invention.

Fig. 2 is a view partly in side elevation and partLvin vertical section of the surge arrester illustrated in Fig. 1.

' contacts with the lower face of In the drawing wherein is shown for purposes of illustration, merely, one embodiment of the invention, A designates the improved surge arrester generally. The surge arrester A includes as a part of its structure an insulator I, preferably, thoughnot necessarily, of the petticoat type, said insulator having formed therethrough from end to end thereof an opening 2.- Mounted at the upper end of the insulator I is a head member 3 which is formed from 'metal, or other material which is a good conductor of electrical energy, said head member being illustrated as having a curved top and as being provided with an annular flange 4 from which is extended downwardly a portion 5 whose bottom face contacts with the top face of the insulator" I. At the lower end of the insulator I a groundterminal 6 is provided, this ground terminal being formed from metal, or other electrical conductive material. The ground terminal 5 comprises a lower tapered portion 1, an annular flange portion 8, and a portion 9 which extends upwardly from said flange portion and whose top face the insulator I. The portion 9 and the flange portion 8 of the ground terminal 6 have formed centrally therethrough a screwthreaded opening I", and this opening I0 communicates with a vent opening II which is open at the front of the tapered portion I of the ground terminal 6.

Disposed within the opening 2 of the insulator I and projected beyond the opposite ends thereof is a tubular element I2 which is formed of horn fiber, or other material which is characterized by the ability to give oif gas in the presence of the heat of an electrical are which tends to extinguish the arc. The tubular element I2 is externally screwthreaded at its upper end, as is shown in Fig. 2, and this screwthreaded upper portion of said tubular element is screwed into a screwthreaded opening I3 which is formed in the head portion 3. Likewise, the lower portion of the tubular element I2 is externally screwthreaded and this lower, screwthreaded portion of said tubular element is screwed into the screwthreaded opening III of the ground terminal I so that the vent opening II of said ground terminal communicates with the interior of the tubular element I2, as is shown in Fig. 2. From the foregoing it is obvious that the insulator I. the head member 3, and the ground terminal I are held in their assembled relation by the tubular element I2.

Disposed within the tubular element I 2 is an electrode II which is provided with an externallv screwthreaded upper end portion that is screwed assasee into a screwthreaded opening it formed in the head member 3. The electrode it extends downwardly from its point of attachment to the head member 3 to a point spaced upwardly from the ground terminal '3 so as to provide a gap it within the tubular element i2 and between the lower end of the electrode I4 and the ground terminal 5.

Supported by the insulator I is a pair of members I1 and I8, the member I1 being disposed at the front of the insulator while the member II is located at the rear of said insulator. The members I1 and I! are fixed to the insulator I by elongated rods I9 which are: arranged at opposite sides of the insulator, said rods at their opposite ends being extended through socket elements formed on the members I1 and I8, and nuts 2| being mounted on the screwthreaded end portions of said rods and contacting with faces of said socket elements so as to draw the members l1 and I8 toward each other and securely clamp said members to the insulator I.

The member I1 is shaped in side elevation as is shown in Fig. 2 and secured to said member II by means of a pivot pin 22 for pivotal swinging movement is an arm 23, said pivot pin being extended through openings formed through portions of said member I1 and portions of the lower part of the arm 23. The upper portion of the arm 23 is curved inwardly, as indicated at 24 in Fig. 2,'and the inner end of said inwardly curved upper end portion of said arm 23 is spaced from an adjacent portion of the annular flange 4 of the head member 3 to provide an air gap 25 between said parts. The pivot pin 22 which supports the arm 23 has arranged thereabout a torsional coil spring 26 whose opposite end portions respectively engage a portion of the arm 23 and a portion of the member I'I whereby said torsional coil spring tends to maintain the arm 23 in the position in which it is shown by full lines in Fig. 2. Also, the arm 23 has formed therethrough a screwthreaded opening through which is screwthreadedly extended the shank of a headed adjusting bolt 21, the end of said bolt shank remote from the head of the bolt abutting against an upwardly projected extension I1 formed on the member I1. The bolt 21 serve as a stop element which maintains the setting of the gap 25, and also said bolt may be adlusted, in an obvious manner, so as to increase or decrease the width of said gap 25.

The member I8 is provided with a, portion I8 to which a line wire L is mechanically and electrically secured by means of a suitable connector 20. Likewise, the ground terminal I is provided with an extension I to which is mechanicall and electrically connected, with the aid of a sditable connector 29, a ground wire G. The insulator I has attached thereto a suitable hanger which serves as means for mounting the surge arrester A on a cross arm, or other support.

In the operation of the improved surge arrester disclosed herein the path of the surge current is by way of the line wire L to the member I8 and across to the member II by way of the rods I8 to and through the arm 23 and across the air gap 25 to the head member 3. From the head member 3 the surge current moves downwardly of the electrode I4 and across the internal gap I8 within the fiber tube I2 to the ground terminal I. The current passing along the arm 23 in one direction and along the electrode I in the opposite direction sets up opposing magnetic fields which tend to move the arm 23 outwardly to an outwardly displaced position. as indicated by dotted lines in Fig. 2. Thn action increases the width of the gap 25; and assists in extinguishing the are playingacross said gap, and after the surge has passed the torsional coil spring '28 returns the arm 23 to its normal'setting, as shown by full lines in Fig. 2. The prime function of the air gap 25 is to keep potential ofl of the surge arrester under normal conditions, while the function of the internal gap is is to extinguish the are created thereacross under surge conditions by subjecting said are to the arc-extinguishing efiect of gas given oif by the horn fiber tubular element I2 in the presence of the heat or the arc.

From the foregoing it is plain that the pivotally supported arm 23 of the surge arrester A may adjust itself in response to electrical force set up by passage of surge current through the surge arrester to increase the width of the air gap 25. and will return to its original position to reestablish the original setting of said air gap after the surge has passed. Thus, there is no permanent altering oi the width of the air gap 25 as a result of passage of surge current thereacross.

as was frequently the case heretofore when an arm corresponding to the arm 22 was mounted in a fixed position with respect toa member corresponding to the head member 3.-

We claim:

1. An electrical surge arrester comprising a hollow insulator, a member formed of electrical conductive material supported by said insulator at an end thereof,'a structure supported by said insulator and provided with means for connectmg a line wire to said structure, an arm movably supported by said structure and having a portion thereof spaced from a portion of said member to provide an external air gap therebetween, a second member formed of electrical conductive material which is supported by said insulator in spaced relation with respect to the first-mentioned member at the opposite end thereof, means for connecting a ground wire to said second memher, and an electrode connected to the first-mentioned member and disposed within said insulator in a manner to provide an internal arc gap within said insulator between a portion of said electrode and said second member, said arm and said electrode being so arranged in the surge arrester structure that current passes along the arm in one direction and along the electrode in the opposite direction whereby opposing magnetic fields are set up which tend to move the arm to an outwardly displaced position with respect to said member so as to increase the gap between said arm and said member.

2. An electrical surge arrester comprising a hollow insulator, a member formed of electrical conductive material supported by said insulator at an end thereof, a structure supported by said insulator and provided with means for connecting a line wire to said structure. an arm pivotally supported by said structure and having a portion thereof spaced from a portion of said member to provide an external air gap therebetween, a second member formed of electrical conductive material which is supported by said insulator in spaced relation with respect to the first-mentioned member at the opposite end thereof, means for connecting a ground wire to said second mem-- ber, and an electrode connected to the first-men tioned member and disposed within said insu later in a manner to.provide an internal arc gap within said insulator between a portion of saidelectrode and said second member, said arm and it said electrode being so arranged in the surge arrester structure that current passes along the arm in one direction and along the electrode in the opposite direction whereby opposing magnetic fields are set up which tend to move the arm tr. an outwardly displaced position with respect to said member so as to increase the gap between said arm and said member.

3. An electrical surge arrester comprising a hollow insulator, a member formed of electrical conductive material supported by said insulator at an end thereof, a structure supported by said insulator and provided with means for connecting a line wire to said structure, an arm pivotally supported by said structure and having a portion thereof spaced from a portion of said member to provide an external air gap therebetween, spring meansfor returning said pivotally supported arm to its normal position when it has been moved from said normal position, a second member formed of electrical conductive material which is supported by said insulator in spaced relation with respect to the first-mentioned member at the opposite end thereof, means for connecting a ground wire to said second member, and an electrode connected to the first mentioned member and disposed within said insulator in a manner to provide an internal arc gap within said insulator between a portion of said electrode and said second member, said arm and said electrode being so arranged in the surge arrester structure that current passes along the arm in one direction and along the electrode in the opposite direction whereby opposing magnetic fields are set up which tend to move the arm to an outwardly displaced position with respect ,to said member soas to increase the gap between said arm and said member.

4. An electrical surge arrester comprising a hollow insulator, a member formed of electrical conductive material supported by said insulator at an end thereof, a structure supported by said insulator and provided with means for connecting a line wire to said structure, an arm pivotally supported by said structure and having a portion thereof spaced from a portion of said member to provide an external air gap therebetween, torsional spring means for returning said pivotally supported arm to its normal position when it has been moved from said normal position, a second member formed of electrical conductive material which is supported by said insulator in spaced relation with respect to the first-mentioned mem- Ber at the opposite end thereof, means for connecting a ground wire to said second member, and an electrode connected to the first-mentioned member and disposed within said insulator in a manner to provide an internal arc gap within said insulator between a portion of said electrode and said second member, said arm and said electrode tion and along the electrode in tne opposite direction whereby opposing magnetic fields are set up which tend to move the arm to an outwardly displaced position with respect to said member so as to increase the gap between said arm and said member.

5. An electrical surge arrester comprising a hollow insulator, a member formed of electrical conductive material supported by said insulator at an end thereof, a structure supported by said insulator and provided with means for connecting a line wire to said structure, an arm pivotally supported by said structure and having a portion thereof spaced from a portion of said member to provide an external air gap therebetween, means for returning said pivotally supported arm to its normal position when it has been moved from said normal position, adjustable means comprising a screwthreaded element supported by said arm and adapted to abut against a part of said structure for establishing and maintaining the normal position of said arm, a second member formed of electrical conductive material which is supported by said insulator in spaced relation with respect to the first-mentioned member at the opposite end thereof, means for connecting a ground wire to said second member, and an electrode connected to the first-mentioned member and disposed within said insulator in a manner to provide an internal arc gap within said insulator between a portion of said electrode and said second member, said arm and said electrode being so arranged in the surge arrester structure that current passes along the arm in one directhat current passes along the arm in one direction and along the electrode in the opposite direction whereby opposing magnetic fields are set up which tend to move the arm to an outwardly displaced position with respect to said member so as to increase the gap between said arm and said member.

LINDELL LLOYD CRUMP.

CHARLES ADIN FOX.

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

UNITED STATES PATENTS Number Name Date 1,197,485 Heinritz Sept. 5, 1916 2,108,465 Austin Feb. 15, 1938 2,169,110 Pittman Aug. 8, 1939 2,177,744 Pittman Oct. 31, 1939 2,296,621 Wade Sept. 22. 1942 2,338,479 Ackermann Jan. 4, 1944 2,427,460 Johnson Sept. 16, 1947 FOREIGN PATENTS Number Country Date 543,571 Great Britain Mar. 4, 1942

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