US2593393A - Lightning protector device - Google Patents

Description

April 1952 R. D. NELSON ET AL LIGHTNING PROTECTOR DEVICE 2 SHEETS-SHEET 1 Filed Nov. 22, 1950 INVENTORS. Fa/kwvdfl Ne/son By 54w? A. L/n/r ATTORNEY April 15, 1952 Filed Nov. 22, 1950 R. D. NELSQN El AL LIGHTNING PROTECTOR DEVICE 2 SHEETS--SHEET 2 Patented Apr. 15, 1952 2,593,393 LIGHTNING PROTECTOR DEVICE Rolland D. Nelson, Hales Corners, and Edwin A. Link, Milwaukee, Wis., assignors to Rural Transformer & Equipment 00., Milwaukee, Wis., a corporation of'Illinois Application November 22, 1950, Serial N 0. 197,002

12 Claims.

This invention relates to lightning protectors for electrical instrumentalities, such as transformers and other electrical equipment, and more particularly to that type of protector device having a double gap.

.In providing lightning protection for electrical instrumentalities, such as transformers and other equipment, it has been common practice to install a protector device between the power line and the primary winding of the transformer, or the load line in the case of other equipment. The general purpose of all of these protector devices is to prevent damage to the protected equipment and to provide a device which will prevent the unnecessary blowing of fuse devices under the influence of current surges incident to flashes of lightning or other causes. Practically all of the double gap lightning protector devices, now in common use, are composed of two or more parts which are independently mounted necessitating separate mounting and adjustment of each part in order to establish the desired distance between the elements which form the spark gaps. In addition to requiring greater time in mounting and adjusting protective devices of this type, it has been found that accidental displacement of one or the other elements forming the spark gaps is not an infrequent occurrence with the result that the effective protective qualities of the devices may be greatly impaired due to the improper spacing of the spark gaps.

This invention is designed to overcome the above noted defect by providing a new and improved lightning protector of the double gap type which comprises a unitary structure having a single adjustable mounting means-adapted for ready application to existing equipment.

The primary object of the present invention resides in the provision of a new and improved series arranged double gap lightning protector device in the form of a unitary structure adapted for ready application to existing equipment and incorporating a single adjusting means for establishing a proper gap setting at the time the device is installed.

Another object of the present invention resides in the provision of a new and improved lightning protector device in the form of a selfcontained unitary structure providing excep tional protection against accidental shorting under the'infiuence of birds, animals, reptiles, insects, or even ice formation.

Another object of the present invention resides in the provision of a new and improved lightning protector device having simple and sturdy construction and adapted to be manufactured inexpensively.

A further object of the invention lies in the provision of a new and improved mounting bracket for securing the device on the marginal flanged portion of a transformer tank cover.

A still further object lies in the provision of means associated with the mounting bracket of the device for insuring its retention in proper vertical position.

Other objects and advantages will become apparent from the following description of illustrative embodiments of the invention.

:In the drawings:

Figure 1 is an elevational view showing a lightning protector device constructed in accordance with the teachings of the present invention and adapted for mounting upon a conventional cross arm bracket;

Fig. 2 is an enlarged view, partly in section, showing the construction of the lightning protector device and illustrating .the means for adjustably positioning the same on a cross arm mounting bracket;

Fig. 3 is a vertical sectional view, taken on the line 3-3 of Fig. 2 and showing a means for retaining the lightning protector device against angular movement on the mounting bracket;

, Fig. 4 is a bottom plan view of the lightning protector device shown in Fig. 2;

Fig. 5 is a view similar to Fig. 1 showing the protector device attached to a modified form of mounting bracket adapted to be mounted on the cover portion of a transformer tank;

Fig. 6 is a rear elevational view of the modified form of mounting bracket shown in Fig. 5; and

Fig 7-is a horizontal sectional view, taken on the line 1-! of Fig. 6, showing the association between an adjustable clamping member and the flanged portion of the transformer tank cover on which the mounting bracket is secured.

Referring more particularly to Fig. 1 of the accompanying drawings, it will be noted that the lightning protector device [0, chosen for illustrative purposes and embodying the teachings of the present invention, is mounted for adjustable positioning on an outwardly projecting horizontally disposed portion ll of a cross arm mounting bracket l2 to which conventional standoff insulators l3 are mounted in the usual manner, at right angles to each other. The vertically projecting standofi" insulator I3 is provided with the usual terminal casting l4, secured to its upp r end in the customary manner, which provides a mounting for a forked arm 15, or aterminal clamp whichever is desired and the chosen element may be drawn in the clamping engagement with the stripped end of a power line lead I6 by the tightening of a cap screw H. In the instance where the forked arm I is employed, the insulator I3 disposed in a horizontal plane is adapted to carrythe usual spring contact member (not shown) which cooperates with the forked arm I5 to provide a mounting means for the customary fuse link (not shown). The mounting bracket I2 is adaptedto be secured to a pole cross arm in the usual manner.

Referring more particularly to Fig. 2, it will be noted that a double gap lightning protector device Ifl, the gaps of which are arranged in series, comprises a hollow cylindrical insulating tube I8, preferably formed of porcelain, which serves as a housing for a conductor IS. The conductor I9 is preferably in the form of a bolt having its head portion positioned above and overlying the upper end of the insulating tube I8 and seated upon a fibre or insulating washer 20. The lower or threaded end of the conductor or bolt I9 projects below the lower extremity of the insulating tube I8 and the conductor I9 is retained in proper position within the tube I8 by the tightening of a nut 2] against another fibre washer 20, positioned between the nut H and the lower end of the tube I8.

From the foregoing description it will be seen that the insulating tube I8 encloses substantially the entire length of the conductor to provide adequate protection for the same; leaving only the head portion exposed at the top of the insulating tube and a short protruding end portion at the lower extremity of the tube I8. The insulating tube I8 is positioned and retained in a vertically disposed opening 22 extending through a projecting portion 23 of a supporting bracket 24 by the application of cement 25. The supporting bracket 24 includes a horizontally projecting fiat portion 26 provided with an elongated slot 21 adapted to receive the anchoring bolt of the vertically disposed insulator I3 and provide a means for adjustably positioning the lightning protector device III with respect to the insulator I3 to establish accurately the length of a gap A between the head of the conductor I9 and a flanged portion 28 of the terminal casting I4 prior to the tightening of a nut 29 applied to the anchoring bolt of the insulator I3 to releasably retain the insulator I3, the supporting bracket 24, and the cross arm mounting bracket I2 in fixed associated position: The supporting bracket 24 is further provided with a depending flanged portion 30 having a surface 3| disposed in parallel relationship with the insulating tube I8 and projecting below the lower extremity of the tube to form a gap B, having a fixed length, between the lower extremity of the conductor I9 and the surface 3| on the portion 30 of the supporting bracket 24.

The mounting bracket I2 (see Fig. 1) is provided with a ground connector 33 adapted to establish an electrical connection between the lightning protector device It) and the ground through the medium of a conductor or ground -respect to the surface of the flanged portion 28 "of the-terminal casting I'4' so as to establish, with accuracy, the length of the spark gap A. Under normal conditions, it is desirable to establish the length of the spark gap A at approximately one and one-eight inches for a transformer having 7500 volt class insulation. It will be noted that the length of the spark gap B is maintained fixed at all times. This distance is approximately one-half inch for the above mentioned insulating rating, which distance has been found suiucient to prevent line voltage spark- Referring to Fig. 3, it will be noted that the lightning protector device I0 is retained against accidental displacement or sideward movement with respect to the mounting bracket I2 by the cooperating relationship established between a depending flanged portion 32 formed on the projecting portion 23 of the supporting bracket 24 with one side of the horizontally disposed upper end portion of the cross arm mounting bracket I2.

Referring more .particularly to Fig. 5 of the accompanying drawings, it will be noted that the lightning protector device I9 is identical in all respects with that previously described. However, it will be noted that a modified form of mountingbracket has been provided; adapted toafford a means for positioning the lightning protector device I0 upon the cover of a transformer tank. The modified form of mounting bracket includes a body portion 35 having a horizontally disposed upper end portion 36 provided with a hole to receive the anchoring bolt of the insulator l3, which bolt also provides the means for anchoring the supporting bracket 24 in desired position of adjustment to establish the desired length of spark gap A between the upper exposed end of the conductor I9 and the flanged portion 28 of the terminal casting I4. The lower portion of the modified form of mounting bracket includes a horizontally extended portion 31 terminating in a downwardly directed end portion 38. A clamping member 39 is slidably receivable on the end portion 38 of the mounting bracket and a bolt 40 passing through a hole M in the horizontal portion 31 of the bracket and having threaded engagement with a hole in a boss 42 formed on the clamping member 39 provides the means for adjusting the position of the clamping member 39 on the mounting bracket. It will be noted that the clamping member 39 is provided with a pair of guide lugs 43 adapted to cooperate with the surface of the portion 38 of the mounting bracket to insure smooth running of the clamping member 39 on the mounting bracket and prevent a canting or binding movement of the clamp under the action of the tightening bolt 40 when the clamp is in gripping position. The clamping member 39 is further provided with an upwardly directed arcuate flange portion 44 adapted to lie between the outer surface of a transformer tank wall 45 and the inner surface of a depending marginal flange 46 formed on a transformer tank cover 4'1.

In practice, the mounting bracket is properly positioned on the marginal portion of the transformer tank cover 41 with the bottom surface of the portion 31 of the mounting bracket in contact with the top of the cover 4'! and the depending end portion 38 spaced from the outer surface of the tank wall 45. The bolt 49 is then tightened to draw the clamping member 39 into contact with the bottom edge of the marginal flange 46 'onthe tank cover with the arcuate flange 44 on the clamping member 39 disposed'behindthe flange 46. When the clamping member 39 is tight adapted to exert pressure against the wall of the tank to draw the flange 44 into contact with the inner surface of the marginal flange 46 of the tank cover and effect a rocking action of the mounting bracket to bring it into proper position, with the standoff insulator in vertical position. After the proper adjustment of the bolt 48, a pair of jam nuts 50 disposed at opposite sides of the portion 38 of the bracket are drawn into contact with the surface of the mounting bracket to releasably retain it in proper position. After the mounting bracket is thus properly positioned,'the bolt 40 may be tightened to insure firm anchorage of the entire lightning protector assembly on the cover of the transformer tank.

'A brief description of the operation of the lightning protector device will serve to emphasize the several advantages of the present invention. At the outset, it should be noted that the present lightning protector I0 is a series arranged double gap device of unitary construction adapted for adjustable mounting on a support to provide a simple and effective means for establishing the proper or desired length of the spark gap A between the upper exposed portion of the conductor I9 and the flanged portion 28 of the terminal casting M to which the power line lead I6 is connected. In the event of current surges in the power line due to lightning or other causes, the high voltage current will jump the gap A, travel down the conductor [9, jump the spark gap fB which is in series arrangement with the spark gap A and continue through the supporting bracket 24, the mounting bracket l2, the connector 33 and to'the ground through the ground "wire 34 to dissipate the high voltage current surge I without causing damage to the protected equipment or blowing protective fuses between the While the embodiments of the double gap lightning protector herein shown and described represent-preferred forms of the invention, it is to be understood that the invention is predicated, primarily, upon the unitary structure of the device combined with a single mounting means therefor.

Obviously, where the lightning protector device is designed for separate use with a number of individual voltage devices having similar or substantially identical characteristics, the adjustable feature of the supporting member on a mounting means may be eliminated. By the same token, 'it'is also immaterial whether the lightning protector device is mounted on the power line or upon a suitable ground connection; since the device includes a conductor having a pair of extremities which are respectively adapted to co- I operate with a live portion of the power line and a ground connection. While the device shown in the illustrative embodiments includes a fixed 'gap B .it is .tobe understood that any suitable means'may be incorporated in the device for adjusting the fixed length of the gap to suit the same for specific requirements of the particular circuit which it is designed to protect. In like manner, where it is desirable to provide means for adjusting the relative position of one of the exposed portions of the conductor with respect to the cooperating portion of the circuit to estab lish a spark gap of desired and proper length, it is immaterial whether this spark gap is established between the power line and one extremity of the conductor or the other extremity of the conductor and the ground connection.

From the foregoing description of illustrative embodiments of the present invention, it will'be apparent that a new and improved series arranged double gap lightning protector has been provided which is adapted for ready application to existing equipment, is simple in construction and is effective in operation.

It should be noted that the series arranged double gap lightning protector of the present invention is unitary in construction and hence materially reduces both the time of efiectin'g its installation and proper adjustment for effective operation.

It should also be noted that the double gap lightning protector includes one spark gap of fixed length while the positioning of the device is readily adjustable to establish the proper length of the second series arranged gap of the device.

It should further be noted that a new and improved mounting bracket has been provided adapted for application to a standard transformer tank cover to permit ready application of the lightning protector to the transformer if this positioning be desired.

A. more detailed advantage of the present device is found in the provision of means for insuring the desired upright position of the device by providing adjusting means adapted to be manipulated to adjust the position of the device on the cover of a transformer tank.

While the invention has been described in considerable detail in the foregoing specification, it is to be understood that various changes may be made in its embodiments without departing from or sacrificing any of the advantages hereinafter claimed.

We claim:

1. A double gap lightning protector for electrical instrumentalities, said protector comprising a hollow element formed of insulating material, a conductor disposed Within said hollow element, said conductor having exposed portions projecting beyond the confines of said hollow element at remote portions thereof, and a supporting member of said element, each of said exposed portions of said conductor forming one terminal of a pair of spaced series arranged spark gaps, one of said exposed portions of said conductor cooperating with a ground connection to form one gap and the other 01" said exposed portions cooperating with a live portion of a power line to form the other gap, whereby a series arranged double gap lightning protector is provided having a single mounting means and affording protection against accidental shorting through contact of foreign bodies by reason of its construction.

2. A double gap lightning protector for electrical instrumentalities, said protector comprising a unitary structure for positioning on a mounting means, said-structure including a hollow element formed of insulatin material, a conductor disposed within said hollow element, said conductor having exposed portions projecting beyond the confines of said hollow element at remote portions thereof, and a supporting member for said element, each of said exposed portions of said conductor forming one terminal of a pair of spaced series arranged spark gaps separated by said hollow element, one'of said exposed portions of said conductor cooperating with a ground connection to form one gap and the other of said exposed portions cooperating with a live portion of a power line to form the other gap, whereby a unitary series arranged double gap lightning protector is provided having a single mounting means and affording protection against accidental shorting by reason of its construction.

3. A double gap lightning protector for electrical instrumentalities, said protector comprising a hollow tubular element formed of insulating material, a conductor axially disposed within said hollow tubular element, said conductor having exposed portions projecting beyond the ends of i said hollow tubular element, and a supporting member for said element, each of said exposed portions of said conductor forming a terminal of a pair of spaced series arranged spark gaps, one of said exposed portions of said conductor cooperating with a ground "connection to form one gap and the other of said exposed portions of said conductor cooperating with a live portion of a power line to form the other gap, whereby a series arranged double gap lightning protector is provided having a single mounting means to facilitate its positioning and providing a device aiiording protection against accidental shorting by reason of its construction.

4. A double gap lightning. protector for electrical instrumentalities, said protector comprising a unitary structure for positioning on a mountin means, said structure including a hollow tubular element formed of insulating material, a conductor axially disposed withm said tubular element, said conductor having exposed portions projecting beyond the ends of said tubular ele ment, and a supporting member for said element, each of said exposed portions of said conductor forming one terminal of a pair of spaced series arranged spark gaps, one of said exposed portions of said conductor cooperating with a ground connection to form one gap and the other of said exposed portions cooperating with a live portion of a power line to form the other gap, whereby a unitary series arranged double gap lightning protector is provided having a single mounting means and affording protection against accidental shorting by reason of its construction. 5. A double gap lightning protector for electrical instrumentalities, said protector comprising a tubular element formed of insulating material, a conductor axially disposed within said tubular element, said conductor having exposed portions projecting beyond the ends of said tubular element, a supporting member for said element, and anchoring means for adjustable positioning said supporting member on a mounting means, each of said exposed portions of said conductor forming one terminal of a pair of spaced series arranged spark gaps, one of said exposed portions of said conductor cooperating with a ground connection to form one gap and the other of said exposed portions arranged to cooperate with a live portion of a power line to form the other gap, the length of one of saidgaps being adjustable in accordance with the positioning'oi said supporting member with respect to the mounting means to which it-is secured.

6. A double gap lightning protector for electrical instrumentalities, said protector comprisin a unitary structure for adjustable positioning on a mounting means, said structure including a tubular element formed of insulating material, a conductor axially disposed within said tubular element, said conductor having exposed portions projecting beyond the ends of said tubular element, and a supporting member for said tubular element, each of said exposed portions of said conductor forming one terminal of a pair of spark gaps arranged in series, one of said exposed portions of said conductor cooperating with a ground connection to form one gap and the other of said exposed portions cooperating with a live portion of a power line to form the other gap, the length of one of said gaps being adjustable in accordance with the positioning of said unitary structure with respect to the mounting means to which it is secured.

'7. A series arranged double gap lightning protector for electrical instrumentalities, said protector comprising a tubular element formed of insulating material, a conductor axially disposed within said tubular element, said conductor having exposed portions projecting beyond the ends of said tubular element, a supporting member for said element including a portion having an aperture therein for receiving said element, and securing means for retaining said element in said supporting member, said supporting member also including a projecting portion for adjustable positioning on a mounting means to which it is secured, one of said exposed portions of said conductor cooperating with a grounded conductor to form one spark gap and the other of said exposed portions of said conductor cooperating with a live portion of a power line to form the other of said series arranged spark gaps, the length of one of said gaps being adjustable in accordance with the positioning of said supporting member with respect to the mounting means to which it is secured.

8. A series arranged double gap lightning protector for electrical instrumentalities, said protector comprising a unitary structure for adjustable positioning on a mounting means, said structure including a tubular element formed of insulating material, a conductor axially disposed within said tubular element and having its extremities projecting beyond the ends of said tubular element, a supporting member for said element including an element receiving portion and a mounting portion, one of said projecting extremities of said conductor cooperating with a grounded conductor to form one spark gap and the other of said projecting extremities cooperating with a live portion of a power line toform the other spark gap, the length of one of said spark gaps being in accordance with the adjusted positioning of the mounting portion of said supporting member with respect to the mounting means to which it is secured.

9. A series arranged double gap lightning protector for electrical instrumentalities, said protector comprising a tubular element formed of insulating material, a conductor axially disposed within said tubular element and having its extremities projecting beyond the ends of said element, a supporting member for said element, anchoring means for adjustably positioning said supporting member on a mounting'means, and a surface on said supporting member disposed in fixed relationship with one extremity of said conductor to form a spark gap having a fixed length, the other extremity of said conductor cooperating with a live portion of a power line to form the other spark gap, the length of said last named gap being adjustable in accordance with the positioning of said supporting member with respect to the mounting means to which it is secured.

10. A series arranged double gap lightning protector for electrical instrumentalities, said protector comprising a unitary structure for adjustable positioning on a mounting means, said structure including a tubular element formed of insulating material, a conductor axially disposed within said tubular element and having its ex tremities projecting beyond the ends of saidtubular element, a supporting member for said element including a mounting portion, and a surface on said supporting member disposed infixed spaced relationship with one extremity of said conductor to form a spark gap having a fixed length, the other of said extremities of said conductor cooperating with a live portion of a power line to form the other spark gap, the length of said last named spark gap being adjustable in accordance with the positioning of said mounting portion of said supporting member with respect to the mounting means to which it is secured.

11. A double gap lightning protector for electrical instrumentalities, said device comprising a tubular element formed of insulating material, a conductor axially disposed within said tubular element and having its extremities exposed beyond the ends of said tubular element, a supporting member for said element, a mounting bracket for said supporting member, adjustable means for altering the relative position of said supporting member with respect to said mounting bracket, and an adjustable clamping member on said mounting bracket cooperating with a portion of said mounting bracket to form a gripping device for positioning and releasably retaining said lightning protector on the flanged portion of a transformer tank cover, one of said exposed extremities of said conductor cooperating with a grounded conductor to form one spark gap and the other exposed extremity of said conductor cooperating with a live portion of a power line to form the other spark gap.

12. A series arranged double gap lightning protector for electrical instrumentalities, said protector comprising a unitary structure for mounting on a bracket, said structure including a tu bular element formed of insulating material, a conductor disposed within said tubular element and having its extremities exposed beyond the ends of said tubular element, a supporting member for said element, a mounting bracket for said supporting member, and an adjustably mounted clamping member on said mounting bracket co operating with a portion of said bracket to form a gripping device for positioning and releasably retaining said lightning protector on the flanged portion of a transformer tank cover, one of said exposed extremities of said conductor cooperating with a grounded conductor to form one spark gap and the other exposed extremity of said conductor cooperating with a live portion of a power line to form the other spark gap of the lightning protector.

ROLLAND D. NELSON. EDWIN A. LINK.

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

UNITED STATES PATENTS Number Name Date 2,003,298 Lemmon June 4, 1935 2,018,672 Hill Oct. 29, 1935

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