US2209823A - Fuse - Google Patents

Description

July 30, 1940. I K. A. LOHAUSEN FUSE Filed Dec. 7. 1937 2 Sheets-Sheet 1 Fig. L

Inventor; Karl A. Lohausen,

by )V His Attorney.

July 30, 1940. K. A. LOHAUSEN 2.209.823

- FUSE" Filed Dec. 7, 1937 2 Sheets-Sheet 2 Pig. 8.

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b X :A Attorney Patented July 1940 I v UNITED, STATES PATENT OFFICE FUSE Karl A. Lohausen, oberschoneweide, Germany, assignor to General Electric Company, a cor-. poration of New York Application December 7, 1937, Serial No. 178,608 In Germany December 16, 1936 13 Claims. (or zoo-12o) The present invention relates to fuses, and I Thus, the metal vapor ions are absorbed so that more particularly to fuses of the current limitthe current is obliged to flow through the suring type wherein a fusible element is embedded rounding fused filling material and the arcs are in a granular, arc-quenching material. more q y extinflllshed than would e the An important object of the invention is the case if the conductors extended substantially 5 provision of an improved high voltage fuse for in a straight line or without the frequent changes the interruption of very large currents, which in direction afforded by the zigzag arrangement. fuse is, of the type wherein a fusible element is My present invention has, therefore, as a furembedded in a granular, inert, arc-quenching ther andmore specific object, the provision of materlal'such as sand or pulverized quartz. an improved fuse construction for effecting in 10 When a fuse of the type referred to in the prea practical and economical manner the desirable ceding paragraph is subjected to current of sufarrangements discussed in the preceding paraficient magnitude, the'fusible element fuses and graph. vaporizes with accompanying formation of an Qther objects and that which I believe to be 1 5 are along the path of the element, and the heat novel and my invention will become apparent 115 and vapors of the are are dissipated through the from the following description and the claims surrounding granular, inert, arc-quenching ma= appended thereto taken in conjunction-with the terial. I have found that the heat of the arc accompanying drawings in which are illustrated causes fusion of the immediately surrounding exemplary fuse constructions embodying my body of material and that subsequently this fused present invention. In the drawings, Fig. 1 shows 90 mass solidifies into a more or less rigid shell surin cross-section a part of one of the exemplary rounding the space previously occupied by the fuse constructions; Fig. 2 shows in perspective fusible element. This shell will be designated a part of a supporting structure for use in the hereinafter as the fusion shell." Although not fuse of Fig. 1; Fig. 3 is a plan view of an element 5 fully understood, it is believed that the current adapted for use as a part of the suppoi ting strucg5 limiting action of this type of fuse is due to the ture of Fig. 2; Fig. 4 is a detail plan view of a transfer of the current from the arc to the importion of the element of Fig. 3; Fig. 5 illusmediately surrounding mass of fused inert filling trates a modification of the element of Figs. 3 material, the conductivity of which'is greatly'inand 4; Figs. 6 and '7 illustrate two methods of creased upon fusion, with resultant dying out of assembly of the-supporting structure of Fig. 2; 30

the arc and resolidification of the fused mass, Fig. 8 illustrates diagrammatically a longitudiwhereupon the material of the solidified fusion nal cross-section of a modified form of supportshell again has the high resistance value of an ing structure for use in the practice of my inveninsulator and interrupts the fiow of current tion; Fig. 9 is a view looking down on the. top of therethrough. the structure of Fig. 8 with certain of the ele- 3 I have found it advantageous in the construcments removed for clarity; Fig. 10 is a perspection of fuses of the type, above referred to for tive view of a portion of an element of the supinterruption of extremely high currents, to subporting structure cf Fig. 8; Fig. 11 illustrates diadivide the fusible element into a large number of grammatically a longitudinal cross-section of parallel connected very fine wire conductors so another fornrof supporting structure for carryas greatly to.increase'the conductor surface in Y ing out my invention; and Fig. 12 shows in percontact with the granular, inert, filling material, spective one of the elements of the supporting Thisgreatly facilitates the dissipation-of the are structure of Fig. 11. In the interests of clarity, energy. I have found it advantageous also to the various constructions are illustrated someprovide a zigzag arrangement of the conductors what diagrammatically in the several figures so that the conductors sharply change their diand the relative sizes and spacings of the various rections' at frequent intervals along their lengths. parts are somewhat exaggerated. The metal vapor ions developed upon fusion and Y The fuse of Fig. l is providedwith an enclosing vaporization of the conductors are accelerated in casing ll of suitable insulation material having 1 the direction of the electric field and; due to the a metal end cap II which is secured to the casing so zigzag arrangement, are projected against the by self-threading screws II or other suitable walls of the channels in the filling material means and which has a cylindrical boss I! for through which the conductors pass,.these-walls connection and mounting purposes. The casing in the zigzag arrangement being perpendicular is filled with a body ll of finely divided, or granor oblique to the direction of the electric field. ular, inert, arc-quenching material such as sand, .5

pulverized quartz, or the like,'and embedded in this filling material are a large number of fine wire fusible conductors l5 carried by a supporting'structure of the type shown in perspective in- Fig. 2. This supporting structure consists in the :main of a plurality of transverse disks l6 arranged in parallel extending spaced apart relationship. These disks are comprised of non-inflammable, high melting point, non-arcing, and preferably ceramic, insulating material. The positioning of the disks-may be maintained in either of the two manners illustrated in Figs. 6 and 7. In the construction of Fig. 6*, each of the disks I6 is provided with an integrally formed and centrally located'hollow supporting and spacing tube |1. Each of the disks has also a beveled seat I 8 formed on the opposite side thereof from its 'tube l1, whichseat is adapted to receive the beveled end of the tube l1 of the next adjacent disk. Any desired number of units, each comprised of ,a disk It and its integrally formed tube '|1,.may be secured end to end, by cementing or other suitable method, to provide ,a supporting structure of any desired length. when the supporting structure is mounted within casing |0, there may be provided end disks l9 which have tubular, bosses 20' adapted to fit in hollow bosses 2| of metal terminal plates 22, one

of which is shown in the drawings. 'As shown in Fig. 1, the boss 2| of the terminal plate 22 fits into the terminal boss l3 of end cap so as to maintain the positioning of the supporting structure, while the terminal plate extends outwardly over the surface of the end disk Is to contact with the ends of the fusible conductors l5 and also extends into engagement with the inner. walls of casing 10 to aid in-maintaining the supporting structure in proper position.

In the construction of'Fig'. 7, the disks l6 are mounted on a hollow tube 25 which extends through centrally located openings in the disks, and the disks are held in properly spaced apart relation by spacing tubes 26 disposed concentrically of tube 25. Tubes 25 and 26 may be of either the same or similar material to that employed in the construction of disks IS. The method of assembly of Fig. 7 may be utilized to --l secure additional strength and rigidity of support but lacks the advantage of providing for the assembly of any desired number of units, as is possible with the construction of Fig. 6. The supporting structure assembled in accordance with Fig. 'I may be mounted in the enclosing casing III in the same manner as that described in the preceding paragraph in connection with the structure of Fig. 6.

Around the peripheries of the disks l6 are formed a large number of-notches 21 for receivingthe wire conductors IS. The individual conductors preferably have a diameter in the order of magnitude of 0.1 to 0.3 millimeter. In order to produce a large number of sharp changes of direction of the conductors, they are arranged on the supporting structure in zigzag formation so that they sharply change their directions at each of the .points of engagement with the notches 21 of the successive disks l6. Notches 21 are arranged so as to maintain the conductors in parallel extending relationship in an imaginary cylindrical surface with the conductors uniformly spaced apart approximately the thickness of a fusion shell. I do not wish to be limited to any specific spacing since I have found that the thickness of the fusion shells varies as a function of the current interrupted and they may attain a thickness of approximately 3.18

millimeters. It is possible for one skilled in the art to determine by experimentation the fusion shell thickness to be expected and thereby the proper spacing, in the practice of the present invention, for any particular fuse, which spaci n g will depend upon the current value which the fuse is designed to interrupt. Also, the number of fusible conductors employed depends upon the operating current, but it is desirable for most efl'ective results on fuse operation that the individual conductors be limited to a diameter not greatly exceeding the upper limit given above.

By the arrangement of the conductors as above .of fusible conductors arranged in an imaginary cylindrical surface disposed concentrically within the imaginary cylindrical surface occupied by the outer set of conductors, as indicated in Fig, 3. Also, disks It may be provided, as indicated in Fig. 5, with projections 3|, instead of the notches 21, for positioning the outer set of fusible conductors, and may be provided also with inwardly spaced openings 32 instead of the deep slots 3|] for receiving an inner set of fusible conductors. Although disks l6-are illustrated as being circular, they may if desired be given an oval, rectangular, or other suitable shape in accordance with the shape of the particular enclosing casing employed. Moreover, the space withinthe hollow tubes H or 2 5 may be employed to accommodate a high resistance wire 33,- con- I nected in parallel with the fusible conductors, j as is sometimes desired.

The fusesupporting structure illustrated in Figs. 8 and 10 is adapted tobe accommodated in arectangular enclosing casing and to be used where it is desired to employ a very large number of parallel connected fusible wire conductors. This supporting structure is comprised of a plurality of ladder-like frames 35 adapted to extend lengthwise of the enclosing casingand to be held in parallel side by side relation by means of a suitable framework. 36. As will be seen from Fig. 10, each of the frames 35 is comprised of a pair of side members 40,;of zigzag form, held in spaced apart relationship by means of insulating cross-bars 4|. The successive cross-bars 4| are staggered laterally of the frame so as to support'the conductors I5 in zigzag arrangement, as shown in Fig. v8. In the final number of fusible conductors with the conductors maintained in closely spaced, parallel extending relationship and with the individual conductors changing their .direction at frequent intervals along the lengths thereof.- Cross-bars 4| may be provided with any suitable means for maintaining the conductors in properly spaced relation- I tanceapproximately equal to ship, the spacing, as previously pointed out, being approximately the thickness of a fusion shell where, in the, final assembly, the fusible conductors are embedded in finely divided, or granular, inert, arc-quenching material, asin the em-' bodiment of Fig. 1:

In the modified structure of Fig. 11, the conductors l5 are positioned by frames 45 adapted to extend transversely of an enclosing casing and to be held in parallel side by side relationship by means of a suitable framework 46. As will be seen from Fig. 12, each of the frames 45 is comprised of a pair of side members '41 which are held in spaced relationship by insulating cross-bars". In the assembly of frames 45 in the framework 46, the frames are so arranged that cross-bars 48 of the successive frames are laterally staggered relative to the longitudinal axis of the framework so as to provide a zigzag arrangement of conductors I5, as shown in Fig.

11. Thus, in the final assembly, the arrangement of the conductors is the same as that af-' forded by the supporting structure of Fig. 8 and the ends of the conductors are connected'to terminal plates 42, as previously pointed out. With the arrangements of both Figs. 8-and 111, the conductors are maintained in a plurality of groups with the conductors of each group extending in closely spaced zigzag parallel relationship in an imaginary plane surface.

High voltage fuses constructed in accordance with my present invention as hereinbefore set forth are capable of interrupting satisfactorily currents of extremely large magnitude due to the large number of fine wire conductors and the effective zigzag arrangement of the conduc tors, while at the same time-being of very compact, practical, and economical construction. Moreover, as will be evident to one skilled in the art, the invention in certain ofits aspectsis not limited to the particular details ofthe exemplary embodiments illustrated. and it is intended, therefore, that the appended claims shall I cover such modifications or as do not depart from t of the invention.

What I claim as new anddesire to obtain by Letters Patent of the United States is:

1. In a fuse device including a body of granular, inert, arc-quenching material, a large number of fine wire fusible conductors connected electrically other applications e true spirit and scope in parallel and extending through and embedded in saidmaterial, and an insulating structure for supportingsaid wires with the wires extending longitudinally of the supporting structure, which said structure engages said wires only at points spaced apart substantial distances along the lengths of the wires ina manner to maintain a longitudinally zigzagging arrangement of the wires and to maintain adjacent ones of the wires substantially uniformly spaced apart at a. disthe thickness of a fusion shell formed in said material upon fuse operation in the mannerdescribed.

2. In a fuse device including a body of inert, arc-quenching material, a large-number of fine wire fusible conductors connected electrially in parallel and extending through and embedded in said material, each of saidwlres having a diameter in the order of 0.3 mm. or less, and an insulating structure for supporting said wires with the wires-extending longitudinally of the supporting structure, which said structure engages the wires only at points spaced apart substantial distances along lengths of thewires granular,

in a manner to maintain the wires in a longitudinally zigzagging arrangement with adjacent ones of the wires substantially uniformly spaced apart at a distance approximately equal to the thickness of a fusion shell formed in said maments also being arranged to maintain a substantially uniform spacing in said surface between adjacent ones of said wires.

4. In a fuse device, the combination of a large number of fuse wires, spaced terminal means therefor, an insulating structure supporting said wires with the wires extending generally longitudinally of the supporting structure, which structure includes a plurality of disk-like elements extending transversely of the supporting structure in substantially parallel relationship and located respectively at intervals spaced longitudinally of the supporting structure, said disk-like elements engaging said wires at points spaced apart along the .lengths of the wires in a manner tomaintain the wires in zigzagging courses with a substan- .the central longitudinal axis tially uniform spacing between adjacent ones of the wires, and granular arc-quenching material surroundingand embedding said wires throughout the major portion of the lengths of the wires.

5. In a fuse device, the combination of a multiplicity of fuse wires, spaced terminal means therefor, an insulating structure supporting said wires with the wires extendinggenerally longitudinally of the supporting structure, which said structure includes a plurality of disk-like elements extending transversely of the supporting structure in substantially parallel relationship and located respectively at intervals spaced apart substantial distances longitudinally of said structure, said disk-like elements having wire engaging means disposed therearound at points spaced from the centers of said elements and engaging said wires at points spaced apart along the lengths of the wires in a manner to maintain the wires in a substantially symmetrical arrangement around of said structure, and a filler of granular arc-quenchingmaterial surrounding and embedding the wires throughout the major portion of the lengths of the wires.

6. In a fuse device including a body of granular arc-quenching material and a plurality of fusible conductors extending through and embedded in said material, an insulating structure for supporting said conductors with the conductors extending longitudinally of the supporting structure, which said structure includes a plurality relation longitudinally of said structure with the disks extending transversely of said structure in substantially parallel relationship, said tubular means providing a longitudinal conductor receiving bore and said disks having means there- -around at spacedpoints from the centers of the disks for engaging said first mentioned longitudinally extending conductors at spaced points along the lengths of the conductors.

7. In a fuse device including a body of granular, arc-quenching material and a plurality of fusible conductors extending through and embedded in said material, an insulating structure for supporting said conductors with the conductors extending longitudinally of the supporting structure, which said structure includes a plurality of individual supporting units joined in end to end relationship, said units including disk-like elements arranged to extend transversely of the iongitudinal axis of the supporting structure and spacing elements projecting outwardly substantially from the centers of the disk-like elements and substantially normal to the disk-like elements for joiningto the next adjacent ones of the units, and said disk-like elements having conductor receiving means spaced from the centers thereof and arranged to. engage said conductors at spaced points along the lengths of the conductors.

8. In a fuse device including a body of granular, arc-quenching material and a plurality of fusible conductors extending through and embedded in said material, an insulating structure for supporting said conductors with the conductors extending longitudinally of the supporting structure,

which said structure includes a plurality of disklike elements and 'a supporting member extending through substantial-1y centrally located openings in the disk-like elements'with tubular spacing members disposed concentricallyof said supporting member intermediate adjacent ones of the disk-like elements for maintaining the disk-like elements, in longitudinally spaced apart relation-- ship, said disk-like elements having conductor receiving means spaced outwardly from the centers thereof and arranged to engage said conductors at spaced points along the lengths of the conductors.

9. In a fuse device including a body of granular,

arc-quenchingmaterial and a plurality of fusible conductors extending through and embedded in said material, an insulating structure for supporting said conductors with" the conductors extending longitudinally of the supporting structure, which said structure includes a longitudinally extending unitary ladder-like frame comprised of a pair of longitudinally extending side, members and a plurality of cross members extending between said side members, which said cross members are disposed in laterally staggered relationship and arranged to be engaged by said longitudinally extending conductorslat spaced points along the lengths of the conductors for effecting relatively sharp changes in direction of the conductors at their points of engagement with said cross members.

10. In a fuse device including a body of, granular arc-quenching material and a plurality of fusible conductors extending through and embedded 'in said material, an insulating structure for supporting said conductors with the conductors extending longitudinally of the supporting structure, which said structure includesla plurality of unitary frames, each comprising a pair of side members having a plurality of cross members extending therebetween in substantially. parallel spaced'relationship, which said frames are asseinbled so that the cross members are disposed in laterally spacedv relationship both longitudinally and transversely of said supporting structure with l lengths of the wires in the cross members extending in substantially parallel relationship transversely of the'supporting structure, each of said longitudinally extending conductors being successively engaged at spaced points'by longitudinally successive ones of said cross members and relatively sharply changing direction at each successive point of engagement in such manner that the conductors have a zigzag arrangement longitudinally of said supporting structure.

11. In a fuse device including a body of granular arc-quenching material, a plurality of fusible conductors extending in spaced relationship through and embedded in said material, and terminals for said conductors, an insulating supporting structure for the conductors including a plurality of unitary frames, each comprising a pair of side members having a plurality of cross members extending therebetween in'spaced apart substantially parallel relationship, which said frames are assembled in substantially parallel juxtaposition so that the cross members of each irame extend in spaced apart substantially parallel relation to the cross members of the respectivelyadjacent frames, each of said conductors at spaced points along its length engaging certain of said cross members and relatively sharply changing direction at successive points ofengagement so as to afford a zig-zag arrangement of the conductors in said supporting structure.

12. In a fuse device including-a body of granular arc-quenching material and a plurality of electrically parallel connected fusible conductors extending in spaced relationship through and embedded in said material, an insulating supporting structure for said conductors including a plurality of rows of substantially parallel laterally spaced apart cross members,- which said rows are arranged in substantially parallel juxtaposition with the cross members of each row in spaced apart substantially parallel relation to the cross members of the respectively adjacent rows,-each of said conductors being arranged to engage at opposite ends thereof, a large number of fusewires connected electricallyv said terminals and each having greater length than the shortest distance between'the terminals, an insulating structure supporting said wires with in parallel between the wires extending generally longitudinally of.

said casing and disposed in a substantially symmetrical. arrangement around the central longitudinal axis of the casing, said structure comprising a plurality of distinct wire engaging units extending transversely of the casing respectively at intervalsspaced longitudinally of the casing; which said units'engage said wires only. at points spaced apart substantial distances along the a mannerto maintain the wires in zigzagging courses. and a filler of granular arc-quenching material disposed in the spaces between said units and surrounding and embedding said wires throughout the major portion of the lengths of the" wires.

KARLXAUG. LOHAUSEN.

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