US3253106A - Indicating fuse constructions - Google Patents

Indicating fuse constructions Download PDF

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Publication number
US3253106A
US3253106A US191951A US19195162A US3253106A US 3253106 A US3253106 A US 3253106A US 191951 A US191951 A US 191951A US 19195162 A US19195162 A US 19195162A US 3253106 A US3253106 A US 3253106A
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United States
Prior art keywords
fuse
terminal
indicating
secured
capacitor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US191951A
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English (en)
Inventor
Howard R Holsinger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Westinghouse Electric Corp
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Westinghouse Electric Corp
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Filing date
Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US191951A priority Critical patent/US3253106A/en
Priority to JP3213163U priority patent/JPS4032281Y1/ja
Application granted granted Critical
Publication of US3253106A publication Critical patent/US3253106A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/36—Means for applying mechanical tension to fusible member

Definitions

  • This invention relates generally to indicating fuse constructions and, more particularly, to indicating fuse constructions wherein an indicating assembly is desired for externally indicating operation of the fuse in response to overload or fault conditions.
  • a general object of the present invention is to provide an improved indicating fuse construction of highlyefiicient operation, composed of few parts and yet providing an improved external indication of operation of the fuse under overload or fault conditions.
  • a more specific object of the present invention is the provision of an indicating-type fuse having relatively few parts, and associating an indicating-rod assembly with one of the terminals of the fuse, so as to give an external readily-visible indication of fuse operation.
  • a further object of the present invention is the provision of a fuse, particularly adapted for capacitor-unit installations, wherein an insulating fuse-indicator rod is employed, the fuse construction being very suitable for confinement within an enclosed cubicle construction without the hazard of any flashover occurring between the grounded cabinet and the indicator assembly to the live terminals of the fuse during fuse operation.
  • Still a further objectof the present invention is the provision of an improved method for assembling 'a fuseindicator device with a fuse for eliminating as far as possible soldered connections, and providing instead crimping operations, or threaded connections,.for good contact transfer and adequate securement of the several parts.
  • Still a further object of the present invention is the provision of an improved indicator assembly for a fuse having a fuse-indicating rod which protrudes axially through a fuse terminal to an external length sufficient for readilyvisible external indication.
  • Yet a further object of the present invention is the provision of an improved fuse construction wherein a biasing spring adapted for fuse-terminal withdrawal is also effective as a biasing means for an indicating-rod assembly.
  • FIGURE 1 is an end section view, partially in section, of an enclosed protected capacitor installation indicating internal stacking of capacitor units with individual protective fuse elements closely situated to the cabinet wall;
  • FIG. 2 is an enlarged axial sectional view taken through the improved indicating fuse construction of the present invention, with the fuse elements shown in their intact condition;
  • FIG. 3 is a fragmentary sectional view, similar to that of FIG. 2, but indicating the position of the several parts following blowing, or operation of the fuse elements;
  • FIGS. 4 and 5 illustrate, respectively, end and side elevational views of the deformed connector element of the present invention
  • FIGS. 6 and 7 illustrate, respectively, side elevational and end elevational views of the push-on-type speed nut utilized in an assembly operation of the present invention
  • FIGS. 8 and 9 illustrate, respectively, side elevational and end elevational views of the perforated condenser 'ice chamber utilized in the fuse construction of the present invention
  • FIGS. 10-12 illustrate, respectively, detailed views of the improved terminal-stud construction of the present invention.
  • FIGS. 13 and 14 illustrate, respectively, side elevational and end elevational views of the metallic crimp washer used in an assembly operation
  • FIGS. 15 and 16 illustrate, respectively, side elevational and end elevational views of the metallic connector sleeve utilized in the indicator assembly of the present invention.
  • FIG. 17 is afragmentary side elevational view indicating installation of the fuse construction of the present invention on the terminal of a capacitor unit.
  • the fuse construction of the pres ent invention may be utilized in a wide variety of applications, merely for the purpose of describing the present invention, and not by way of limitation, the fuse construction is illustrated as applied to an individual capacitor unit.
  • the primary purpose of fusing individual capacitor units is to remove a faulted capacitor from service before the capacitor case ruptures and damages adjacent units. The removal of the faulted capacitor unit must take place before the main protective device can operate and interrupt service to the remaining capacitor units, which are unaffected. Another purpose is to protect the unaffected capacitor units from the high transient current associated with the failure of a capacitor unit in the same capacitor bank.
  • Capacitor equipment usually consists of a number of individual capacitor units connected in parallel to make up the total capacity required for a given installation. In most installations, the complete equipment is protected by a circuit breaker or power fuses. The current rating is determined by the normal current rating of the equipment plus an ample margin to allow for increased current due to operation above rated voltage, manufacturing tolerances, presence of harmonics, and transient currents during switching operations.
  • individual capacitor units are liberally designed to withstand the requirements of normal service; nevertheless, a capacitor unit may fail if operated under abnormal conditions. Should this occur, no protection can be expected from the circuit breaker or power fuses, because of the high ratio of total bank current to the small current that can be drawn by a faulty capacitor unit. As a result, individual capacitor unit fuses are recommended for use on all power capacitor installations to provide maximum protection, preserve continuity of service and provide identification of a faulted capacitor unit.
  • a capacitor bank compartment 1 encloses a plurality of stacked capacitor units 2 in a plurality of banks 3.
  • Individual capacitor fuses 4 are secured to one of the terminals 6 of the capacitor units 2 for protection against fault conditions.
  • the indicating assembly 7 of the capacitor fuse 4 is situated relatively closely to the wall 8 of the compartment 1. As a result, there is the danger of flashover conditions occurring between the capacitor fuse 4 and the grounded compartment wall 8 if the fuse is not properly constructed.
  • the improved indicating fuse construction of the present invention comprises generally the addition of a condenser chamber, together with an indicator-rod assembly extending through the condensing chamber and also through the terminal stud. Electrical connection is preferably made to the terminal stud, which may also be used to support the fuse itself. As a result, the fuse may be mounted directly onto a capacitor bushing by means of a simple fiat mounting strap. Moreover, the fuse may also be mounted upon a capacitor bus for other installations.
  • the utilization of a condensing chamber permits the fuse to be used more closely adjacent other live parts, because the expelled gases, generated during fuse operation, are cooled and deionized by the condenser chamber.
  • FIG. 2 shows more clearly the improved fuse construction of the present invention.
  • the fuse 4 is of the current-limiting type for limiting the fault current passing through the fuse 4. More specifically, the fuse unit 4 isencased by a tubular fuse holder 9 made of insulating material, such as fiber, or synthetic resin and by a terminal cap 11 and condenser chamber 12 associated with opposite ends of the fuse tube 9.
  • the current-limiting section 13 includes a supporting or interrupting rod 14 of suitable insulating material, such as fiber, or the like.
  • the insulating rod 14 is helically grooved, as at 16, for the accommodation of a plurality of parallel-disposed current-limiting fuse wires 17, preferably of silver Wire.
  • fiber washers 18 are slipped over the helicallygrooved insulating rod 14 to prevent flashover, and to increase the arc voltage during a current-limiting operation.
  • a suitable filler such as quartz sand 19, is disposed interiorly of the fuse tube 9 for condensation of the fused metallic particles caused during fuse operation.
  • a boric-acid interrupting section 21 comprising a plurality of apertured boric-acid blocks 22, through which extends a fusible element 23 comprising a fuse wire 24 and a strain wire 26.
  • the fuse wire 24 and the strain wire 26 are suitably secured by means of a hole 27 bored transversely through a rod end portion 28, to which the plurality of silver fuse Wires 17 are conductively secured, as by solder.
  • the lower ends of the strain link 26 and main fuse element 29 are soldered to a crimped portion 30 of a fuse connector 31, the particular configuration of which is more clearly shown in FIGS. 4 and of the drawings.
  • an indicator compression spring 33 which is of coiled spring construction, is placed over the fuse connector 31, and is compressed by a crimp washer 34, the latter being shown more clearly in FIGS. 13 and 14 of the drawings.
  • a speed nut 36 is frictionally pressed on over the tubular portion 31a of the fuse connector 31 to temporarily frictionally maintain the indicator spring 33 in compression.
  • a connector sleeve 38 is slipped over the connector 31; and flexible leads 41 and insulating indicator rod 42 are inserted a short distance, such as or /2 inch for example, into the open tubular end 31b of connector 31.
  • the rod 42 is centered in the several strands of flexible leads 41.
  • a first crimping step takes place by means of pressing the connector sleeve 38, shown in FIGS. 15 and 16, over the tubular portion 31a of the fuse connector 31 to deform the same to an oval configuration.
  • Such a oval deformation maintains the crimp washer and the push-on-type speed nut 36 into a fixed permanent position as contrasted to the previous temporary position of the speed nut 36), so that the lower end of the indicating spring 33 is fixedly determined into a proper permanent position, as shown in FIG. 2.
  • the upper end of sleeve 38 and end 31a of connector 31 are crimped simultaneously the operation also securing the leads 41 fixedly into position.
  • a second crimping operation is subsequently performed between the lower end of the connector sleeve 38 and the flexible leads 41 and the insulating indicator rod 42.
  • the second crimping operation thereby ensures a fixed securement of the insulating indicator rod 42 together with the flexible leads 41 into a proper position and importantly provides additional contact between leads 41 and connector sleeve 38, and hence to connector 31.
  • the lower ends of the flexible leads 41 have terminal lugs 43 secured thereto, which terminal lugs are fastened by mounting screws 44 to a terminal stud 46, the particular configuration of which is more clearly shown in FIGS. l012 of the drawings.
  • a transversely-extending hole 47 is provided, and tapped, to accommodate the mounting screws 44.
  • an axial bore 48, through the terminal 46 is provided for the accommodation of the insulating indicator rod 42.
  • the terminal stud 46 has a shoulder portion 49 adapted for insertion through a substantially square hole 51 of the tubular condenser chamber 52, the configuration of which is more clearly shown in FIGS. 8 and 9 of the drawings.
  • the terminal stud 46 will not turn within the hole 51 of condenser cap 52 upon rotation of a clamping, or jam nut 53.
  • a lock washer 54 and an oversized metallic washer 56 are additionally employed under the nut 53.
  • the fuse 4 may be fixedly secured to the terminal 58 of a capacitor unit 2.
  • the fuse 4 will function to provide a current-limiting action, 'as provided by the currentlirniting section 13. Additionally, the fusible element 23 will blow to release the indicator spring 33, which additionally functions as a fuse-terminal retraction spring.
  • the indicator rod 42 will be ejected to a readily-visible external position, as indicated in FIG. 3 of the drawings.
  • the assembly operations are performed by first lowering the current-limiting fuse section 13, together with the fusible element 23 and attached connector sleeve 30, through the bore 59 of the fuse tube 9, so that the terminal cap 11 may be crimped into an annular recess 60 provided thereon.
  • a square centering washer 61 is employed to center the currentlimiting interrupter rod 14.
  • the fuse tube 9 is preferably inverted so that the cap 11 is positioned downwardly, at which time a suitable filler, such as quartz sand 19, is poured downwardly into the fuse tube 9 past the square positioning washer 6-1.
  • the tube 9 may be vibrated to settle and compact the sand.
  • a closure washer 62 of round configuration is pushed over a tapered portion 63 of the fuse rod 14.
  • the boric-acid blocks 22 are placed, or stacked into position together with a metallic apertured spring-seat washer 6 5, which provides a metallic seat for one end of the indicator spring 33.
  • the spring 33, crimp washer 34, and frictionally-engaging speed-nut 36 are pushed over connector 31.
  • the speednut 36 temporarily holds the lower end of the spring 33 in positiomas viewed in FIG. 2.
  • connector sleeve 38 is slipped loosely over connector 31.
  • the flexible leads 41, together with indicator rod 42, are inserted into the open tubular end 31b of the fuse connector 31; and the aforesaid first crimping operation is performed. Subsequently, the second crimping operation is additionally performed to provide thereby additional secure attachment of the leads 41 with the connector sleeve 38 with good current-carrying qualities. This assures additional contact between leads 41 and sleeve 38 and hence to connector 31.
  • the terminal lugs 43, secured to the flexible leads 41, are secured by the mounting screws 44 into the transversely-tapped bores 47 of the terminal 46.
  • a rolled-up copper screen 68 is inserted into the condensing chamber 52 for the condensation of the evolved gases during fuse operation and the condenser closure '52 is slipped over the reduced end 46a of the terminal stud 46, and the crimping operation performed to crimp sleeve portions 70 into annular recesses 71 for secure attachment.
  • the condenser chamber 52 has venting apertures 67 associated therewith for expulsion of the generated gases.
  • the jam nut 53 is tightened over the lock washer 5'4 and oversize washer 56 to fixedly force the enlarged portion 46b of the terminal stud 46 against the inside surface 73 of the end 74 of condenser chamber 5-2.
  • the novel indicating fuse construction of the present invention has an additional advantage inasmuch as the expelled gases, generated during fuse operation, are cooled and deionized prior to ejection through the venting holes 67 of condenser chamber 52 to the atmosphere.
  • an indicating fuse including a fuse- -cap terminal secured to one end of a tubular insulating fuse holder, a tubular apertured metallic condensing chamber secured to the other end of the fuse holder, means defining a current-limiting section, a tubular gas-evolving axial-bore-type interrupting section having rupturable fuse means therein, a condensing chamber section, a deformed tubular fuse connector, said rupturable fuse means being secured to the deformed end of the fuse connector, an indicating insulating rod, at least one fuse cable secured to the undeformed end of the tubular connector, a terminal stud having an axial bore therethrough secured to said condensing chamber and having said indicating rod extending through the axial bore thereof, and means conductively securing the other end of said fuse cable to the interior end of the terminal stud.
  • an indicating fuse including a fusecap terminal secured to one end of a tubular insulating fuse holder, a tubular apertured metallic condensing chamber secured to the other end of the fuse holder, means defining a current-limiting section, a tubular gas-evolving axial-bore-type interrupting section having fusible fuse means therein, a condensing chamber section, a deformed tubular fuse connector, said fusible fuse means secured to the deformed end of the fuse connector, an indicating insulating rod and at least one fuse cable secured to the undeformed end of the tubular connector, a terminal stud having an axial bore therethrough secured to said condensing chamber and having said indicating rod extendin axially through the axial bore thereof, and an indicator spring encircling said deformed tubular fuse connector and biasing the same to an indicating condition of the fuse wherein said indicator rod is ejected along said terminal stud bore.

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US191951A 1962-05-02 1962-05-02 Indicating fuse constructions Expired - Lifetime US3253106A (en)

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Application Number Priority Date Filing Date Title
US191951A US3253106A (en) 1962-05-02 1962-05-02 Indicating fuse constructions
JP3213163U JPS4032281Y1 (en:Method) 1962-05-02 1963-05-02

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US191951A US3253106A (en) 1962-05-02 1962-05-02 Indicating fuse constructions

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JP (1) JPS4032281Y1 (en:Method)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3733572A (en) * 1970-12-24 1973-05-15 Mc Graw Edison Co Current limiting fuse
US4114128A (en) * 1974-10-30 1978-09-12 Westinghouse Electric Corp. Composite sectionalized protective indicating-type fuse
US5659283A (en) * 1994-12-30 1997-08-19 Arratia; Jose F. Indicating fuse block
USRE36317E (en) * 1994-12-30 1999-09-28 Arratia; Jose F. Indicating fuse block

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1655842A (en) * 1925-09-10 1928-01-10 Emmet F Pelletier Fuse
US2071435A (en) * 1934-05-07 1937-02-23 Delle Atel Const Electr Combined flame baffle and indicator for fusible cut-outs
US2165636A (en) * 1935-12-03 1939-07-11 Southern States Equipment Corp Electric fuse
US2294767A (en) * 1940-08-02 1942-09-01 Gen Electric Electric protective device
US2412712A (en) * 1942-07-27 1946-12-17 Line Material Co Method of assembling fuse links
US2421658A (en) * 1943-04-28 1947-06-03 Gen Electric Circuit interrupting device
US2435472A (en) * 1944-11-17 1948-02-03 Gen Electric Circuit interrupting device
US2483577A (en) * 1943-11-24 1949-10-04 Westinghouse Electric Corp Circuit interrupter
US2493434A (en) * 1946-03-21 1950-01-03 Joslyn Mfg And Supply Company Method of manufacturing fuse links
US2567768A (en) * 1946-03-15 1951-09-11 Westinghouse Electric Corp Circuit interrupter
US2813952A (en) * 1954-11-01 1957-11-19 S & C Electric Co Bayonet type circuit interrupter
US2872549A (en) * 1956-08-07 1959-02-03 S & C Electric Co Fuse link construction
US2918551A (en) * 1958-11-21 1959-12-22 Chase Shawmut Co Fuses with built-in indicating plungers

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1655842A (en) * 1925-09-10 1928-01-10 Emmet F Pelletier Fuse
US2071435A (en) * 1934-05-07 1937-02-23 Delle Atel Const Electr Combined flame baffle and indicator for fusible cut-outs
US2165636A (en) * 1935-12-03 1939-07-11 Southern States Equipment Corp Electric fuse
US2294767A (en) * 1940-08-02 1942-09-01 Gen Electric Electric protective device
US2412712A (en) * 1942-07-27 1946-12-17 Line Material Co Method of assembling fuse links
US2421658A (en) * 1943-04-28 1947-06-03 Gen Electric Circuit interrupting device
US2483577A (en) * 1943-11-24 1949-10-04 Westinghouse Electric Corp Circuit interrupter
US2435472A (en) * 1944-11-17 1948-02-03 Gen Electric Circuit interrupting device
US2567768A (en) * 1946-03-15 1951-09-11 Westinghouse Electric Corp Circuit interrupter
US2493434A (en) * 1946-03-21 1950-01-03 Joslyn Mfg And Supply Company Method of manufacturing fuse links
US2813952A (en) * 1954-11-01 1957-11-19 S & C Electric Co Bayonet type circuit interrupter
US2872549A (en) * 1956-08-07 1959-02-03 S & C Electric Co Fuse link construction
US2918551A (en) * 1958-11-21 1959-12-22 Chase Shawmut Co Fuses with built-in indicating plungers

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3733572A (en) * 1970-12-24 1973-05-15 Mc Graw Edison Co Current limiting fuse
US4114128A (en) * 1974-10-30 1978-09-12 Westinghouse Electric Corp. Composite sectionalized protective indicating-type fuse
US5659283A (en) * 1994-12-30 1997-08-19 Arratia; Jose F. Indicating fuse block
USRE36317E (en) * 1994-12-30 1999-09-28 Arratia; Jose F. Indicating fuse block

Also Published As

Publication number Publication date
JPS4032281Y1 (en:Method) 1965-11-11

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