High voltage fuse adapter system and method

Abstract

A high voltage fuse adapter system and method. A fuse adapter system includes an indicator-end adapter configured to circumferentially enclose an indicator-end terminal of a high voltage IEC rated fuse, including a hollow portion having an inner diameter that surrounds the indicator-end terminal, the hollow portion including at least one axially extending slot compressible around the indicator-end terminal, and an indicator portion, a piston and needle enclosed within the indicator portion, the piston and needle coupled to a striker of the high voltage IEC-rated fuse such that upon extension of the striker, the piston at least partially actuates the needle outside of the indicator-end adapter, a non-indicator-end adapter configured to circumferentially enclose a non-indicator-end terminal of the high voltage fuse, and a pair of end caps enclosing the indicator-end adapter and the non-indicator end adapter to form an adapted fuse configured to fit in an UL-style fuse mounting.

Claims

1. A high voltage fuse adapter system comprising: an indicator-end adapter configured to circumferentially enclose an indicator-end terminal of a high voltage International Electrotechnical Commission (IEC)-rated fuse, comprising: a hollow portion having an inner diameter that surrounds the indicator-end terminal, the hollow portion comprising at least one axially extending slot compressible around the indicator-end terminal; and an indicator portion; a piston and needle enclosed within the indicator portion, the piston and needle coupled to a striker of the high voltage IEC-rated fuse such that upon extension of the striker, the piston at least partially actuates the needle outside of the indicator-end adapter; a non-indicator-end adapter configured to circumferentially enclose a non-indicator-end terminal of the high voltage fuse; and a pair of end caps enclosing the indicator-end adapter and the non-indicator end adapter to form an adapted fuse; wherein the adapted fuse is configured to fit in an Underwriters Laboratory (UL)-style fuse mounting.

2. The high voltage adapter system of claim 1, wherein the hollow portion of the indicator-end adapter covers the indicator-end terminal.

3. The high voltage adapter system of claim 1, wherein a first end cap of the pair of end caps encloses the indicator-end adapter, the first end cap having an opening, and wherein the needle extends through the opening when actuated by the piston.

4. The high voltage adapter system of claim 1, wherein the hollow portion mates with the indicator-end terminal, and the indicator portion extends on an outward side of the indicator-end adapter.

5. The high voltage adapter system of claim 1, wherein the at least one axially extending slot comprises two axially extending slots arranged 180 degrees apart.

6. The high voltage adapter system of claim 1, wherein the indicator-end adapter and the non-indicator-end adapter are silver plated.

7. The high voltage adapter system of claim 1, wherein the piston is threadedly connected to the needle, and the piston extends circumferentially around an outer diameter of the striker.

8. The high voltage adapter system of claim 1, wherein the at least one axially extending slot is compressible by at least one radially-oriented screw extending through an aperture in the indicator-end adapter.

9. The high voltage fuse adapter system of claim 1, wherein the high voltage IEC-rated fuse is an IEC standardized Ferrule-style fuse of 15.5 kV Volts and one of 125, 150, 175 or 200 Amperes.

10. The high voltage fuse adapter system of claim 9, wherein the UL-style fuse mounting is a CLE/CLS UL style fuse clip mounting.

11. The high voltage fuse adapter system of claim 1, wherein the non-indicator end adapter further comprises a second at least one axially extending slot compressible around the non-indicator-end terminal.

12. A method of employing a single International Electrotechnical Commission (IEC) fuse in an Underwriters Laboratory (UL)-style fuse mounting, comprising: enclosing an indicator-end of the single IEC fuse inside a first adapter piece that lengthens and widens the indicator-end; coupling a piston and needle to a striker of the single IEC fuse such that the needle is visible outside the adapter when the single IEC fuse breaks; enclosing the non-indicator-end of the single IEC fuse inside a second adapter piece; capping the first and second adapter pieces with end caps; and mounting the single IEC fuse with adapters and end caps into the UL-style mounting.

13. The method of claim 12, further comprising compressing the first adapter piece around the indicator end to mate a hollow portion of the adapter piece to the indicator end.

14. The method of claim 12, wherein the striker of the single IEC fuse actuates the needle at least partially out of the adapter when the single IEC fuse breaks.

15. The method of claim 12, further comprising silver-plating the first and second adapter piece.

16. The method of claim 12, further comprising taking a resistance reading subsequent to enclosing the indicator-end and the non-indicator end of the single IEC fuse inside the first adapter piece and the second adapter piece.

17. The method of claim 12, further comprising employing the mounted single IEC fuse in a phase of a North American style disconnect switch.

18. A system for utilizing an International Electrotechnical Commission (IEC)-rated fuse in North American style equipment comprising a pair of adapter pieces that compressibly mate around respective terminals of the IEC-rated fuse such that the IEC-rated fuse is configured to fit within a pair of Underwriters Laboratory (UL) standard fuse caps and an indicator is visible outside at least one adapter piece of the pair of adapter pieces and its corresponding UL standard fuse cap upon overload of the IEC rated fuse.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Advantages of the present invention may become apparent to those skilled in the art with the benefit of the following detailed description and upon reference to the accompanying drawings in which:

(2) FIG. 1 is a perspective view of a North American style double fuse arrangement of the prior art.

(3) FIG. 2 is a perspective view of a standardized IEC fuse of the prior art.

(4) FIG. 3A is a perspective as viewed from the inward side of an indicator-end adapter piece of an illustrative embodiment.

(5) FIG. 3B is a perspective as viewed from the outward side of an indicator-end adapter piece of an illustrative embodiment.

(6) FIG. 3C is a cross sectional view across line 3C-3C of FIG. 3A of an indicator-end adapter piece of an illustrative embodiment.

(7) FIG. 4A is a perspective as viewed from the inward side of a non-indicator-end adapter piece of an illustrative embodiment.

(8) FIG. 4B is a perspective as viewed from the outward side of a non-indicator-end adapter piece of an illustrative embodiment.

(9) FIG. 4C is a cross-sectional view across line 4C-4C of FIG. 4A of a non-indicator-end adapter piece of an illustrative embodiment.

(10) FIG. 5 is a perspective view of an IEC fuse with attached adapter of illustrative embodiments.

(11) FIG. 6 is an exploded view of an IEC fuse with attached adapter of illustrative embodiments.

(12) FIG. 7A is a partial cross-sectional view across line 7A-7A of FIG. 5 of an exemplary indicator-end adapter with a piston and needle of illustrative embodiments in an un-activated position.

(13) FIG. 7B is a partial cross-sectional view of an exemplary indicator-end adapter with a piston and needle of illustrative embodiments in an overload position.

(14) FIG. 8 is a perspective view of an exemplary IEC fuse with adapter of illustrative embodiments fit into a UL style mounting.

(15) While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and may herein be described in detail. The drawings may not be to scale. It should be understood, however, that the embodiments described herein and shown in the drawings are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION

(16) A high voltage fuse adapter system and method will now be described. In the following exemplary description, numerous specific details are set forth in order to provide a more thorough understanding of embodiments of the invention. It will be apparent, however, to an artisan of ordinary skill that the present invention may be practiced without incorporating all aspects of the specific details described herein. In other instances, specific features, quantities, or measurements well known to those of ordinary skill in the art have not been described in detail so as not to obscure the invention. Readers should note that although examples of the invention are set forth herein, the claims, and the full scope of any equivalents, are what define the metes and bounds of the invention.

(17) As used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a slot includes one or more slots.

(18) As used in this specification and the appended claims, “high voltage” means 600 Volts or above.

(19) As used in this specification and the appended claims, “coupled” refers to either a direct connection or an indirect connection (e.g., at least one intervening connection) between one or more objects or components. The phrase “directly attached” means a direct connection between objects or components.

(20) In the art, a 15,000 Volt fuse is sometimes referred to as a 15.5 kV fuse. Both such terms are used interchangeably to refer to a fuse able to withstand up to 15.5 kV.

(21) One or more embodiments of the invention provide a high voltage fuse adapter. While for ease of description and so as not to obscure the invention, illustrative embodiments are described in terms of a 15,000 Volt fuse, nothing herein is intended to limit the invention to that embodiment. The invention may be applied equally to fuses with other voltages and currents.

(22) Since the discontinuation of single E-rated fuses, resellers and end-users of high voltage fuses have recognized a need to replace the double-barrel design required for 15,000 Volt E-rated fuses in North America with a less-expensive, lower footprint alternative that continues to operate reliably and does not interfere with the functioning of the overload indicator. Illustrative embodiments may solve this need by, and may include, a high voltage fuse adapter. The adapter of illustrative embodiments may modify a single IEC fuse to fit into a UL style single-barrel mounting in high voltage embodiments. A piston and needle of illustrative embodiments coupled to the striker of the IEC fuse may provide a visible indication of overload despite the striker being covered inside the adapter of illustrative embodiments. The adapter allows a single fuse per phase to be employed, rather than a set of two North American style fuses. Using a single fuse per phase amounts to considerable cost savings since it obviates the need to replace mounting blocks in legacy equipment. A single IEC fuse also has a smaller footprint than the double barrel design, thus saving space and material in newbuild applications. In addition, as of the date of this writing, a single high voltage fuse costs approximately $2,000 USD, and an IEC fuse costs about half of one E-rated fuse.

(23) Illustrative embodiments may include a pair of adapter pieces that attach to the indicator and non-indicator side of an IEC fuse. Each adapter piece may be cylindrical in shape with a hollow portion, slotted and screwed, snapped and/or fit tightly around the terminal ends of the fuse. The adapter pieces may increase the length and width of the terminal ends of the IEC fuse such that the IEC fuse can accommodate a three-inch diameter fuse cap, which is the UL standard that matches fuse clip dimensions of the single barrel UL design used in North American applications. The fuse caps, which may also be called end caps, may be placed over each adapter prior to mounting. Thus, making illustrative embodiments “plug and play”. The indicator-side adapter piece may include an internal piston and needle that aligns with the striker of the IEC fuse. Should the fuse become overloaded and the striker be triggered, the striker may hit, push and/or move the piston, and the needle may extend out of the adapter body as a visible indicator of overload. The adapter pieces of illustrative embodiments may be silver plated after machining and prior to assembly to ensure good electrical conductivity. A resistance reading of the fuse may be conducted prior to assembly and after assembly to ensure the characteristic of the final product has not been changed and provide the user with confidence that the adapter is functioning properly.

(24) FIGS. 3A-3C illustrate an indicator-end adapter piece of illustrative embodiments. Indicator-end adapter 300 may be substantially cylindrical and/or tubular in shape with one closed end 345, and one open end circumferentially defined by inner edge 310. Indicator-end adapter 300 may include a pair of axial slots 305 extending from inner edge 310 axially towards the center of indicator-end adapter 300, and radially through the thickness of the wall of hollow portion 320 of the adapter 300 body. In some embodiments, two axial slots 305 may be set 180° apart, although one, three, four or another similar number of slots 305 may be employed. A set and/or plurality of apertures 315 may extend radially into the body of indicator-end adapter 300 adjacent to slot 305. Screws 600 (shown in FIG. 6) inserted into apertures 315 may tighten indicator-end adapter 300 around indicator-end terminal 605 (shown in FIG. 6) of fuse 500 (shown in FIG. 5). Compression of slots 305 when screws 600 are inserted may provide indicator-end adapter 300 tension to clamp around indicator-end terminal 605. In some embodiments, each screw 600 may extend through a pair of apertures arranged on opposing sides of slot 305. In some embodiments, indicator-end adapter 300 may snap-on and/or be secured by an adhesive.

(25) Indicator-end adapter 300 may include hollow portion 320. Hollow portion 320 may provide a female connection to mate snugly with indicator-end terminal 605 and/or cover indicator-end terminal 605. Indicator portion 325 of indicator-end adapter 300 may include an inner diameter that forms piston cavity 335 and needle-shaped channel 340. Axially extending passages 330 may accommodate fasteners 615 (shown in FIG. 6) for attachment of fuse cap 610 (shown in FIG. 6) to indicator-end adapter 300. Fasteners 615 may for example be screws or bolts. Fuse cap 610 may be a three-inch diameter fuse cap 610, for example in UL standard embodiments. Piston cavity 335 may be contiguous with hollow portion 320 and may mate with the outer diameter of piston 700 (shown in FIG. 7), while providing axial space for piston to move between an un-activated position and an overload position.

(26) FIGS. 4A-4C illustrate a non-indicator-end adapter piece of illustrative embodiments. Non-indicator-end adapter 400 may secure around non-indicator terminal 620 (shown in FIG. 6) of fuse 500 (shown in FIG. 5). Non-indicator-end adapter 400 may be similar to indicator-end adapter 300, except rather than indicator portion 325, non-indicator-end adapter 400 may include solid portion 405 and end face 410. Solid portion 405 may provide a base for non-indicator-end adapter 400 to secure to fuse cap 610.

(27) Indicator-end adapter 300 and non-indicator-end adapter 400 may be 360 brass and silver plated to ensure good electrical conductivity. Silver plating may be 0.0001 inches thick and may be applied after machining and prior to attachment of adapters 300, 400 onto fuse 500. In one non-limiting example, to form a 15.5 kV E-rated fuse size D from standardized IEC fuse 500, adapters 300, 400 may each be about 3.19 inches in length and about 2.872 inches in outer diameter. Passages 330 may be about 0.750 inches deep.

(28) FIG. 5 illustrates a fully assembled fuse 500 modified with adapters 300, 400 attached and end caps 610 secured over adapters 300, 400. As shown in FIG. 5, fuse 500 may match fuse clip dimensions of single-barrel UL mounting 800 (shown in FIG. 8). Fuse 500 may be an IEC standardized Ferrule-style fuse of 15,000 Volts and 125, 150, 175 or 200 Amperes. Fuse 500 may be available from Eaton Corporation plc of Dublin, Ireland, Littlefuse, Inc. of Chicago, Ill., USA, or Mersen SA of La Défense, France.

(29) FIG. 6 is an exploded view of fuse 500 illustrated in FIG. 5. Prior to attachment of adapters 300, 400, fuse 500 may be shaped similarly to a rolling pin. Striker 625 may be included on indicator-end terminal 605. When fuse 500 overloads, striker 625 may pop out of indicator-end terminal 605 and is designed to be visible so that an operator may observe overload has occurred. However, adapter 300, when employed, may cover striker 625 so striker 625 is no longer visible even when extended. To alleviate this problem, piston 700 and needle 705 may be axially aligned with striker 625 and/or piston may nest over striker 625. Fuse cap 610 may be screwed over adapter 300. Fuse cap 610 on indicator-end of fuse 500 may include central opening 635 to allow needle to extend through and be visible outside of fuse cap 610 when fuse 500 becomes overloaded. Fuse cap 610 may include holes 630 that align with passages 330 to allow fasteners 615 to extend through both holes 630 and passages 330 and secure fuse cap 610 to adapter 300, 400.

(30) FIG. 7A and FIG. 7B illustrate the action of striker 625, piston 700 and needle 705 in the event of overload of fuse 500. Piston 700 may be placed over and around the end portion of striker 625, such that striker 625 may nest inside of piston 700. In some embodiments, piston 700 may rest against the face of striker 625 with piston 700 adjacent to striker 625. In certain embodiments, movement and/or extension of striker 625 may initiate movement of piston 700 and/or needle 705 and/or striker 625 may cause a chain reaction that actuates and/or moves piston 700 and/or needle 705. For example, striker 625 may exert force upon piston 700, which piston 700 in turn may move needle 705 such that needle 705 is visible outside fuse cap 610 upon overload of fuse 500. In some embodiments, piston 700 may be secured, attached and/or coupled on and/or tightly around striker 625, such as by friction fit.

(31) In illustrative embodiments, piston 700 may be aluminum and needle 705 may be 300 series stainless steel in one non-limiting embodiment. In exemplary embodiments, needle 705 may be about 1.670 inches in length, and needle 705 and piston 700 assembled length may be about 1.8 inches. The length of needle 705 and piston 700 should be such that needle 705 does not extend and/or is not visible outside fuse cap 610 if fuse 500 is not broken, and alternatively visible outside fuse cap 610 if fuse 500 overloads. In some embodiments, needle 705 may be attached to piston 700 with a threaded connection.

(32) Upon overload, striker 625 may extend outward from fuse 500 in the direction of arrow 710, as shown in FIG. 7B. Piston 700 may be pushed outward and/or actuated by striker 625, which in turn may extend needle 705 outward and through channel 340 such that needle extends through opening 635 in fuse cap 610. Needle 705 may therefore be visible upon overload of fuse 500 and function as a visible indicator of overload. Piston cavity 335 may provide space to allow piston 700 to actuate between an un-activated position and an overload position.

(33) FIG. 8 illustrates a fuse with adapter of illustrative embodiments mounted in a CLE/CLS UL style fuse clip mounting. Terminal ends 605, 620 of fuse 500 are enclosed within adapters 300, 400 and fuse caps 610. Mounting 800 fuse clip connections may match fuse clip dimensions of the single-barrel North American design whilst using an IEC standardized fuse 500. The final fuse assembly (for example, MVE15/XXXA-CLE) as shown in FIG. 8 may be constructed using bolts 615 and hand tools. A resistance reading of fuse 500 may be conducted prior to assembly and after assembly to ensure the characteristic of the final product have not changed.

(34) Illustrative embodiments may enable the utilization of IEC style fuses in North American equipment. Illustrative embodiments may convert the physical dimensions of an IEC fuse design without inhibiting the functioning of the fuse or interfering with the visible indication of overload of the fuse. Illustrative embodiments may conserve resources by replacing a single fuse where two fuses would otherwise be required. Those of skill the art may appreciate that the adapter system of illustrative embodiments may be employed with other voltages and currents other than 15,000 Volts.

(35) A high voltage fuse adapter system and method has been described. Further modifications and alternative embodiments of various aspects of the invention may be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the scope and range of equivalents as described in the following claims. In addition, it is to be understood that features described herein independently may, in certain embodiments, be combined.