MXPA98006682A - Fusi element - Google Patents

Fusi element

Info

Publication number
MXPA98006682A
MXPA98006682A MXPA/A/1998/006682A MX9806682A MXPA98006682A MX PA98006682 A MXPA98006682 A MX PA98006682A MX 9806682 A MX9806682 A MX 9806682A MX PA98006682 A MXPA98006682 A MX PA98006682A
Authority
MX
Mexico
Prior art keywords
fuse
conductors
separable
interengaged
fuse material
Prior art date
Application number
MXPA/A/1998/006682A
Other languages
Spanish (es)
Inventor
R Borchardt Glenn
Original Assignee
S&C Electric Company
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by S&C Electric Company filed Critical S&C Electric Company
Publication of MXPA98006682A publication Critical patent/MXPA98006682A/en

Links

Abstract

A fuse element is provided which includes cooperating interengaged parts surrounded by a fuse material. The cooperating interengaging portions are thus arranged to place the compressive force on the fuse material in response to an attempted separation of the interengaged parts. In addition, the arrangement also reduces forces on the fuse material. In response to a previously determined current-time condition, the fuse material softens sufficiently to allow the release and separation of the interajustad parts.

Description

FUSE ELEMENT BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to fuse elements for circuit interruption devices, such as switches, circuit breakers and the like, and more particularly to a fuse element that has operating and safety characteristics. in improved performance in order to provide a high overvoltage capacity to avoid undesirable detrimental operations. Description of Related Art Various types of circuit interruption devices in the field of electrical power distribution and transmission employ fuse elements that are designed to provide desirable characteristics for circuit interruption, i.e., time-current characteristic. Time-current characteristics include protection against leakage currents and other overload currents. For example, the ANSI C37.42 standard describes various time-current characteristics. Circuit interrupting devices are used in different locations in electrical systems to provide different functions along with the coordination of one with respect to the other to provide a safer system and minimize the standstill and a number of energy users affected in the system. In certain applications, it is desirable to provide both leakage protection and overload protection, while avoiding damaging stalls in response to defined high-voltage conditions, which are defined in terms of current and time, for example, i2t. For example, for various specific applications, it is desirable to avoid operation unless the current exceeds a specific percentage of rated current, for example 130% to 150% of the rated current. One type of device for this purpose is a double element fuse link including a first fuse element that responds to leakage currents according to the previously determined time-current characteristics and the second fuse element that provides the non-disruptive capability high overvoltage while responding to low overcurrents according to the i2t characteristics. For example, double-element fusible tapes of this type are described in the following US Patents: 2,361,666; 2,416,428; 2,493,601 and 4,994,779 and in Cooper Power Systems D-Link Fuse Bulletin 90016, June 1990. The fusible tape of US Patent 2,493,601 includes attachable members that are jointly held together by a metal fuse that is melted by the occurrence of a low sustained current heating to allow sliding separation of the members. In U.S. Patent No. 2,361,666 a fusible tape includes hook-coupled members surrounded by an insulating bead of a melting-point metal. When the insulator bead is softened, the current flows, the members that are under tension are separated by means of aligning the coupling portions engaged. These types of fusible tapes can be used with various circuit interruption devices, for example two illustrative types are shown in U.S. Patent Nos. 4,307,369, 4,317,099 and 5,502,427. While the prior art fuse elements may be generally suitable for their intended uses, they may still be subject to detrimental shutdowns as a result of an undesirable operation in response to prolonged underload or undervoltage currents. Accordingly, it is a main object of the present invention to provide a fusible element having high overvoltage non-disrupting capabilities that are not susceptible to prolonged low overload or overvoltage currents. It is another object of the present invention to provide a fusible element including cooperating interengaged parts surrounded by a fuse material with the parts that are arranged to establish the compressive force in the fuse material in response to the separation of the interengaged parts so that respond to a predetermined time-current condition, the fuse material softens enough to allow the release and separation of the interengaged parts. It is a further object of the present invention to provide a fuse element that includes the co-operating interengages surrounded by a fuse material with the parts that are arranged to reduce the forces in the fuse material in response to the separation of the interengaged parts, is say, so that the fuse material is under a lower mechanical load. These and other objects of the present invention are efficiently accomplished by a fuse element, which includes cooperating interengaged parts surrounded by the fuse material. The cooperating interengaging portions are arranged to place the compressive force on the fuse material in response to an attempted separation of the interengaged parts. In addition, the arrangement also reduces the forces on the fuse material. In response to a previously determined time-current condition, the fuse material softens sufficiently to allow the release and separation of the interengaged parts. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be understood, both its organization and method of organization together with the objects and advantages thereof, with reference to the specification taken in conjunction with the accompanying drawings, in which: Figures 1- 4 are views in front elevation, partially in section of a fuse element according to a first embodiment of the present invention and illustrating the various stages of operation; Figure 5 is an enlarged partial view of the fuse element of Figures 1-5; and Figures 7-10 are front elevational views partially in section of a fuse element according to a second embodiment of the present invention and illustrating various stages of operation. DETAILED DESCRIPTION Referring now to Figures 1-6, a fuse element 10 according to a first embodiment of the present invention includes first and second conductors 12, 14 and an electrothermally responsive array 16 that responds to predetermined current-time conditions. to cause the separation of the conductors 12, 14. The electrothermally responsive arrangement 16 includes a first terminal 18 conveyed in the first conductor 12 having an elongated cavity 20. An insurance lever 22 is pivotally mounted within the cavity 20 in a point 24 by a pin 26. The safety lever 22 includes a receiving groove 28. The second conductor 14 is provided with a hook section 30 which is assembled within the receiving groove 28 with the fuse material 21 disposed within the cavity 20 surrounding the lock lever 22 and the hook 30. In the position shown in Figure 1, under normal operating conditions, the conductors 12, 14, separation is prevented due to the stiffness of fuse material 21. In typical applications, fuse material 21 is of the type (e.g., weld or the like) which dramatically shows reduced strength and stiffness increase temperatures. When the conductors 12, 14 are placed under tension, the forces tending to separate the safety lever 22 and the hook 30 place the fuse material 21 in compression and the arrangement reduces the forces in the fuse material 21 relative to the tension on the conductors 12, 14, that is, in compression, the fuse material 21 has more resistance, and there is less mechanical load on the fuse material 21 relative to the conventional arrangements where the conductors 12, 14 are only engaged. When the fuse material is melted, the lock lever 22 pivots as shown in Figures 2-4, to release the hook 30 and allow for the separation of the conductors 12, 14. According to a preferred embodiment, the lever secure 22 includes an outer periphery tapered at 32 to provide space according to the pivot lock lever, for example, to minimize the space required in a wall 34 of a liner or the like, when the fuse element 10 is used in an assembly of conventional fusible tape. In an exemplary embodiment, conductors 12, 14 are a fabricated form of Nichrome wire. Referring now to Figure 5, and in consideration of the important aspects of the present invention, the safety lever 22 on an insurance arm portion 36 includes a ramp surface 38 adjacent the receiving groove 28. The ramp surface 38 is disposed with respect to the pivot point 24, in order to provide a constant sufficient force in the opening direction to overcome the frictional forces when the hook 30 moves along the ramp surface 38. The arm portion secure 36 in 40 includes a steeper curvature so that such force increases when the hook 30 moves past the ramp surface 38, thus ensuring proper release of the hook 30 when the safety lever 22 pivots. With the configuration and relative geometry as shown in Figure 5, an "a" angle (as defined by being shown in Figure 5), of approximately 6 degrees for the ramp surface 38, has been adequately fused to provide sufficient opening forces to overcome the frictional forces and pivot the lock lever 22, while minimizing the forces on the fuse material 21, thereby increasing the desired high overvoltage and overload non-disrupting characteristics. Now considering a second embodiment of the present invention and with reference now to Figures 7-10, a fuse element 50 includes first and second conductors 52, 54. A first terminal 56 is transported in the first conductor 52 having a cavity 60. A securing element 62 (eg, a pin) is transported by the first terminal 56 within cavity 60. Second conductor 54 includes a latch member 66 having a ramp surface 68 defining a reduced section 70. Fuse element 50 is assembled with latch member 66 positioned with respect to the element 63, so that the ramp surface 68 abuts and is clamped against the safety element 62. Additionally, in this position, the fuse material 72 is provided to fill the cavity 60. With the conductors 52,54 under tension, the force they have to separate the conductors 52, 54 places the fuse material 72 in compression. When the fuse material 72 is melted, the lock element moves as shown in Figure 8, in order to move on the lock element 62. As shown in Figures 9 and 10, the insurance member 66 it moves with the surface of the ramp 68 moving upwards and on the securing element 62 in order to allow the separation of the conductors 52, 54. While a preferred embodiment of the present invention has been illustrated and described, it will be evident that various changes and modifications will occur to those with experience in the art. Accordingly, it is intended in the appended claims to cover all those changes and modifications that fall within the true spirit and scope of the present invention.

Claims (10)

  1. NOVELTY OF THE INVENTION Having described the invention as above, we consider what is contained in the following: CLAIMS 1. A fuse element comprising two conductors and separable elements for releasing and securing said two separable conductors that includes interengaged parts surrounded by the fuse material, so that the forces separating the interengaged parts cause compressive forces in the fuse material, said interengaged parts comprise two separable conductors including respective interengaged parts so that relative movement between said interengaged parts is required before they can be separated. The fuse element of claim 1, wherein said fuse material is sufficiently softened to allow release and separation of said interengaged parts in response to a predetermined current-time condition. 3. A fuse element comprising two detachable conductors and a first element for removably securing said two separable conductors including interengaged parts surrounded by a fuse material so that the forces separating the interengaged parts cause the forces of compression in the fuse material, said interengaged parts of said first element comprise a safety lever mounted by a pivot carried by a first conductor of said two separable conductors and a second element carried by the second conductor of said two separable conductors to cooperate with said securing lever so that said safety lever in a first position retains said second element, and said safety lever by pivoting in said second position releases said second element. The fuse element of claim 3, wherein said lock lever includes a receiving groove and a first ramp surface having a first predetermined slope with respect to said receiving groove. 5. The fuse element of the claim 3, wherein said ramp surface is arranged to provide sufficient force to pivot said safety lever by the applied tension between the two separable conductors while minimizing the forces in the fuse material. 6. The fuse element of the claim 4, wherein said safety lever includes a second ramp surface having a predetermined inclination. The fuse element of claim 3, wherein said lock lever is pivotally mounted with respect to a pivot point, and along a first opposite surface of said receiving slot, tapers to reduce the projection of said safety lever of said safety lever away from said pivot point. The fuse element of claim 3, wherein said second element includes a hook portion cooperating with said lock lever. 9. A fuse element comprising two separable conductors, said first element carried by said two detachable conductors for releasably securing said two conductors, and the fuse material surrounding said first member, said first member comprising a second member transported by a first conductor of said two separable conductors and a third member carried by the second conductor of said two separable conductors, said second and third members comprises respective cooperating parts that are arranged in an interengaged relationship so that relative movement between said second conductor and third member allows separation of said two separable conductors. 10. The fuse element of the claim 9, wherein said fuse material is sufficiently softened to allow the release and separation of said two conductors in response to a predetermined current-time condition.
MXPA/A/1998/006682A 1997-08-19 1998-08-18 Fusi element MXPA98006682A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US08914574 1997-08-19

Publications (1)

Publication Number Publication Date
MXPA98006682A true MXPA98006682A (en) 1999-09-20

Family

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