Arc-extinguishing composition and articles manufactured therefrom

Abstract

An arc-interrupting compound, such as melamine, and to a method of extinguishing an arc by disposing the composition along the path of the arc, for contacting the arc. In one embodiment, the binder, or at least a portion of the binder, is a polymer that contains a functional group that binds to a coupling agent that is included in the arc-extinguishing composition. The coupling agent ties the polymeric binder to the arc-extinguishing compound, e.g., melamine, to provide new and unexpected physical strength and stability to the composition. In this embodiment, the molded composition, including the arc-interrupting compound coupled to the binder, maintains excellent arc-interrupting capability, while providing chemical stability and electrical insulating properties as well as unexpected physical strength.

Description

FIELD

[0001] The present invention relates to arc-quenching materials and articles fabricated therefrom for high-voltage electrical devices and equipment such as circuit interrupters wherein, under certain conditions of operation, a high-voltage electrical arc is produced that is either desirably, or by necessity, quenched. More particularly, the present invention relates to a composition to achieve arc-quenching and structural properties in devices such as circuit interrupters, high-voltage fuses, circuit breakers, and separable cable connectors. BACKGROUND AND PRIOR ART

[0002] To provide effective circuit interruption in circuit interrupters, fuses, and the like, it is desirable to utilize an arc-quenching material or composition to quench and suppress arcing during electrical contact separation or fuse operation. Of necessity, the arc-quenching materials should include characteristics and properties sufficient for the particular application so as to be effective in quenching arcs...

Examples

second embodiment

[0067] In accordance with the arc-extinguishing compositions, articles and methods described herein, it has been found that when the arc-extinguishing compound is provided in finely divided form (see Table 2 and FIG. 4), the molded arc-extinguishing composition has unexpectedly increased toughness, and especially elongation, thereby preventing breakage of the molded articles.

[0068] In accordance with the second embodiment, wherein the arc-extinguishing compound is provided in finely divided form, it has been found that the compound should have a particle size distribution such that at least 90% by weight, up to 100%, of the particles have a size less than about 200 microns (μm). Preferably, at least 90% by weight of the particles have a particle size less than about 100 μm and, more preferably, at least 99% by weight of the arc-extinguishing compound particles have a particle size less than 100 μm. To achieve the full advantage of this second embodiment of the compositions, articles...

third embodiment

[0069] In accordance with the compositions, articles and methods described herein, it has been found that by including a plasticizer for the binder polymer into the compositions, the structural properties of the molded articles are increased without sacrificing arc-extinguishing properties.

[0070] To determine which plasticizer(s) is suitable for a particular polymer binder, compatible plasticizers should have a solubility parameter (δ) suitable for the particular polymeric binder, as well known in the art. One method of determining solubility parameters (δ) is in accordance with ASTM Designation D-3132-84 (Re-approved 1990). The plasticizer for the polymeric binders should have a solubility parameter (δ) as close as possible to the solubility parameter of the polymeric binder. For example, some of the preferred polyamide (nylon) polymeric binders have solubility parameters (δ) as follows:

Preferred δ forδ for ε-δ for binderplasticizercaprolactamNylon 6: δ = 12.8311.5-14.012.7Nylon ...

FIELD

[0001] The present invention relates to arc-quenching materials and articles fabricated therefrom for high-voltage electrical devices and equipment such as circuit interrupters wherein, under certain conditions of operation, a high-voltage electrical arc is produced that is either desirably, or by necessity, quenched. More particularly, the present invention relates to a composition to achieve arc-quenching and structural properties in devices such as circuit interrupters, high-voltage fuses, circuit breakers, and separable cable connectors. BACKGROUND AND PRIOR ART

[0002] To provide effective circuit interruption in circuit interrupters, fuses, and the like, it is desirable to utilize an arc-quenching material or composition to quench and suppress arcing during electrical contact separation or fuse operation. Of necessity, the arc-quenching materials should include characteristics and properties sufficient for the particular application so as to be effective in quenching arcs...

Examples

second embodiment

[0067] In accordance with the arc-extinguishing compositions, articles and methods described herein, it has been found that when the arc-extinguishing compound is provided in finely divided form (see Table 2 and FIG. 4), the molded arc-extinguishing composition has unexpectedly increased toughness, and especially elongation, thereby preventing breakage of the molded articles.

[0068] In accordance with the second embodiment, wherein the arc-extinguishing compound is provided in finely divided form, it has been found that the compound should have a particle size distribution such that at least 90% by weight, up to 100%, of the particles have a size less than about 200 microns (μm). Preferably, at least 90% by weight of the particles have a particle size less than about 100 μm and, more preferably, at least 99% by weight of the arc-extinguishing compound particles have a particle size less than 100 μm. To achieve the full advantage of this second embodiment of the compositions, articles...

third embodiment

[0069] In accordance with the compositions, articles and methods described herein, it has been found that by including a plasticizer for the binder polymer into the compositions, the structural properties of the molded articles are increased without sacrificing arc-extinguishing properties.

[0070] To determine which plasticizer(s) is suitable for a particular polymer binder, compatible plasticizers should have a solubility parameter (δ) suitable for the particular polymeric binder, as well known in the art. One method of determining solubility parameters (δ) is in accordance with ASTM Designation D-3132-84 (Re-approved 1990). The plasticizer for the polymeric binders should have a solubility parameter (δ) as close as possible to the solubility parameter of the polymeric binder. For example, some of the preferred polyamide (nylon) polymeric binders have solubility parameters (δ) as follows:

Preferred δ forδ for ε-δ for binderplasticizercaprolactamNylon 6: δ = 12.8311.5-14.012.7Nylon ...

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