Arc Chute Debris Barrier for Circuit Breaker Reliability

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Solution Overview

Problem

Electrical switching apparatus, such as circuit breakers, face challenges in managing debris generated by arcs between contacts, which can accumulate in critical areas and cause malfunctions.

Innovation Solution

A debris barrier made from thermoset material, designed as a unitary component with a U-shaped structure, redirects debris away from critical areas by incorporating splitter plates and laminations, effectively preventing accumulation and ensuring the circuit breaker's longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If arc extinguishing devices with multiple splitter plates are used to manage arcs between contacts, then arc extinction effectiveness is improved, but debris generation and accumulation in critical areas increases

Engineering Contradiction:
Improvearc extinction effectivenessVSAvoiddebris generation and accumulation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent redirects the harmful debris generated by arc extinction between splitter plates into a designated debris containment area. The barrier member with debris redirecting surfaces captures debris that would otherwise accumulate in critical functional areas, converting the harmful effect of debris generation into a controlled containment scenario that protects the circuit breaker's reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If a debris barrier is added to redirect debris away from critical areas, then reliability is improved by preventing debris accumulation, but device complexity increases

Engineering Contradiction:
Improveprotection from debris accumulationVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The barrier member is integrated with the arc chute assembly, combining the debris barrier function with the existing arc extinction structure. The barrier member works cooperatively with the splitter plates and arc chute to provide both arc extinction and debris redirection functions within a unified structural arrangement, minimizing additional complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The barrier member serves multiple functions: it redirects debris away from critical areas, defines a debris containment area, and works in conjunction with the arc chute assembly for arc extinction. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If a unitary molded barrier member is used to simplify manufacturing, then ease of manufacture is improved, but adaptability to different arc chute configurations is reduced

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidadaptability to arc chute configurations
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The barrier member is designed with adjustable parameters including the orientation and angle of the debris redirecting surfaces, the dimensions of the debris containment area, and the overall geometry of the barrier. These parameters can be modified to adapt to different arc chute configurations while maintaining the unitary molded construction that provides manufacturing simplicity.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The debris barrier effectively redirects debris generated during arcing, minimizing the risk of malfunctions and prolonging the circuit breaker's life by preventing debris accumulation in critical functional areas.

Implementation Method 1

A debris barrier made from thermoset material, designed as a unitary component with a U-shaped structure, redirects debris away from critical areas by incorporating splitter plates and laminations

Methodology Applied
Scientific EffectPhysical barrier redirection:

Implementation Method 2

EP 2 717 288 A1 discloses generating a magnetic flux between pairs of grid leg portions of a plurality of magnetic grids configuring an arc extinguishing device in a direction perpendicular to an arc generated between a fixed contact point of a fixed contact and a movable contact point of a movable contact, and permanent magnets causing an electromagnetic force to act so that the arc moves to a grid base portion side

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 3

US 2009/200272 A1 discloses an arc-extinguishing processed resin article, and a circuit breaker that uses this arc-extinguishing processed resin article. The circuit breaker uses, as the arc-extinguishing device, an arc-extinguishing processed resin article obtained by molding a resin composition containing (A) polyolefin resin that has the hydroxyl group substituted for a portion of the hydrogen atoms in the methylene chain and that contains 0.2 to 0.7 mole hydroxyl group per mole methylene group, (B) a crosslinking agent that has a terminal unsaturated group, and (C) metal hydroxide whose surface has been treated with higher aliphatic acid, wherein the resin composition contains 5 to 60 mass parts of the metal hydroxide (C) per 100 mass parts of the polyolefin resin (A), and radiation-induced crosslinking is executed on the resin composition after the molding thereof

Methodology Applied
Scientific EffectRadiation-induced crosslinking:

Data Source

PatentEP3655979B1Electrical switching apparatus and debris barrier therefor
Publication Date: 2024.10.16 EATON INTELLIGENT POWER LTD
  • EP3655979B1 patent drawingFigure 1
  • EP3655979B1 patent drawingFigure 2
  • EP3655979B1 patent drawingFigure 3

AI summary

A debris barrier (50, 250, 350) is for an electrical switching apparatus (2, 202, 302). The electrical switching apparatus includes separable contacts (12, 14) and an arc chute (16). The separable contacts generate debris when tripping open in response to an electrical fault. The arc chute has a plurality of splitter plates (18, 218) each having an edge portion (20) and a distal portion (22, 24, 222, 224) located opposite and distal the edge portion. The debris barrier includes a first leg (52, 252, 352), a second leg (54, 254, 354), and a middle portion (56, 356) connecting the first leg and the second leg. The middle portion is coupled to one of the separable contacts. At least one of the first leg and the second leg has a first barrier portion (58, 60, 358, 360) and a second barrier portion (62, 64, 262, 264, 362, 364) extending therefrom. The first barrier portion is located proximate the distal portion. The second barrier portion extends from the first barrier portion toward the edge portion in order to redirect the debris toward the edge portion.