Arc Chamber Composite Plates for Low-Voltage Circuit Breakers

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Solution Overview

Problem

Low voltage circuit breakers face challenges in withstanding thermal and mechanical stresses during electrical arcs, leading to damage and the need for frequent replacement of arc-breaking metal plates, with existing solutions failing to adequately insulate and prevent arc escape.

Innovation Solution

Incorporating arc-breaking plates made of a combination of ferromagnetic and ceramic materials, where the peripheral region is ferromagnetic and the central region is ceramic, to enhance insulation and thermal resistance, reducing ablation and melting of plates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If ferromagnetic material is used for arc-breaking plates, then magnetic blowing effect is improved, but thermal resistance and insulation are insufficient causing plate melting and damage

Engineering Contradiction:
Improvemagnetic blowing effectVSAvoidthermal resistance
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The arc-breaking plate is constructed as a composite structure with a ferromagnetic substrate providing magnetic blowing effect and a ceramic coating layer providing thermal resistance and insulation. This composite material approach allows simultaneous achievement of strong magnetic field interaction and high temperature withstand capability, resolving the contradiction between magnetic effect and thermal resistance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If traditional metal plates are used in arc chamber, then magnetic and electrical performance is maintained, but ablation and melting occur under high thermal stress

Engineering Contradiction:
Improvemagnetic and electrical performanceVSAvoidresistance to ablation and melting
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The combination of ferromagnetic material and ceramic coating creates a composite plate that maintains the magnetic properties needed for arc control while the ceramic layer provides exceptional resistance to ablation and melting under high thermal stress, significantly improving reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The ceramic coating is applied specifically to the surfaces directly exposed to the arc, providing localized thermal protection where it is most needed, while the ferromagnetic substrate maintains the overall magnetic field generation capability.

Inventive Principle:
Principle #3Local quality

3Speed

If arc chamber design is optimized for rapid interruption, then opening speed is improved, but thermal and mechanical stresses increase causing damage to components

Engineering Contradiction:
Improveopening speedVSAvoidthermal and mechanical stresses
Core Design Contradiction:
SpeedVSStress or pressure

Solution Approach 1:

The ceramic-coated ferromagnetic plates can withstand the intensified thermal and mechanical stresses resulting from rapid opening operations, as the ceramic layer protects against thermal shock and mechanical wear while allowing fast operation to be maintained.

Inventive Principle:
Principle #40Composite materials

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 use of ceramic and ferromagnetic materials in the arc chamber effectively withstands electrical and magnetic effects, reduces plate damage, and maintains insulation, minimizing the need for maintenance and plate replacements while maintaining magnetic and electrical performance.

Implementation Method 1

arc-breaking plates made of a combination of ferromagnetic and ceramic materials, where the peripheral region is ferromagnetic and the central region is ceramic

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

enhance insulation and thermal resistance, reducing ablation and melting of plates

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 3

The very high temperatures that develop during arching phenomena can lead to melting and damages of the arc-breaking metal plates arranged in the chamber

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 4

The very high temperatures that develop during arching phenomena can lead to melting and damages of the arc-breaking metal plates arranged in the chamber

Methodology Applied
Scientific EffectAblation: Ablation

Implementation Method 5

During arc forming, the energy released by Joule effect is very high and causes thermal and mechanical stresses inside the plate containment region

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3557599B1Low-voltage circuit breaker
Publication Date: 2024.01.10 ABB SPA
  • EP3557599B1 patent drawingFigure 1
  • EP3557599B1 patent drawingFigure 2
  • EP3557599B1 patent drawingFigure 3

AI summary

A low-voltage circuit breaker comprising one or more electrical poles, each of said poles having an internal space with a contact area and an arc extinguishing area, a fixed contact assembly and a movable contact assembly being positioned in said contact area, said movable contact assembly being movable between a closed position in which it is into contact with said fixed contact assembly and an open position in which it is spaced apart from said fixed contact assembly, an arc chamber comprising a plurality of substantially parallel arc-breaking plates made of a ferromagnetic material being positioned in said arc extinguishing area. The low-voltage circuit breaker is characterized in that said arc chamber further comprises at least one arc-breaking plate which is at least partially made of a ceramic material.