Circuit Breaker Core Geometry for Asymmetrical Magnetic Actuation

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Solution Overview

Problem

Existing circuit breaker mechanisms for high current bus bars lack asymmetrical characteristics, leading to symmetrical behavior regardless of current direction, and require higher activation currents.

Innovation Solution

The design incorporates a core with a specific configuration of yokes, air gaps, and permanent magnets in the second yoke and movable armature, which alters the magnetic flux directionally to create asymmetrical characteristics, reducing the activation current and enabling unidirectional operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If permanent magnets are added to create asymmetrical magnetic flux, then activation current is reduced and unidirectional operation is enabled, but device complexity increases

Engineering Contradiction:
Improveactivation currentVSAvoiddevice complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by introducing permanent magnets into one of the yokes (second yoke) to create asymmetrical magnetic flux distribution. This asymmetry causes the magnetic flux to be amplified in one current direction and attenuated in the opposite direction, enabling unidirectional operation and reducing activation current for that direction.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The permanent magnets act as intermediaries that modify the magnetic flux path and intensity. By placing permanent magnets in the second yoke, the system leverages their magnetic field to amplify flux in the desired direction and attenuate it in the opposite direction, thereby reducing the activation current requirement without requiring complete redesign of the circuit breaker mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If permanent magnets are added to amplify magnetic flux in one direction, then unidirectional operation is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improveunidirectional operationVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent implements unidirectional operation by creating an asymmetrical configuration where permanent magnets are installed in only one yoke (the second yoke) rather than both. This asymmetrical placement allows the circuit breaker to differentiate between current directions, achieving unidirectional protection capability while maintaining compatibility with existing circuit breaker mechanisms.

Inventive Principle:
Principle #4Asymmetry

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 solution achieves asymmetrical characteristics in circuit breaker mechanisms, allowing for lower activation currents and unidirectional operation, while being compatible with existing circuit breaker mechanisms.

Implementation Method 1

generate a unidirectional unique magnetic flux inside the main frame and the movable core, the said magnetic flux creating a first force on the movable core that tends to maintain it in its first position

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 2

the said magnetic flux creating a first force on the movable core that tends to maintain it in its first position

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Implementation Method 3

a first current flowing through the main frame and generating a first flux inside the main frame and the movable core in the same direction as the magnetic flux exceeds a first limit value

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4564394A1Core for circuit breaker mechanism and circuit breaker mechanism
Publication Date: 2025.06.04 ABB (SCHWEIZ) AG
  • EP4564394A1 patent drawingFigure 1
  • EP4564394A1 patent drawingFigure 2
  • EP4564394A1 patent drawingFigure 3

AI summary

The invention relates to a core for a circuit breaker mechanism and a circuit breaker mechanism designed for a high current bus bars. A core for a circuit breaker mechanism comprising: a first limb (2), a second limb (3), a first yoke (4), a second yoke (5), a third yoke (6); wherein between the first limb (2) and the second limb (3) there are the first yoke (4), the second yoke (5) and the third yoke (6), wherein the third yoke (6) has a smaller cross-section area then the second yoke (5), wherein the second yoke (5) comprises a first air gap (7) and at least one opening (9), where edges (10) of the first air gap (7) are tilted such that the first air gap (7) forms a trapezoid, and wherein the third yoke (6) comprises a second air gap (8).