Overcurrent Tripping Mechanism With Single-Axis Armature Motion

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Solution Overview

Problem

The existing tripping mechanism in overcurrent tripping units experiences additional friction and strain due to shifted axes, affecting the breaker's high-speed opening and low-current tripping ability.

Innovation Solution

A tripping mechanism with a magnetic core, yokes, a leading rod, a spring, and a tripping lever, where the leading rod is fixed relative to the magnetic core, and a spring forces the armature towards the first yoke, eliminating momentum and friction by transferring movement along a single axis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the tripping rod axis is shifted by certain distance from the leading rod axis, then the tripping force can be transmitted from the armature to the tripping lever, but additional friction and strain are created between the armature and leading rod

Engineering Contradiction:
Improvetripping force transmissionVSAvoidadditional friction
Core Design Contradiction:
ForceVSLoss of energy

Solution Approach 1:

The patent introduces a magnetic core as an intermediary element that couples the armature and leading rod through magnetic fields. The magnetic core with yokes creates a magnetic circuit that allows force transmission without direct mechanical contact between the armature and leading rod, thereby eliminating friction while maintaining force transmission capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the direct mechanical connection between the armature and leading rod with a magnetic field-based connection. The magnetic core, armature, and leading rod form a magnetic circuit where electromagnetic forces are generated, substituting the mechanical friction-based force transmission with a field-based interaction that eliminates contact friction

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If the tripping rod axis is shifted by certain distance from the leading rod axis, then the tripping mechanism can activate the tripping lever, but additional strain requires additional armature stroke

Engineering Contradiction:
Improvetripping lever activationVSAvoidarmature stroke
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The magnetic core serves as a mediator that distributes and transmits forces efficiently through its magnetic circuit. The yokes and magnetic path allow the armature's movement to be converted into effective tripping force without requiring excessive stroke, as the magnetic field efficiently couples the motion to the leading rod

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs curved sections in the tripping lever and optimized magnetic path geometries to improve force transmission efficiency. The curved geometry of the tripping lever helps convert the armature's linear motion into effective rotational or lateral movement with reduced stroke requirements

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of operation

If the tripping rod drives the tripping lever with shifted axes, then the breaker can be opened, but the high-speed opening ability is adversely impacted

Engineering Contradiction:
Improvebreaker opening capabilityVSAvoidhigh-speed opening ability
Core Design Contradiction:
Ease of operationVSSpeed

Solution Approach 1:

The patent replaces the mechanical friction-based force transmission system with an electromagnetic force transmission system. The magnetic core and magnetic circuit enable rapid force transmission without the inertia and friction constraints of direct mechanical contact, allowing high-speed breaker opening

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic core acts as a high-speed force transmission intermediary that responds rapidly to armature movement. The magnetic field establishes and collapses quickly, enabling fast tripping action without the mechanical lag associated with friction-based systems

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This configuration enhances the breaker's high-speed opening and low-current tripping capability by minimizing additional friction and strain, improving operational efficiency.

Implementation Method 1

The spring is configured to force the armature towards the first yoke

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

magnetic core with a first yoke, a second yoke and a third yoke, wherein the third yoke comprising a yoke through hole, an armature comprising an armature through hole

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP4618126A1Tripping mechanism
Publication Date: 2025.09.17 ABB (SCHWEIZ) AG
  • EP4618126A1 patent drawingFigure 1
  • EP4618126A1 patent drawingFigure 2
  • EP4618126A1 patent drawingFigure 3

AI summary

The invention relates to a tripping mechanism, suitable for use in an overcurrent tripping unit, designed for a high current bus bars. A tripping mechanism, suitable for use in an overcurrent tripping unit, comprising: a magnetic core (1) with a first yoke (2a), a second yoke (2b) and a third yoke (2c), wherein the third yoke (2c) comprising a yoke through hole, an armature (3) comprising an armature through hole, a leading rod (4) with a fixing means, a spring (6) and means for tensioning the spring (6), a tripping lever (9), means for transferring a movement of the armature (3), wherein the armature (3) is movably placed between the first yoke (2a) and the second yoke (2b), wherein the leading rod (4) extends throughout the magnetic core (1), namely between arms of the first yoke (2a), the second yoke (2b), the yoke through hole of the third yoke (2c), and the armature (3), namely through the armature through hole, while the leading rod (4) position is fixed, in relation to the magnetic core (1), with the fixing means, wherein the leading rod (4) is placed inside the spring (6) and the spring (6) is placed between the armature (3) and the means for tensioning, wherein the spring (6) extends through the yoke through hole of the third yoke (2c), wherein the spring (6) is configured to push the armature (3) towards the first yoke (2a), wherein the means for transferring a movement of the armature (3) are placed inside the yoke through hole of the third yoke (2c) and outside the spring (6) and are configured to transfer a movement of the armature (3) between the first yoke (2a) and the second yoke (2b) to the tripping lever (9).