High-Current Contactor Layout Using Attractive Lorentz Force

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Solution Overview

Problem

Existing electrical contactors experience separation of contact tips due to anti-parallel current flow, leading to undesired electrical arcs during high current conditions, which existing solutions fail to adequately address.

Innovation Solution

The electrical contactor system is designed with fixed and moving contacts shaped to generate an additional Lorentz force that counteracts separation forces by conducting current in parallel, using overlapping sections to attract the contact tips through symmetrical arrangements of fixed and moving bars.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contact springs are used to ensure contact force, then contact reliability is improved at low currents, but contact separation occurs at high currents when separation force exceeds spring force

Engineering Contradiction:
Improvecontact reliabilityVSAvoidseparation force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent converts the harmful repulsive Lorentz force into a beneficial attractive Lorentz force by changing the current flow configuration. Instead of anti-parallel current flow through contact tips, the design uses parallel current flow through overlapping bar sections, transforming the separation force into an attraction force that maintains contact under high current conditions.

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

Solution Approach 2:

The patent changes the physical configuration parameter of the current path from anti-parallel through contact tips to parallel through overlapping bar sections. This parameter change fundamentally alters the direction of the Lorentz force from repulsive to attractive, enabling the contactor to handle high currents without separation.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If contact tips are used for current transmission, then electrical connection is achieved, but surface roughness causes current constriction to few points

Engineering Contradiction:
Improveelectrical connectionVSAvoidsurface flatness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent extracts the current transmission function from the contact tips themselves and relocates it to the overlapping bar sections. By guiding current through the parallel overlapping sections of the bars, the design bypasses the surface roughness issue at the contact tips while still achieving reliable electrical connection.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If overlapping sections are designed to generate attractive Lorentz force, then contact separation is prevented, but device complexity increases

Engineering Contradiction:
Improvecontact stabilityVSAvoidbar configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The overlapping bar sections serve multiple functions simultaneously: they provide the current path for high current transmission, generate the attractive Lorentz force to prevent separation, and maintain mechanical alignment between fixed and moving contacts. This multi-functionality reduces the need for additional components.

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

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 design effectively prevents contact tip separation by generating an attractive Lorentz force greater than the repulsive force, ensuring stable contact at high currents and reducing the risk of electrical arcs.

Implementation Method 1

the first fixed bar and the moving bar are configured to guide current in the same direction in the overlapping sections

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 2

according to Ampere's law of force an additional Lorentz force is generated

Methodology Applied
Scientific EffectAmpere's law of force: Ampère's Force Law

Data Source

PatentEP3979279B1Electrical contactor
Publication Date: 2026.04.08 ABB (SCHWEIZ) AG
  • EP3979279B1 patent drawingFigure 1a~1d
  • EP3979279B1 patent drawingFigure 2a~2c
  • EP3979279B1 patent drawingFigure 3a~3b

AI summary

The present invention relates to an electrical contactor for high current applications, an electrical contactor system comprising at least two electrical contactors, and the use such an electrical contactor. The electrical contactor (200) for high current applications, comprising a first fixed bar (202), a moving bar (206), and first electrical contact tips (210) arranged between the first fixed bar (202) and the moving bar (206) electrically connecting the first fixed bar (202) with the moving bar (206). The first fixed bar (202) and the moving bar (206) comprise overlapping sections (230) arranged in parallel to each other, and the first fixed bar (202) and the moving bar (206) are configured to guide current in the same direction in the overlapping sections (230).