Contact System Deflector Radial Finger Pre-Opening

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Solution Overview

Problem

Electrical switching devices at medium and high voltage levels face contact finger deformation due to high impact forces during closing and opening, leading to inadequate contact force and reduced robustness.

Innovation Solution

Incorporating a deflector that elastically deflects contact fingers radially outward before closing, reducing mechanical stress and maintaining required contact force by pre-opening the fingers before impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the closing speed of the rod is increased to improve switching performance, then the contact speed is improved, but the impact force on the arcing contact fingers increases causing permanent deformation

Engineering Contradiction:
Improvecontact speedVSAvoidcontact finger strength
Core Design Contradiction:
SpeedVSStrength

Solution Approach 1:

A deflector element is positioned to receive the rod before it contacts the arcing contact fingers. The deflector absorbs and distributes the impact force through elastic deformation, preventing direct transmission of the shock load to the contact fingers while allowing the rod to maintain its closing speed trajectory

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The deflector acts as an intermediary component between the rod and the arcing contact fingers. It mediates the interaction by converting the concentrated impact force into distributed elastic deformation, thereby protecting the contact fingers from permanent deformation while maintaining the kinetic energy transfer necessary for closing operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the contact force between arcing contact finger and second arcing contact is increased to ensure good electrical contact, then the electrical contact quality is improved, but the mechanical stress on the contact finger increases leading to deformation

Engineering Contradiction:
Improveelectrical contact reliabilityVSAvoidmechanical stress on contact finger
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The force transmission path is segmented into two independent stages: (1) the rod impacts the deflector which absorbs initial shock through elastic deformation, and (2) the deflector gradually transfers controlled force to the arcing contact fingers. This segmentation prevents concentrated stress while maintaining sufficient contact force for reliable electrical connection

Inventive Principle:
Principle #1Segmentation

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 approach minimizes mechanical strain on contact fingers, prolongs their lifespan, and ensures consistent electrical contact performance by reducing impact stress during the closing process.

Implementation Method 1

a deflector (7a) elastically deflecting the at least one contact finger (4a) in a radial direction away from the axis prior to or while closing the electrical switching device

Methodology Applied
Scientific EffectElastic deflection: Elasticity

Data Source

PatentEP2920801B1Contact system
Publication Date: 2016.09.07 ABB (SCHWEIZ) AG
  • EP2920801B1 patent drawingFigure 1
  • EP2920801B1 patent drawingFigure 2~3
  • EP2920801B1 patent drawingFigure 4~5

AI summary

The electrical switching device (1) has a longitudinal axis (z) and comprises at least one contact arrangement (4a, 4b), wherein the contact arrangement (4a, 4b) comprises a first contact (4a, 3a) and a mating second contact (4b, 3b), wherein the first contact comprises at least one contact finger (4a, 3a), wherein for closing and opening the electric switching device (1) at least one of the first contact and the mating second contact (3a, 3b; 4a, 4b) is movable parallel to the longitudinal axis (z) and cooperates with the other contact (3b, 3a; 4b, 4a), characterized in that the electrical switching device further comprises a deflector (6; 7a; 11, 14) elastically deflecting the at least one contact finger (3a, 4a) in a radial direction away from the axis (z) prior to or while closing the electrical switching device ( 1 ).