Wear-Contact Switch Structure to Prevent Arc Damage

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Solution Overview

Problem

High-voltage rail vehicle switches experience reduced lifespan and operational issues due to the formation of electric arcs between the arm and the second terminal, leading to material removal and alteration.

Innovation Solution

The implementation of a switch design with wear contacts that come into contact with each other in an intermediate position, preventing electric arcs between the arm and the second terminal by maintaining contact until the switch is fully closed or opened.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the switch operates at high voltage (15000V to 25000V), then the switch can supply electrical power to railway vehicles, but electric arcs form between the arm and the second terminal causing material removal and reduced lifespan

Engineering Contradiction:
Improveelectrical power supply capabilityVSAvoidswitch lifespan
Core Design Contradiction:
PowerVSDuration of action of stationary object

Solution Approach 1:

The patent introduces wear contacts as intermediary elements between the arm and the second terminal. These wear contacts serve as a sacrificial mediator that absorbs the harmful electric arc effects, protecting the main terminal from material removal and deterioration while allowing the switch to continue operating at high voltage

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If the arm and second terminal are kept close to each other, then the switch can close quickly for efficient power connection, but electric arcs are more likely to cause material removal and deterioration

Engineering Contradiction:
Improveswitch closing speedVSAvoidmaterial removal from arm and terminal
Core Design Contradiction:
SpeedVSLoss of substance

Solution Approach 1:

The wear contacts are positioned between the arm and the second terminal, serving as a protective intermediary layer. This allows the arm and terminal to maintain close proximity for fast switching while the wear contacts absorb the arc-induced material loss, preventing direct deterioration of the main terminal components

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the switch structure is simplified without wear contacts, then the device complexity is reduced, but the service life of the switch is significantly reduced due to direct arc exposure

Engineering Contradiction:
Improveswitch structure complexityVSAvoidswitch service life
Core Design Contradiction:
Device complexityVSDuration of action of moving object

Solution Approach 1:

The wear contacts are designed as sacrificial, replaceable components that are intentionally made to wear down over time. These relatively simple, short-lived elements protect the more critical and expensive main terminal components, extending the overall switch service life while maintaining structural simplicity

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 significantly reduces wear on the arm and second terminal, thereby extending the lifespan of the switch and ensuring reliable operation by eliminating electric arcs during switching.

Implementation Method 1

opening or closing the switch causes the appearance of one or more electric arcs between the arm and the second terminal

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Data Source

PatentEP3839998B1Electric switch with wear contacts
Publication Date: 2025.04.02 ALSTOM HOLDINGS SA
  • EP3839998B1 patent drawingFigure 1
  • EP3839998B1 patent drawingFigure 2
  • EP3839998B1 patent drawingFigure 3

AI summary

An electrical switch (18) comprising: - a first terminal (22) and a second terminal (24) suitable for electrical connection to a first electrical circuit (14) and a second electrical circuit (16), and - an arm (26) electrically connected to the first terminal (22), and movable relative to the second terminal (24) between a closed position of the switch and an open position of the switch. The switch includes a first wear contact (28) and a second wear contact (32) electrically and mechanically connected respectively to the arm by a first connection system (30), and to the second terminal by a second connection system (34).The arm is mobile successively between the open position, in which the first wear contact is away from the second wear contact to avoid an electric arc between the first and second wear contacts, an intermediate position, in which the first wear contact is in electrical contact with the second wear contact, notably via an electric arc, while the arm and the second terminal are still away from each other to avoid an electric arc between the arm and the second terminal, and the closed position.