Switching Device Contact Assembly with Segmented Conductive Members

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Solution Overview

Problem

In switching devices, the erosion of metal copper contacts due to arcing during contact separation leads to malfunction and reduced service life.

Innovation Solution

A contact assembly with first conductive members made of arc-resistant materials like steel and second conductive members made of copper, where the first members have superior arc erosion resistance, and a barrier member with a contact projection to manage contact spacing and reduce friction, effectively minimizing arc erosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal copper contacts are used to reduce on-resistance, then electrical conductivity is improved, but arc erosion resistance deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoidarc erosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The contact assembly is divided into multiple conductive members (first conductive member, second conductive member, third conductive member) with different materials and functions. The first conductive member contacts the fixed contact during normal operation, while the second and third members serve as backup contacts, segmenting the contact function to reduce erosion on any single contact surface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the contact assembly have different material properties optimized for their specific functions. The first conductive member uses material with superior arc erosion resistance for the primary contact interface, while maintaining good electrical conductivity through the copper-based second and third conductive members.

Inventive Principle:
Principle #3Local quality

2Productivity

If the moveable contact is separated from the fixed contact to break the circuit, then current interruption is achieved, but arc erosion increases

Engineering Contradiction:
Improvecurrent interruption capabilityVSAvoidcontact material erosion
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The second and third conductive members are pre-positioned as backup contacts that can engage if the primary first conductive member becomes eroded or fails. This preliminary arrangement ensures continuous operational capability and reduces the frequency of complete contact replacement.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The multi-member contact system allows the system to discard (ignore) the eroded first conductive member and recover functionality through the second and third conductive members, extending the overall service life of the switching device.

Inventive Principle:
Principle #34Discarding and recovering

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 contact assembly significantly reduces contact erosion, extending the service life of switching devices by using steel for arc-resistant areas and copper for conductive areas, and optimizing contact geometry to manage arc energy and friction.

Implementation Method 1

the arc erosion resistance performance of the first conductive members is superior than that of the second conductive members

Methodology Applied
Scientific EffectArc erosion resistance: Arc Evaporation

Implementation Method 2

an elastic force applied to the first conductive members by the elastic pieces tending to narrow the spacing between the first conductive members and the spacing between the second conductive members

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP2913834B1Contact assembly of switching device and switching device thereof
Publication Date: 2016.11.09 SIEMENS AG
  • EP2913834B1 patent drawingFigure 1
  • EP2913834B1 patent drawingFigure 2~3
  • EP2913834B1 patent drawingFigure 4~5

AI summary

A contact assembly of a switching device, comprising a fixed contact member (10) and a moveable contact component (20). The moveable contact component comprises a pair of first conductive members (22) and a pair of second conductive members (24). The first conductive members have contact ends (222). The second conductive members are provided between the first conductive members. The fixed contact member may contact the contact ends or the second conductive members, and the arc erosion resistance performance of the first conductive members is poorer than that of the second conductive members, and when the second conductive members are out of contact with the fixed contact member, the contact ends may contact the fixed contact member. In the contact assembly of the switching device, when the moveable contact component is separated from the fixed contact member, an arc is produced between the first conductive members and the fixed contact member, and the first conductive members have arc erosion resistance performance superior to that of the second conductive members; therefore, erosion of the contacts by the arc can be effectively reduced, and the service life of the switching device is extended.