Medium-Voltage Vacuum Contact With Ceramic Spacer

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Solution Overview

Problem

Vacuum interrupters face challenges in withstanding high compression forces during closing maneuvers and in maintaining the closed position under high current conditions, leading to potential contact collapse and increased dimensions for effective arc breaking in medium voltage applications.

Innovation Solution

The design incorporates a metal tube filled with ceramic material as spacers between the contact body and the mechanical connection part, providing mechanical reinforcement while maintaining high electrical resistivity, ensuring minimal current flow through the spacers and preventing collapse, with a configuration of multiple columns distributed at 120° on the circumference to enhance mechanical strength and resistivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contact diameter is increased to break high short-circuit currents, then arc breaking performance is improved, but contact collapse risk increases under compression forces

Engineering Contradiction:
Improvearc breaking performanceVSAvoidcontact mechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The contact structure uses a composite design combining copper (high electrical conductivity) and stainless steel (high mechanical strength). The copper core handles electrical current while the stainless steel reinforcement provides structural support to prevent collapse under compression forces, enabling large diameter contacts to maintain both electrical performance and mechanical integrity

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The contact is divided into distinct functional segments: a copper core for electrical conduction and a stainless steel reinforcement layer for mechanical support. This segmentation allows each material to optimize its specific function while working together as an integrated contact structure

Inventive Principle:
Principle #1Segmentation

2Reliability

If contact diameter is increased to break high short-circuit currents, then arc breaking performance is improved, but vacuum interrupter dimensions and cost increase

Engineering Contradiction:
Improvearc breaking performanceVSAvoidvacuum interrupter dimensions
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The composite contact structure enables more efficient use of contact material by combining high-conductivity copper with high-strength stainless steel. This allows achieving the required mechanical strength and arc breaking performance with optimized contact dimensions, preventing unnecessary increases in vacuum interrupter size

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If compression forces are increased to maintain closed position under high current, then contact stability is improved, but contact collapse risk increases during closing maneuver

Engineering Contradiction:
Improvecontact stabilityVSAvoidcontact resistance to compression
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The stainless steel reinforcement provides high compressive strength to withstand the 2-tonne force peak during closing maneuver, while the copper core maintains electrical conductivity. This composite structure enables the contact to resist compression forces without collapsing during the closing operation

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The reinforced contact structure is designed in advance to withstand the expected compression forces during closing maneuver. The stainless steel reinforcement acts as a pre-built structural support system that prevents collapse before it can occur during the high-stress closing operation

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

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 effectively prevents contact collapse under high compressive forces and maintains electrical integrity by minimizing current flow through the spacers, allowing for the use of larger contact diameters without compromising mechanical strength or electrical performance.

Implementation Method 1

a first hollow cylinder which comprises slots made in a spiral around its axis and opening at least on its exterior, said first hollow cylinder being centered on the longitudinal axis Y with one end secured to the mechanical connection part, the hollow of the first cylinder being devoid of material, the first cylinder constituting a first winding adapted to generate a magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2264732B1Contact for medium-voltage vacuum bottle with strengthened structure, vacuum bottle and circuit breaker, such as an associated generator circuit breaker
Publication Date: 2014.12.10 SCHNEIDER ELECTRIC ENERGY FRANCE
  • EP2264732B1 patent drawingFigure 1
  • EP2264732B1 patent drawingFigure 2~3

AI summary

The invention relates to a new vacuum ampoule design in which at least one of the contacts incorporates a spacer between the mechanical connection and the circular plate of the contact body, preventing the latter from collapsing during the closing of the vacuum ampoule and in this closed position. The invention enables the contacts to withstand very high compressive forces, typically exceeding 700 kg-force and even reaching 2 tonnes-force.