Spring-Loaded Contact Elements for High Voltage Switches

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Solution Overview

Problem

Existing high or medium voltage switches, particularly DC switches, face challenges in simplifying the assembly of conducting elements onto their carriers and improving the carrier material for enhanced performance and reliability.

Innovation Solution

The switch design features a first and second set of contact elements with insulating carriers and spring-loaded pins for secure mounting, allowing for a glue-free connection and improved current conduction, using a carrier frame made from epoxy material reinforced with aramid fibers for superior performance, and conducting elements made from high conductivity materials with rounded edges for reduced electrical field exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conducting elements are mounted onto carriers using traditional methods (glue or mechanical fastening), then the connection is secure, but the assembly process is complex and time-consuming

Engineering Contradiction:
Improveassembly simplicityVSAvoidmounting mechanism complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The conducting element is segmented into a main body and separate contact faces, allowing the contact faces to be independently positioned and secured using spring-loaded pins. This segmentation enables simplified assembly where components can be independently manufactured and then easily combined without complex mounting procedures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring-loaded pins automatically secure the conducting elements to the carriers through elastic engagement. The pins are resiliently mounted in recesses and automatically engage with the conducting elements, eliminating the need for external fastening mechanisms or complex assembly procedures. The system self-secures through the inherent elasticity of the pins.

Inventive Principle:
Principle #25Self-service

2Loss of energy

If conducting elements have sharp edges, then manufacturing is simpler, but electrical field exposure increases causing higher loss of energy

Engineering Contradiction:
Improveelectrical field exposureVSAvoidmanufacturing complexity
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The contact faces of the conducting elements are designed with rounded edges and curved surfaces instead of sharp edges. This curvature reduces electrical field concentration at the contact points, minimizing energy loss and improving electrical performance. The rounded geometry is directly formed during manufacturing, adding minimal complexity to the fabrication process.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Loss of substance

If conducting elements are rigidly fixed to carriers, then positioning is precise, but the connection creates hetero-material interfaces increasing loss of substance

Engineering Contradiction:
Improvematerial interactionVSAvoidpositioning precision
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The spring-loaded pins are made from the same material as the conducting elements, creating a homogeneous connection without hetero-material interfaces. This eliminates galvanic corrosion and material incompatibility issues while maintaining secure mechanical attachment. The pins are resiliently mounted in recesses of the same material family, ensuring chemical and physical compatibility.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The spring-loaded pins act as intermediary elements between the conducting elements and the carrier. These pins provide a flexible mechanical connection that maintains precise positioning while allowing for thermal expansion and contraction. The pins are resiliently mounted to provide continuous contact pressure, ensuring stable electrical connection without rigid fixation.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If contact elements use simple mounting structures, then assembly is easier, but reliability of connection decreases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmounting structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring-loaded pins are pre-loaded with elastic force to provide continuous contact pressure between the conducting elements and the carrier. This beforehand cushioning ensures reliable electrical connection by maintaining constant mechanical pressure, compensating for manufacturing tolerances and thermal expansion. The resilient mounting absorbs stress and prevents loose connections without requiring complex adjustment mechanisms.

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 design simplifies assembly, enhances current conduction, and improves the switch's reliability and performance in high voltage applications by reducing material interactions and electrical field exposure, while maintaining high dielectric withstand levels and fast switching times.

Implementation Method 1

with the positions of the conducting elements being such that in a first mutual position of the contact elements the conducting elements form at least one conducting path between the first terminal and the second terminal... with the conducting elements mounted onto the carrier part are locked into their operating position by one or more spring-loaded pins

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2876657B1Contact elements for medium to high voltage switches
Publication Date: 2021.07.07 HITACHI ENERGY SWITZERLAND AG
  • EP2876657B1 patent drawingFigure 1
  • EP2876657B1 patent drawingFigure 2
  • EP2876657B1 patent drawingFigure 3A~4C

AI summary

A medium or high voltage switch has a first set of contact elements (13a, 13b, 13c) and a second set of contact elements (14a, 14b, 14c). Each contact element consists of an insulating carrier (15) carrying conducting elements (16). In the closed state of the switch, the conducting elements (16) align to form one or more current paths between terminals (8, 9) of the switch along an axial direction (A). For opening the switch, the contact elements are mutually displaced by means of two drives (18, 19) along a direction (D) perpendicular to the axial direction (A) with the conducting elements (16) mounted onto the contact elements by means of springloaded pins (161,162).