Dual-Contact Fusible Disconnect Switch for DC Arc Containment

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Solution Overview

Problem

Conventional fusible switch disconnect devices struggle with electrical arcing issues when switching high energy DC circuitry, leading to rapid contact degradation and potential catastrophic failure, while also being larger and more expensive than desired for compact applications.

Innovation Solution

A compact fusible switch disconnect device with a retractable fuse module and dual switch contacts, featuring a rotary actuator and interlock mechanism, which safely contains arc energy and allows manual or automatic switching without tools, using a nonconductive housing and integrated tripping mechanism to manage arc energy and prevent contact wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fusible switch disconnect devices are used for high energy DC circuitry switching, then switching functionality is provided, but electrical arcing causes rapid contact degradation and potential catastrophic failure

Engineering Contradiction:
Improvecontact durabilityVSAvoidelectrical arcing
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The switch contact system is divided into multiple contacts arranged in series within the housing. This segmentation distributes the electrical arcing across multiple contact points rather than concentrating it on a single contact, reducing the degradation rate of each individual contact and improving overall reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A nonconductive housing serves as an intermediary structure that contains and isolates the electrical arcing between multiple switch contacts. The housing provides a controlled environment that prevents uncontrolled arcing while maintaining the switching functionality, thereby protecting the contacts from excessive degradation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If conventional fusible switch disconnect devices are designed to handle high energy DC circuitry, then switching capability is achieved, but device size increases and cost rises

Engineering Contradiction:
ImproveDC circuitry handling capabilityVSAvoiddevice size
Core Design Contradiction:
PowerVSVolume of stationary object

Solution Approach 1:

Multiple switch contacts are integrated within a single compact housing structure, combining the functionality of handling high energy DC circuitry with a space-efficient design. The merged structure achieves the required power handling capability without proportionally increasing device volume, as the contacts share common mounting and insulation structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The switch contacts are arranged in a multi-dimensional configuration within the housing, utilizing three-dimensional space efficiently. This spatial arrangement allows multiple contacts to be packed into a compact volume while maintaining adequate clearance for arc containment, thereby achieving high power capability without linear increases in device size.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 device effectively contains arc energy, reduces size and cost, and enhances safety by minimizing arcing risks during switching, enabling efficient and safe operation in high energy DC circuitry applications.

Implementation Method 1

when electrical current through the fuse exceeds a predetermined limit, the fusible elements melt and open one or more circuits through the fuse

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

The dual slide bar elements are each coupled to bias elements that store and release energy to affect switch opening and closing operations

Methodology Applied
Scientific EffectElastic energy storage: Elasticity

Implementation Method 3

A compact fusible switch disconnect device with a retractable fuse module and dual switch contacts, featuring a rotary actuator and interlock mechanism, which safely contains arc energy and allows manual or automatic switching without tools

Methodology Applied
Scientific EffectElectrical arcing: Electric Arc

Data Source

PatentEP3411892B1Fusible switch disconnect device for DC electrical power system
Publication Date: 2025.08.20 EATON INTELLIGENT POWER LTD
  • EP3411892B1 patent drawingFigure 1
  • EP3411892B1 patent drawingFigure 2
  • EP3411892B1 patent drawingFigure 3~4

AI summary

A fusible disconnect switch devices includes dual sets of switch contacts to connect or disconnect a current path through an overcurrent protection fuse with reduced arcing severity. Faster acting and longer contact path switch mechanisms are described providing satisfactory switching of DC circuits without excessive electrical arcing in a reduced physical package size.