Electric Fuse Arc Barriers for DC Circuit Protection

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Solution Overview

Problem

Existing electric fuses with knife-blade contacts face issues with electric arc formation when used in direct current circuits, leading to the risk of fire, especially at higher voltages, and require longer fuses that are costly and difficult to fit into standardized seats.

Innovation Solution

The electric fuse incorporates flexible, short-term thermally resistant barriers made of silicone, with a semi-circular profile and a diameter of 2-6 mm, positioned between knife-blade contacts and weak zones along the melting member to prevent arc progression, and additional barriers between weak zones, maintaining a specific distance from the contacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the length of the melting member and casing is increased to prevent electric arc formation, then arc suppression improves, but the fuse becomes more expensive and difficult to fit into standardized seats

Engineering Contradiction:
Improvearc suppression capabilityVSAvoidfuse length
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent introduces arc barriers as intermediary elements positioned between the knife-blade contacts and the melting member. These barriers act as mediators that intercept and suppress electric arcs before they can form or propagate, eliminating the need to increase fuse length for arc suppression purposes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The fuse is segmented into functional zones by introducing arc barriers at specific locations. The barriers divide the internal space into distinct regions: a first region between the contacts and barriers where arcs are suppressed, and a second region between the barriers and melting member. This segmentation allows arc suppression without requiring the entire fuse to be longer.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If the fuse design is modified to prevent electric arc in direct current circuits, then safety improves, but the device complexity increases

Engineering Contradiction:
Improvefire risk from electric arcVSAvoidfuse structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The arc barriers are positioned locally at critical locations where electric arcs are most likely to form - specifically between the knife-blade contacts and the melting member. This localized approach provides effective arc suppression only where needed, rather than requiring complex modifications throughout the entire fuse structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The arc barriers are made from inexpensive materials such as silicone rubber or thermoplastic elastomers. These barriers are simple, low-cost components that can be easily integrated into the fuse design without significantly increasing overall device complexity or cost.

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

The solution effectively suppresses electric arcs, reducing the risk of fire and allowing for a more compact fuse design suitable for direct current applications without increasing costs or compatibility issues.

Implementation Method 1

prevent a fuse with knife-blade contacts from formation of electric arc in the area between said knife-blade contacts

Methodology Applied
Scientific EffectElectric Arc: Electric Arc

Implementation Method 2

the interior of said casing is filled with a granulated non-flammable means i.e. a filler, in particular with a sand on the basis of silica, by which said melting member is surrounded

Methodology Applied
Scientific EffectSilica Sand Arc Suppression:

Data Source

PatentEP3210231B1Electric fuse
Publication Date: 2020.07.01 RAZVOJNI CENT ENEM NOVI MATERIALI D O O
  • EP3210231B1 patent drawingFigure 1~2

AI summary

An electric fuse is in particular suitable for protecting direct electric circuits (DC). At least in each of terminal portions (31, 32) of a melting member (3), namely between each knife-blade contact (210, 220) and each neighboring weak zone (30, 30', 30''), on each of dominant surface (33, 34) which are faced apart from each other, at least one barrier (51, 51', 51''; 52, 52', 52'') is placed, which consists of a flexible at least short-term thermally resistant material and is intended to prevent progression of electric arc.