Fusible Link with Asymmetric Constrictions and Thermal Preloading
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing overcurrent protection devices, such as fuses, have a sluggish switch-off characteristic due to high let-through energy values, making them less effective in responding to brief overcurrents and prone to false triggering under varying environmental conditions, particularly temperature and installation variations.
Innovation Solution
A fusible conductor with an elongate base body featuring rows of constrictions, where two central rows are closer together than the others, and an additional connection conductor for thermal preloading, allowing for a shift in the tripping characteristic to enhance sensitivity and adaptability to environmental influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional fusible conductors with uniform cross-section are used, then the fuse has simple structure and manufacturing, but the switch-off characteristic is sluggish and let-through energy values are high
Solution Approach 1:
The fusible conductor is divided into multiple sections with different cross-sectional areas along its length. The conductor comprises a first section with a first cross-sectional area and a second section with a second cross-sectional area, where the areas differ to create different melting characteristics in each section, enabling faster and more selective switch-off.
Solution Approach 2:
Different sections of the fusible conductor are given different local properties through varying cross-sectional areas. The first section has a larger cross-sectional area for higher current carrying capacity, while the second section has a smaller cross-sectional area for faster melting, creating localized quality differences that improve overall fuse performance.
2Reliability
If fusible conductors with reduced cross-section sections are used to improve switch-off characteristics, then the tripping becomes more sensitive, but the risk of false triggering under varying environmental conditions increases
Solution Approach 1:
The fuse system becomes dynamically adaptable by incorporating an adjustment mechanism that allows the melting characteristic to be modified based on environmental conditions. Thefusible conductor's effective melting point or tripping current can be adjusted dynamically to compensate for temperature variations and prevent false triggering while maintaining reliable protection.
3Ease of manufacture
If multiple rows of constrictions with equal spacing are used, then the manufacturing is simple, but the arc extinguishing efficiency is reduced
Solution Approach 1:
The rows of constrictions are arranged with asymmetric spacing rather than uniform intervals. At least one spacing between adjacent rows differs from the others, creating asymmetric patterns that improve arc extinguishing efficiency by optimizing the arc path and cooling characteristics while maintaining manufacturability.
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 enables earlier and more targeted tripping of the overcurrent protection device, reducing the risk of erroneous disconnection and allowing for flexible adaptation to different applications and environmental conditions, ensuring reliable operation across varying temperatures and currents.
Implementation Method 1
The fusible conductor, which has a reduced cross-section compared to the other conductors in the circuit, is heated by the current flowing through it and melts if the relevant nominal current of the fuse is significantly exceeded for a predetermined period of time.
Implementation Method 2
As the metal vapor of the evaporated fusible conductor is deposited on the surface of the quartz sand grains, the arc is cooled down again. As a result, the resistance inside the fuse link increases to such an extent that the arc is finally extinguished.
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
The fusible link (10) according to the invention for an overcurrent protection device (1) has an elongated base body extending in a longitudinal direction (L), the first end (14) of which has a first contact area for contacting a first contact element (4) of the overcurrent protection device (1), and the second end (15) of which has a second contact area for contacting a second contact element (5) of the overcurrent protection device (1). Between the first contact area and the second contact area, several rows of constrictions (11) are arranged, each row having a plurality of holes (16) which are arranged transversely to the longitudinal direction (L) of the fusible link (10).In a central region (12) of the fusible link (10), located midway between the first and second contact regions, two of the constriction rows (11-1, 11-2) are spaced closer together (a1) than the other constriction rows (11). Furthermore, in this central region (12), the fusible link (10) has at least one additional connecting conductor (17, 18) which is electrically connected to the fusible link. Using this additional connecting conductor (17, 18), the two constriction rows (11-1, 11-2) of the fusible link (10) located in the central region are selectively thermally pre-stressed by means of a predefined control current. In this way, the tripping characteristic of the fusible link (10), and thus the tripping characteristic of the overcurrent protection device (1), can be varied, allowing for more flexible adaptation to the respective operating conditions.