Multi-Plane Fusible Element Layout for Higher Surge I2t
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Solution Overview
Problem
Existing fuses face limitations in withstanding high surge currents due to their limited size and heat transfer capabilities, which restrict their ability to handle high I2t values in circuit protection applications, especially in inductive and capacitive loads.
Innovation Solution
A multi-plane serpentine fusible element design that extends along multiple planes, providing a longer length and increased resistance capability, combined with a silicone filler for enhanced arc quenching and robust termination, allowing for higher I2t values and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a traditional spiral wound fuse element is used, then the fuse can provide some heat absorption capability, but the overall length of the element is limited due to space constraints of the fuse housing
Solution Approach 1:
The fusible element transitions from a planar spiral wound configuration to a three-dimensional multi-plane serpentine configuration. This allows the element to extend in multiple spatial dimensions (first plane, second plane, and third plane), effectively increasing the total length of the fusible element without proportionally increasing the fuse housing volume. The serpentine pattern folded across multiple planes maximizes the use of available three-dimensional space within the housing.
2Reliability
If the fusible element length is increased to withstand higher surge currents, then the I2t capability improves, but the device complexity increases
Solution Approach 1:
The fusible element is divided into multiple straight segments connected in series, with each segment extending along a different plane. This segmentation allows the element to achieve increased total length and higher I2t capability while maintaining a structured, modular configuration. The segmented design also facilitates manufacturing and assembly, as the element can be formed by folding or bending a continuous conductor into the multi-plane serpentine pattern.
3Power
If a larger diameter fuse wire is used to withstand higher currents, then the current rating increases, but the heat transfer capability between the wire and core is limited
Solution Approach 1:
Instead of increasing wire diameter to handle higher currents, the invention increases the length of the fusible element by extending it across multiple planes. This three-dimensional configuration provides greater surface area for heat transfer to the ceramic core while maintaining a practical wire diameter. The extended path length allows more time and surface area for heat dissipation to the heat sink, improving thermal management capability.
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 multi-plane serpentine fusible element design increases the length of the fusible element, enhances resistance, and improves reliability, enabling higher I2t values while maintaining robust termination and ease of assembly, thus effectively addressing the limitations of existing fuses.
Implementation Method 1
When a circuit overload is encountered, the passage of the excess current through the fuse element causes it to generate heat and thereby elevate the temperature of the fuse wire
Implementation Method 2
The fibers that make up the core is typically a ceramic material that is devoid of any material that could become conductive when the fuse is blown. The wound wire may include a plurality of wire strands configured to provide increased heat absorption indicative of, for example, a slow-blow or time-delayed fuse. When a circuit overload is encountered, the passage of the excess current through the fuse element causes it to generate heat and thereby elevate the temperature of the fuse wire. In other words, the core acts as a heat sink to draw this heat away from the fuse wire, thereby lowering the temperature of the fuse wire
Data Source
AI summary
Disclosed are various protection devices and associated methods. In some embodiments, a protection device may include a substrate and a fusible element coupled to the substrate, wherein the fusible element may include a first end opposite a second end, and wherein the first and second ends wrap around the substrate. The fusible element may further include a central section comprising a plurality of segments connected end-to-end in a continuous arrangement between the first and second ends, wherein a first set of segments of the plurality of segments extends along a first plane, and wherein a second set of segments of the plurality of segments extends along a second plane, different than the first plane.