Triggered Fuse Bottleneck Design for Adaptive Low-Voltage Protection
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Solution Overview
Problem
Conventional melting fuses lack the ability to adapt to varying short-circuit conditions in low-voltage applications, particularly in surge protection devices, as they either fail to disconnect during high currents or disconnect prematurely, and existing solutions are either costly or have limited design flexibility.
Innovation Solution
A triggerable melting fuse with a fusible conductor and a mechanical separating element, actuated by a bridge igniter or shape memory alloy, allowing controlled disconnection independent of current flow, and capable of adapting to changing impedance values, enabling targeted protection characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional melting fuses are used for overcurrent protection, then protection is provided against short-circuits, but the fuse cannot adapt to varying short-circuit conditions and either fails to disconnect during high currents or disconnects prematurely
Solution Approach 1:
The fuse incorporates a trigger device that enables dynamic control of the fusible conductor disconnection. Instead of relying solely on passive thermal-melting characteristics, the trigger device can actively initiate disconnection at predetermined breaking points based on detected malfunction or overload states, allowing the fuse to adapt its protection behavior to varying short-circuit conditions.
Solution Approach 2:
The fuse design incorporates multiple predetermined breaking points along the fusible conductor with different mechanical strengths. By triggering disconnection at specific breaking points through the trigger device, the effective melting integral and disconnection characteristics can be dynamically changed to match different short-circuit scenarios, enabling adaptation to varying protection requirements.
2Adaptability or versatility
If circuit breakers with triggering characteristics are used instead of fuses, then adaptability to varying conditions is improved, but cost increases significantly
Solution Approach 1:
The invention applies a fuse-based approach rather than a circuit breaker approach. Fuses are inherently cheaper, disposable protective devices. By incorporating a simple trigger device that can initiate disconnection at predetermined breaking points, the fuse achieves triggering capability similar to circuit breakers but at much lower cost, as the fusible conductor itself serves as the sacrificial element.
Solution Approach 2:
The fusible conductor is divided into multiple segments with predetermined breaking points having different mechanical strengths. This segmentation allows the trigger device to selectively initiate disconnection at specific points along the conductor, providing adaptable protection characteristics while maintaining the simplicity and low cost of a fuse-based solution rather than requiring a complex circuit breaker mechanism.
3Adaptability or versatility
If additional breaking points are introduced in the fusible conductor, then adaptability and design flexibility are improved, but device complexity increases
Solution Approach 1:
The fusible conductor is segmented into multiple sections with predetermined breaking points at different locations, each having different mechanical strengths. This segmentation provides design flexibility to select which breaking point will be triggered first based on the severity and type of malfunction, while the breaking points themselves are simply structural features of the conductor rather than separate components, minimizing added complexity.
Solution Approach 2:
The predetermined breaking points are pre-engineered into the fusible conductor during manufacturing with specific mechanical strengths. This preliminary action allows the trigger device to selectively initiate disconnection at different points depending on the protection scenario, providing adaptability without requiring complex real-time adjustments or additional active components during operation.
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 provides cost-effective, high-switching-capacity protection with a small design, allowing for precise control of disconnection times and currents, effectively addressing the limitations of conventional fuses in low-voltage applications.
Implementation Method 1
a pyrotechnic charge is detonated when the current which flows through the current conductor of the fuses and is detected by a current detection device exhibits an intensity which is greater than a pre-definable threshold value
Implementation Method 2
actuated by a bridge igniter or shape memory alloy
Implementation Method 3
an extinguishing medium is introduced into the housing
Data Source
AI summary
The invention relates to a triggered fuse for low-voltage applications for protecting devices that can be connected to a power supply system, in particular surge protection devices, consisting of at least one fusible conductor which is located between two contacts and is arranged in a housing, and also consisting of a trigger device for controlled disconnection of the fusible conductor in the event of malfunctions or overload states of the respective connected device, wherein an arc quenching medium is introduced into the housing. The at least one fusible conductor has a plurality of conventional electrical bottlenecks, which are designed for the rated load of the respective fuse. At least one further additional geometric bottleneck is provided, which is disconnectable by rupturing depending on the trigger unit when applied by tension.