Sequential-Break Excitation Fuse for High-Fault Current Interruption
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Solution Overview
Problem
Existing fuses, particularly those used in electric vehicles, struggle to effectively break large fault currents and provide quick protection against overloads and short circuits, especially in scenarios like incomplete short circuits where the current is not sufficient to fuse the fuse in time.
Innovation Solution
The excitation fuse with a conductor and a fusant being sequentially broken by a mechanical force, which includes a housing with a conductor and a fusant in parallel, an excitation device, and a breaking device that receives an external signal to sequentially break the conductor and the fusant, improving arc extinguishing capacity and breaking speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fuse with low-current specification is selected to protect against small overloads, then sensitivity to low-level faults is improved, but the fuse cannot withstand large fault currents or short-term overload currents
Solution Approach 1:
The fuse element is divided into two separate components: a conductor for carrying normal and overload currents, and a fusant (fuse element) that only carries current when the conductor is broken. This segmentation allows each component to be optimized for its specific function - the conductor can be sized for normal operation while the fusant provides arc extinguishing capability.
Solution Approach 2:
The conductor acts as an intermediary component between the power source and the fusant. During normal operation and even during faults, the conductor carries the current and protects the fusant from excessive heating. Only when the conductor breaks does the fusant become active to extinguish the arc, providing a staged protection mechanism.
2Strength
If a fuse with high-current specification is selected to withstand large fault currents, then breaking capacity is improved, but the fuse cannot respond quickly to small overloads or incomplete short circuits
Solution Approach 1:
By separating the current-carrying function (conductor) from the arc-ex extinguishing function (fusant), the system can use a thin, fast-responding conductor for sensitivity while maintaining a robust fusant design for high breaking capacity. The conductor's small cross-section enables rapid heating and breaking response to even small overloads.
Solution Approach 2:
The conductor is designed with excessive safety margin - it can withstand the full rated current plus overload currents without breaking. This allows the fusant to remain inactive during normal operation and only activate when truly needed (when conductor breaks), ensuring fast response only when required while maintaining high breaking capacity.
3Reliability
If a hot-melting fuse is used for circuit protection, then automatic protection is provided, but the fuse cannot be triggered by external signals or communicate with control systems
Solution Approach 1:
The fuse assembly serves multiple functions: the conductor provides both normal current carrying and fault detection, the fusant provides arc extinguishing, and the breaking device provides mechanical breaking action. This multi-functional design allows the same structure to provide both automatic thermal protection and external signal-triggered protection, enhancing versatility while maintaining reliability.
4Speed
If air is used to cool and extinguish the arc in a fast-breaking fuse, then breaking speed is improved, but the arc extinguishing ability is limited and breaking capacity is affected by environmental conditions
Solution Approach 1:
The fusant acts as an intermediary substance between the arc and the environment. When the conductor breaks and an arc forms, the fusant melts and vaporizes to create a metal vapor barrier that interrupts and extinguishes the arc. This mediates the arc extinguishing process, making it less dependent on external environmental factors like air pressure, temperature, and humidity.
Solution Approach 2:
The fusant utilizes phase transitions (melting and vaporization) to extinguish the arc. When heated by the arc, the fusant transitions from solid to liquid and then to vapor, creating a metal vapor that effectively interrupts the arc. This phase change mechanism provides reliable arc extinguishing that is independent of environmental conditions, unlike air-cooled arcs whose behavior varies with air pressure, temperature, and humidity.
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 solution enhances the breaking capacity and reliability of disconnecting the fuse under fault conditions, effectively extinguishing arcs and ensuring timely circuit disconnection, even under high fault currents.
Implementation Method 1
an excitation device and a breaking device are mounted in the cavity at one side of the conductor; the excitation device may receive an external excitation signal to act to drive the breaking device to sequentially form at least one fracture on the conductor and the fusant respectively
Implementation Method 2
A closed arc extinguishing chamber filled with an arc extinguishing medium is provided on the housing; and a part or all of the fusant is located in the arc extinguishing medium
Implementation Method 3
When the main electrically conductive terminal of the fuse is disconnected for circuit protection, an instantaneous large current will flow through the fusant and fuse the fusant, thereby achieving the purpose of arc extinguishing
Data Source
Figure 1~2
Figure 3~4b
Figure 5~6
AI summary
The present disclosure provides an excitation fuse with a conductor and a fusant being sequentially broken, the excitation fuse comprising a housing and a cavity in the housing, wherein at least one conductor is provided to be inserted in the housing and the cavity and has two ends connected with an external circuit; at least one fusant is provided in parallel on the conductor; an excitation device and a breaking device are mounted in the cavity at one side of the conductor; the excitation device may receive an external excitation signal to act to drive the breaking device to sequentially form at least one fracture on the conductor and the fusant respectively; and at least one fracture on the conductor is connected in parallel with the fusant. The fuse of the present disclosure can sequentially delay to break the conductor and the fusant, broadening the range of the breaking current, and improving the breaking capacity and arc extinguishing capacity.