Shearable Conductor Switch for High-Current Arc Interruption
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Solution Overview
Problem
Existing switches for high current applications require large conductors, making it difficult to break the current conduction path efficiently, and often result in bulky and costly switch arrangements due to the need for high forces and large pyrotechnic actuators.
Innovation Solution
A switch design featuring a conductor with shearable portions and insert conductors retained by temporary joints, where a moveable member actuated by a pyrotechnic or similar actuator displaces the insert conductors and shears the conductor, allowing for efficient breaking of the current path with smaller actuators and reduced forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large conductor is used to carry high current, then the current carrying capacity is improved, but the difficulty of breaking the conductor increases
Solution Approach 1:
The conductor is divided into multiple segments with reduced cross-sectional areas at specific locations. These segmented portions are easier to break while the main conductor body maintains high current carrying capacity. The segments act as predetermined weak points that facilitate conductor breaking without requiring the entire conductor to be thin.
Solution Approach 2:
The conductor has non-uniform cross-sectional area along its length, with local reductions at specific positions. These local quality changes create regions of lower mechanical strength that are easier to fracture, while the majority of the conductor maintains full current carrying capability. This allows the conductor to be both strong for high current and weak at specific points for easy breaking.
2Productivity
If high forces are used to break the conductor, then the conductor breaking effectiveness is improved, but the actuator size and cost increase
Solution Approach 1:
By segmenting the conductor into portions with reduced cross-sectional areas, the force required to break the conductor is significantly reduced. The segmented structure creates natural stress concentration points that require minimal force to fracture, eliminating the need for large, expensive actuators while maintaining effective conductor breaking.
Solution Approach 2:
The cross-sectional area parameter of the conductor is changed at specific locations to create weak points. By reducing the cross-sectional area at these locations, the mechanical strength is reduced accordingly, allowing the conductor to be broken with low forces. This parameter modification enables the use of small, inexpensive actuators while achieving effective conductor breaking.
3Ease of manufacture
If the conductor cross-sectional area is reduced to ease breaking, then the ease of breaking is improved, but the current carrying capacity decreases
Solution Approach 1:
The conductor is segmented such that only specific portions have reduced cross-sectional areas, while the main conductor body maintains full size for high current carrying capacity. The segmented structure provides easy breaking points without compromising the overall current carrying capability of the conductor system.
Solution Approach 2:
The conductor exhibits local quality variations along its length, with specific regions having reduced cross-sectional areas for easy breaking while the majority of the conductor maintains full current carrying capacity. This spatial differentiation of properties allows simultaneous optimization of both breaking ease and current carrying capacity.
4Speed
If a pyrotechnic actuator is used to break the conductor, then the rapid opening capability is improved, but the actuator size increases for high current applications
Solution Approach 1:
The segmented conductor structure enables rapid opening with minimal force, allowing the use of small pyrotechnic actuators. The segmentation creates inherent weak points that require very little energy to fracture, so even small pyrotechnic devices can achieve rapid conductor breaking without requiring large actuator sizes.
Solution Approach 2:
By modifying the cross-sectional area parameter at specific conductor locations, the energy required for conductor breaking is dramatically reduced. This allows small pyrotechnic actuators to provide sufficient energy for rapid opening, eliminating the need for large pyrotechnic devices while maintaining rapid response 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
This design enables quick and reliable opening of high current conduction paths with smaller, cheaper switches by maintaining mechanical stability and reducing arc severity, facilitating safer and more robust electrical arc interruption.
Implementation Method 1
the actuator is arranged to rapidly generate a gas volume expansion to move the moveable member in the first direction towards the switching region
Implementation Method 2
the moveable member is configured to at least partially displace the insert conductor from the hole with a first end portion of the moveable member and then shear the at least one shearable portion of the conductor with a respective second end portion of the moveable member
Data Source
AI summary
A switch includes: an actuator; a conductor having a length extending between two ends and a width extending between two sides, the conductor having a connection contact at either end and at least one switching region disposed between the connection contacts, each switching region extending between two sides of the conductor and including: a hole through the conductor, at least one shearable portion bounded by the hole and a nearest of the two sides of the conductor, and an insert conductor inserted into the hole and in electrical contact with the conductor, via the hole, such that a current conduction path is defined along the length of the conductor via the insert conductor and the at least one shearable portion of each switching region; and a moveable member aligned with the at least one switching region and arranged to move in a first direction.