Fuse Link Centering and Sealing via Segmented Taps
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Solution Overview
Problem
Existing fuse links for medium- or high-voltage systems face challenges in ensuring precise centering of the star-core relative to the external end caps and the spring-type striker pin, requiring additional labor-intensive welding and lacking effective sealing against external substances.
Innovation Solution
The fuse link design incorporates additional taps on the star-core end caps for precise centering, uses disc springs to attach the striker pin, and employs multiple seals to prevent external substance penetration, eliminating the need for welding and ensuring concentric positioning and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the star-core is supported unilaterally by a single tap on the star-core end cap, then the assembly process is simplified, but the central position of the star-core relative to the external end cap cannot be maintained
Solution Approach 1:
The single support point is segmented into multiple support points (first tap and second additional tap) on the star-core end cap. This segmentation provides both sides of the star-core with support, enabling precise centering while maintaining assembly simplicity.
2Strength
If the striker pin is fixed to the plug by welding, then the connection strength is improved, but additional welding operations are required making the process labour-intensive
Solution Approach 1:
The welding connection is replaced with a mechanical pressing connection. The striker pin is pressed into the plug with an interference fit, eliminating the need for welding operations while maintaining connection strength and simplifying the installation process.
3Reliability
If the external end cap is sealed using adhesive sealant, then the sealing effectiveness is improved, but the sealing compound may not sufficiently prevent oil penetration at multiple contact interfaces
Solution Approach 1:
A flexible sealing ring is introduced at the contact interface between the external end cap and the porcelain housing. This flexible membrane provides reliable sealing across multiple sealing interfaces, preventing oil penetration more effectively than adhesive sealant alone.
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 achieves precise mechanical contact and sealing, preventing external substance ingress and reducing installation complexity by avoiding welding, while ensuring effective protection against short circuits and overloads.
Implementation Method 1
a spring-type striker pin, the striker pin being positioned along the axis of the fuse link between the first and the second external end caps
Implementation Method 2
The housing is filled with an arc-quenching medium
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention relates to a fuse link (1) used in alternate current medium- or high-voltage systems with a current frequency of 50Hz, comprising a spring-type striker pin (8), and designed for the protection of electrical devices against the consequences of short circuits and overloads. The fuse link (1) comprises a porcelain housing (2) with a star-core (3), external end caps (11) closed by plugs (10a, 10b), star-core end caps (5) with a ringshaped first tap (7) designed to ensure electric contact between the star-core end cap and the external end cap of the fuse link. The spring-type striker pin (8) is positioned along the axis of the star-core (1). Each of the end caps of the star-core (5) is provided with an additional second tap (7') that is designed to centre the star-core (3) relative to the axis of the fuse link and is located on the circumference of the end cap of the star-core (5) at an obtuse angle (α) relative to the tap (7). Both taps (7, 7') are provided with spring contacts (6) bent in the direction of the longitudinal axis of the fuse link. The spring-type striker pin is centred along the longitudinal axis of the fuse link using tongues (20a) of a disc spring (20), installed in one of the plugs (10b) closing the fuse link (1) on the side where the striker pin (8) is positioned.