Vacuum Interrupter Electrode Undulations for Low Contact Resistance
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Solution Overview
Problem
Vacuum interrupters face challenges in maintaining low surge resistance and contact resistance characteristics due to adhesive wear caused by repeated separation and connection of electrodes, leading to increased contact resistance values.
Innovation Solution
The implementation of an undulating structure on the electrode opposed surfaces, featuring projections and depressions, provides a regular concavo-convex shape that enhances adhesive wear resistance while maintaining low surge resistance and contact resistance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode opposed surfaces are made smooth and soft to increase contact area, then contact resistance characteristics are improved, but adhesive wear increases due to slight slipping during repeated separation and connection
Solution Approach 1:
The electrode opposed surfaces are designed with local undulating structures (projections and depressions) rather than being uniformly smooth. This creates different local zones: the projections provide rigid contact points that resist wear, while the depressions accommodate material deformation and maintain contact stability. This local differentiation resolves the contradiction between smooth surfaces for low contact resistance and wear resistance.
Solution Approach 2:
The undulating structure introduces curved surfaces (projections and depressions) instead of flat surfaces. The curved geometry of the projections provides point contacts that concentrate stress and resist adhesive wear, while the overall concavo-convex shape maintains sufficient contact area for low contact resistance. This curvature-based design resolves the contradiction between smooth flat surfaces and wear-resistant surfaces.
2Loss of substance
If the electrode opposed surfaces are made rigid to resist adhesive wear, then wear resistance is improved, but contact area decreases leading to increased contact resistance
Solution Approach 1:
The electrode surfaces feature localized rigid projections for wear resistance combined with softer depression zones that deform to maintain contact. This local quality differentiation allows the rigid projections to resist wear while the overall structure maintains sufficient contact area through the compliant depression regions, resolving the contradiction between rigidity and contact area.
Solution Approach 2:
The design transitions from a two-dimensional flat surface to a three-dimensional undulating surface with projections and depressions. This dimensional change allows the surface to maintain volume (and thus wear resistance) while creating multiple contact points that collectively provide sufficient contact area. The third dimension resolves the contradiction between rigid wear-resistant surfaces and adequate contact area.
3Reliability
If smooth electrode surfaces are used to maintain low contact resistance, then contact area is maximized, but irregular projections and depressions form due to adhesive wear over time
Solution Approach 1:
The undulating structure (projections and depressions) is pre-formed on the electrode surfaces before operation. This preliminary action anticipates the adhesive wear that would normally create irregularities, and provides a controlled, uniform undulating pattern that resists further wear-induced irregularities. The pre-formed structure maintains surface uniformity while providing wear resistance.
Solution Approach 2:
The electrode surfaces are designed with intentional local undulations (projections and depressions) rather than being uniformly smooth. This local quality differentiation creates a stable, repeating pattern that resists adhesive wear by distributing stress across multiple contact points, preventing the formation of random irregularities while maintaining sufficient contact area for low contact resistance.
Data Source
AI summary
According to one embodiment, a Vacuum interrupter includes a pair of electrodes provided such that their electrode opposed surfaces face each other, and an undulating structure provided in at least one of the electrode opposed surfaces. The undulating structure includes one or more projections which project from the electrode opposed surface, and depressions provided so as to be adjacent to the projections, respectively. The projections and the depressions are alternately provided in a direction crossing the electrode opposed surface. In a conducting state in which the electrodes are in contact with each other, the projections are in contact with the opposite electrode opposed surface.