Relay Switch Parallel Conduction Paths for Lower Terminal Heat
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Solution Overview
Problem
Two-pole relays in electricity meters experience excessive heat rise at terminals due to high resistance, leading to failures in meeting temperature rise standards, particularly in micro-grid scenarios, with no cost-effective and safe disconnection options for residential solar systems.
Innovation Solution
A relay switch design featuring parallel electrical conduction pathways and thermally conductive couplings to distribute thermal loads, reducing heating effects and maintaining good short-circuit behavior, with optional secondary switching arm arrangements for improved thermal dissipation and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrical conduction pathway is used in the relay switch, then the structure is simple, but excessive heat rise occurs at the terminal junction point
Solution Approach 1:
The single electrical conduction pathway is segmented into two parallel pathways. The first pathway includes the switching arm arrangement between first and second terminals, while the second pathway includes an electrical conductor connected in parallel between the same terminals. This segmentation distributes the current load across multiple paths, reducing thermal concentration at any single junction point.
2Temperature
If parallel electrical conduction pathways are provided to reduce heat rise, then thermal load is distributed, but the device complexity increases
Solution Approach 1:
The parallel electrical conductor is merged with the existing switching arm arrangement to form an integrated relay switch structure. Both the switching arm pathway and the parallel conductor pathway are combined within the same device housing, sharing common terminals and actuation mechanisms. This merging approach distributes thermal load while maintaining a unified, compact structure rather than adding separate independent components.
3Temperature
If thicker contact arms are used to reduce heating, then thermal resistance decreases, but the device size and manufacturing cost increase
Solution Approach 1:
Instead of increasing the cross-section of the switching arm contact arms, the current pathway is segmented into parallel routes. The electrical conductor provides an alternative current path that bypasses the need to thicken the switching arm contact arms. This segmentation allows the use of thinner, more economical contact arms while still achieving acceptable thermal performance through the distributed current load.
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 effectively reduces thermal degradation and arcing damage, allowing the relay to meet thermal standards and enabling safe disconnection in micro-grid scenarios, such as residential solar systems, while maintaining compact and cost-effective design.
Implementation Method 1
On switching there is a significant local heat rise in the contact area, since the contact points account for in excess of 75% of the total resistance of the switch. This heat cannot be readily dissipated, which can lead to excessive heat rise at the busbars of the terminals.
Data Source
AI summary
A relay switch (42) for a relay (10) is provided which comprises a first terminal (14a, 14b), a second terminal (16a, 16b), and a switching arm arrangement (36) between the first and second terminals (14a, 14b, 16a, 16b) which forms a first electrical conduction pathway in a contact condition of the switching arm arrangement (36). An electrical conductor (49) is also arranged between the first and second terminals (14a, 14b, 16a, 16b) which forms a second electrical conduction pathway in the contact condition in parallel to the first electrical conduction pathway.