Relay Contact Assembly Geometry for Short-Circuit Stability
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Solution Overview
Problem
Existing relays experience instability and potential explosions due to electro-dynamic repulsion forces causing staggered displacement and deformation of movable contacts under high short-circuit currents, leading to poor safety and performance.
Innovation Solution
The relay design includes a movable contact assembly with a V-shaped structure where the distance from the movable contact leading-out piece to the movable contact piece is varied, featuring a middle section with a larger distance and connection sections with smaller distances, reducing electro-dynamic repulsion forces and stabilizing contact pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a V-shaped structure is adopted for movable contact piece and movable contact leading-out piece to resist repulsion force under short-circuit current, then the electro-dynamic repulsion force is generated to maintain contact pressure, but the movable contact piece deforms upwards causing staggered displacement and contact instability
Solution Approach 1:
The movable contact leading-out piece is designed with non-uniform cross-sectional area, where the middle section has a larger cross-sectional area than the connection sections. This local quality variation creates different inertias along the structure, allowing the middle section to have greater resistance to deformation while maintaining the overall V-shaped configuration for electro-dynamic force generation.
2Reliability
If the movable contact piece maintains a fixed position to ensure stable contact, then contact resistance remains consistent, but the electro-dynamic repulsion force causes upward deformation of the movable contact piece leading to staggered displacement
Solution Approach 1:
The cross-sectional area parameter of the movable contact leading-out piece is changed along its length, with the middle section having a larger area than the connection sections. This parameter variation optimizes the distribution of mechanical properties, providing enhanced stiffness where needed while maintaining flexibility for contact pressure generation.
3Force
If the head of movable contact piece moves downward under compression, then force transmitted to push card increases, but the armature is pulled causing entire moving mechanism to move and contacts to bounce off resulting in explosion
Solution Approach 1:
The movable contact leading-out piece is segmented into distinct sections with different cross-sectional areas - the middle section with larger area and connection sections with smaller areas. This segmentation allows different parts to perform different functions: the middle section resists deformation while connection sections transmit force, preventing uncontrolled movement of the entire mechanism.
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 reduces upward deformation and stabilizes contact pressure, minimizing the risk of staggered displacement and explosions, enhancing safety and reliability during high short-circuit conditions.
Implementation Method 1
the movable contact piece is located between the static contact and the movable contact leading-out piece and is configured to generate an electro-dynamic repulsion force between the movable contact piece and the movable contact leading-out piece under a short-circuit current
Data Source
AI summary
A relay includes a static contact and a movable contact assembly including a movable contact leading-out piece, a movable contact piece connected to the movable contact leading-out piece and a movable contact disposed at a side of one end of the movable contact piece. The movable contact piece is between the static contact and the movable contact leading-out piece for generating an electro-dynamic repulsion force therebetween under a short-circuit current, to allow the movable contact to abut against the static contact. Between the movable contact and a connection position of the movable contact piece with the movable contact leading-out piece, a distance from at least part of the movable contact leading-out piece to the movable contact piece is greater than a distance from portions of the movable contact leading-out piece located at both sides of the at least part to the movable contact piece.