Relay Arc-Extinguishing Wall Structure for Variable Current
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Solution Overview
Problem
Existing relays face challenges in consistently extinguishing arcs across varying electric current levels due to the self-magnetic field generated by the fixed terminal, which affects the direction and force of the Lorentz force acting on the arc, making it difficult to secure effective arc extinguishing regardless of the current magnitude.
Innovation Solution
The relay design includes a movable contact piece, a fixed contact, a drive device, a magnet for arc extinguishing, and a wall portion with specifically arranged surfaces to apply Lorentz forces in different directions based on current magnitude, ensuring appropriate arc extinguishing by varying the distance between the arc and wall surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the distance between the starting point of the arc and the wall portion is small, then the arc can be pressed against the wall portion with sufficient force, but the space for stretching the arc becomes narrow making it difficult to sufficiently stretch the arc
Solution Approach 1:
The patent introduces a second extension direction (depth direction) in addition to the first extension direction (width direction) by providing a second wall surface that extends in the depth direction from the first wall surface. This dimensional extension allows the arc to be stretched in multiple directions simultaneously, resolving the contradiction between needing sufficient stretching space and maintaining pressing force.
2Device complexity
If a single wall portion is used for arc extinguishing, then the structure is simple, but it becomes difficult to appropriately extinguish arcs across different current magnitudes due to changing Lorentz force directions
Solution Approach 1:
The wall portion is segmented into multiple functional surfaces: a first wall surface for receiving arcs at lower current levels, and a second wall surface extending in the depth direction for receiving arcs at higher current levels. This segmentation allows each surface to be optimized for specific current ranges, improving adaptability while maintaining structural integration.
Solution Approach 2:
The patent makes the arc extinguishing system dynamic by allowing the effective wall surface to change based on current magnitude. At different current levels, different wall surfaces become active, enabling the system to adapt to varying Lorentz force directions and magnitudes without requiring manual adjustment.
3Ease of manufacture
If the direction of the wall portion is fixed, then the manufacturing is simple, but the arc stretching direction changes with current magnitude making consistent arc extinguishing difficult
Solution Approach 1:
The wall portion is designed with asymmetric geometry where the second wall surface extends in the depth direction at an angle relative to the first wall surface. This asymmetric configuration allows the structure to naturally guide arcs toward appropriate extinction zones based on current magnitude, maintaining manufacturing simplicity while achieving reliable performance across varying conditions.
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 allows for effective arc extinguishing across different electric current levels by adjusting the arc's stretching direction and force, ensuring reliable arc extinguishing regardless of current magnitude, with the ability to secure sufficient space for arc stretching and pressing force.
Implementation Method 1
a magnet for arc extinguishing arranged so as to apply a Lorentz force in a first extension direction to an arc generated between the movable contact and the fixed contact
Implementation Method 2
two magnets are arranged so as to mutually oppose each other in the width direction of a movable contact piece. The movable contact piece is arranged between the two magnets. When an arc is generated between the contact points, a Lorentz force acts on the arc due to the magnetic force of the magnets
Implementation Method 3
the behavior of an arc is affected by the self-magnetic field generated by an electric current flowing through the fixed terminal
Implementation Method 4
a Lorentz force F20 heading to the inner side in the longitudinal direction of the movable contact piece 100 is generated at the arc. Accordingly, a resultant force F30 of the Lorentz force F10 due to the magnetic force of the magnet 300 and the Lorentz force F20 due to the electric current flowing through the fixed terminal 200 acts on the arc
Data Source
AI summary
A relay includes a movable contact piece having a movable contact, a fixed contact, a drive device configured to move the movable contact piece, a magnet to apply a Lorentz force to an arc in a first extension direction, a fixed terminal having an intermediate portion to apply a Lorentz force to the arc in a second extension direction, and a wall portion. The wall portion includes first and second wall surfaces. The first wall surface is disposed to face an arc-extinguishing space, and is disposed opposite to the movable contact and the fixed contact in the first extension direction. The second wall surface is disposed to face the arc-extinguishing space and is disposed downstream in the second extension direction with respect to the first wall surface. A distance from the movable contact piece to the second wall surface differs from a distance to the first wall surface.