Circuit Breaker Contact Assembly Segmentation for Electrodynamic Stability
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Solution Overview
Problem
Conventional circuit breakers face challenges in maintaining operational life and durability, particularly in withstanding electrodynamic repulsion forces during high current flow, which can lead to movement or falling off of moving runners during short circuits.
Innovation Solution
The contact arm assembly features a design with pivotally attached finger assemblies and a cage bracket configuration that includes parallel plates and extension plates forming a U-shape, providing a robust and rigid structure with advanced arc runners and locking features to minimize movement and enhance durability. This design includes a flexible conducting member and springs to assist in opening the circuit contacts during a short circuit event.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional circuit breaker contacts are used, then the structure is simple, but the moving runners may move or fall off during short circuit due to electrodynamic repulsion forces
Solution Approach 1:
The contact arm is divided into multiple finger assemblies (first, second, third finger assemblies) that are pivotally attached to parallel plates. Each finger assembly can independently withstand electrodynamic forces, preventing catastrophic failure and reducing the risk of moving runners falling off during short circuits.
Solution Approach 2:
The patent introduces a cage bracket structure with parallel plates arranged in a multi-dimensional configuration. This spatial arrangement provides additional structural support and constraint in multiple directions, effectively preventing movement of moving runners during high current conditions while maintaining a manageable overall structure.
2Strength
If the contact arm assembly uses a robust cage bracket structure, then the electrodynamic repulsion forces are withstood, but the manufacturing complexity increases
Solution Approach 1:
The cage bracket is segmented into multiple parallel plates (first, second, third parallel plates) with defined spacing. This segmentation allows for modular manufacturing and assembly, reducing overall complexity while maintaining the strength needed to withstand electrodynamic repulsion forces during high current flow.
Solution Approach 2:
The patent employs extension plates that extend beyond the basic structural requirements. These extension plates provide additional support and attachment points for the finger assemblies, enhancing the overall strength and stability of the contact arm assembly to handle extreme electrodynamic forces.
3Stability of the object's composition
If the arc runner is locked against the body in multiple locations, then the movement is prevented, but the manufacturing precision requirements increase
Solution Approach 1:
The arc runner is locked against the finger assembly body at specific critical locations (at least two locations) rather than uniformly along its entire length. This localized locking approach provides sufficient positional stability to prevent movement during operation while reducing the overall manufacturing precision requirements compared to a fully constrained design.
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 improved contact arm assembly significantly increases operational life and durability by providing a secure coupling between moving arc runners and the finger body, effectively withstanding large electrodynamic repulsion forces and reducing wear, thus preventing movement during high current conditions.
Implementation Method 1
the contacts must be locked closed at the current withstand rating and be able to withstand the large electrodynamic repulsion forces generated by the current flow
Implementation Method 2
This design includes a flexible conducting member and springs to assist in opening the circuit contacts during a short circuit event
Data Source
Figure 1A~1F
Figure 2A~3B
Figure 2C~3D
AI summary
A contact arm assembly including a plurality of substantially parallel plates (230) having a space between each of the plurality of substantially parallel plates and a plurality of finger assemblies (201-204), at least one of the plurality of finger assemblies being pivotally attached to the plurality of substantially parallel plates and being located in the space between each of the plurality of substantially parallel plates, each of the plurality of finger assemblies having a body and an arc runner, the arc runner being locked against the body in at least two locations.