Arc Runner Hot Spots Enhance Circuit Breaker Arc Trapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing circuit breakers with arc plates face challenges in effectively attracting and trapping arcs, particularly at lower current ratings, due to reduced electromagnetic force and arc mobility, leading to restrikes and internal component erosion.
Innovation Solution
The design incorporates two arc runners with narrow portions acting as 'hot spots' to reduce the current path length and voltage, enhancing arc attraction and mobility within the arc plates, thereby reducing the likelihood of restrikes without the need for additional magnetic fields or gassing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If arc plates are used to attract arcs, then arc trapping capability is improved, but at lower current ratings the electromagnetic force is greatly reduced making arc attraction ineffective
Solution Approach 1:
The patent introduces arc runners with narrow portions that create localized hot spots at specific positions. These hot spots concentrate thermal energy locally to enhance arc mobility and attraction at the critical entry points to arc plates, compensating for the reduced electromagnetic force at lower current ratings without requiring additional magnetic fields or gassing materials throughout the entire structure.
Solution Approach 2:
The patent modifies the geometric parameters of the current path by introducing narrow portions in arc runners. This changes the local resistance and thermal characteristics of the current path, creating hot spots that enhance arc mobility. The parameter change transforms the uniform current path into a non-uniform one with strategically positioned constrictions that generate the necessary thermal conditions for effective arc attraction at lower currents.
2Power
If arc voltage is increased by arc plates, then current limiting is achieved, but arcs tend to breakdown again outside arc plates to reduce arc voltage causing restrikes
Solution Approach 1:
The patent positions arc runners and creates hot spots in advance at the entry points to arc plates. This preliminary thermal preparation ensures that when arcs are attracted, they encounter pre-heated pathways that facilitate smooth entry into arc plates. The preliminary action of heating the current path reduces the likelihood of arcs breaking down outside the arc plates by providing a thermally favorable path from the beginning.
Solution Approach 2:
The arc runners with narrow portions act as intermediaries between the contacts and arc plates. These intermediaries create controlled hot spots that mediate the arc's transition from the contact region to the arc plates. The intermediary structure provides a thermal bridge that helps maintain arc stability during the transition, reducing the tendency for restrikes by smoothing the voltage profile变化.
3Reliability
If gassing material and extra magnetic field are used to improve arc plate attraction, then arc trapping effectiveness is enhanced, but material cost and manufacturing cost increase
Solution Approach 1:
The patent enables the circuit breaker structure to serve itself by using its own current path to generate the necessary hot spots for arc attraction. The narrow portions in the arc runners utilize the operating current itself to create thermal conditions that enhance arc mobility and attraction. This self-service approach eliminates the need for external gassing materials or additional magnetic fields, thereby avoiding increased material and manufacturing costs while maintaining arc trapping effectiveness.
Solution Approach 2:
The patent extracts the essential function of arc attraction from external additives (gassing materials, permanent magnets) and implements it through the inherent electromagnetic and thermal characteristics of the circuit breaker's own current path. By taking out the dependency on expensive external components and using the existing current to create hot spots, the invention achieves arc plate attraction effectiveness without the associated cost increases.
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 configuration effectively traps arcs within the plates, reducing restrikes and arc erosion, while maintaining arc mobility and current limiting capabilities, thus improving the overall arc extinguishing performance and reducing costs.
Implementation Method 1
Arc plates are normally made of ferromagnetic materials, such as steel, and hence attract arcs with electromagnetic force.
Implementation Method 2
the two arc runners include narrow portions which operate as 'hot spots' in order to make the arc more mobile through the two arc runners and enable its quick travel downwards
Data Source
AI summary
An electronic circuit breaker comprises an arc interruption mechanism that would enhance arc attraction to arc plates and would reduce the possibilities of an arc escaping from the arc plates. The arc interruption mechanism includes an enhanced arc extinguishing chamber. The arc extinguishing chamber includes a plurality of arc plates having first and second sides. The circuit breaker further comprises a stationary contact plate that includes a first arc runner disposed near the first side of the plurality of arc plates. The circuit breaker further comprises a load terminal that includes a second arc runner disposed near the second side of the plurality of arc plates. As an arc is attracted by the plurality of arc plates and the arc enters the plurality of arc plates, a length of a current path associated with the arc is reduced through the first arc runner and the second arc runner by reducing a resistance of the current path for the arc or by reducing a voltage across the circuit breaker.