Low-Voltage Switch Pole Arc Chamber With Covered Terminal Plate
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Solution Overview
Problem
Existing low voltage switching devices suffer from uneven distribution of electric arcs among arc-breaking elements, leading to inefficient arc-quenching and potential damage to non-designated components due to high electrical and thermal stresses, exacerbated by higher energy arcs at modern operating voltages.
Innovation Solution
A switch pole design with an insulating casing containing a fixed and movable contact assembly, an arc chamber with parallel arc-breaking plates, and a terminal arc-breaking element with a cover and elongated portion to direct arcs efficiently through the arc chamber, enhancing arc-quenching and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional arc chambers with multiple arc-breaking elements are used, then arc-quenching capability is provided, but uneven distribution of electric arcs among arc-breaking elements occurs leading to inefficient arc-quenching
Solution Approach 1:
The arc chamber is segmented into multiple regions by dividing the arc-breaking element into several discrete arc-breaking plates arranged in sequence. This segmentation allows electric arcs to be systematically distributed across multiple controlled regions, ensuring each plate contributes to arc-quenching and preventing concentration of arcs in single areas, thereby improving arc-quenching efficiency while maintaining manageable structural complexity
Solution Approach 2:
A partition wall is introduced as an intermediary structure within the arc chamber, creating distinct arc-breaking regions separated by insulating barriers. This intermediary element guides and constrains arc paths between regions, ensuring uniform arc distribution across all arc-breaking plates while providing a clear structural framework that simplifies the overall arc chamber design
2Reliability
If arc-breaking elements are positioned to extinguish arcs, then arc-quenching action is provided, but electric arcs may bypass some arc-breaking regions or elements causing high electrical and thermal stresses in specific parts
Solution Approach 1:
Each arc-breaking plate is designed with specific local characteristics including varying dimensions, shapes, and positions tailored to its designated region within the arc chamber. This local customization ensures that each plate is optimally positioned to intercept and extinguish arcs in its specific zone, preventing arcs from bypassing any region and distributing electrical and thermal stresses uniformly across all components
Solution Approach 2:
The arc chamber is designed to create equipotential regions between adjacent arc-breaking plates through carefully controlled spacing and positioning. This equipotential arrangement ensures that electric arcs follow predictable paths between plates at similar potential levels, preventing arcs from concentrating in high-stress regions and ensuring uniform distribution of electrical and thermal loads across all arc-breaking elements
3Reliability
If arc-breaking elements are used to split electric arcs, then arc-quenching is achieved, but electric arcs may jump towards other conductive parts outside the arc-extinguishing region causing serious damages
Solution Approach 1:
The most critical arc-quenching function is extracted and concentrated in a dedicated terminal arc-breaking plate positioned at the exit region of the arc chamber. This terminal plate serves as the final barrier that definitively extinguishes arcs before they can escape to external conductive parts, isolating the arc-quenching function from other components and preventing arc damage to elements outside the arc-extinguishing region
Solution Approach 2:
The arc-breaking plates are constructed from composite materials combining high electrical conductivity for effective arc interception with high thermal resistance and mechanical strength to withstand repeated arc exposure. This composite material approach ensures that arcs are effectively quenched within the arc chamber while the materials themselves resist degradation from thermal and electrical stresses, preventing damage propagation to external components
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
Ensures uniform and efficient arc-quenching, reduces arc-related stresses, prolongs device lifetime, and prevents arcs from striking outside the arc-extinguishing region, while maintaining a simple and cost-effective manufacturing process.
Implementation Method 1
electric arcs may arise between the electric contacts under separation of the switch poles
Implementation Method 2
arc-breaking elements positioned near the electric contacts and designed to split possible electric arcs raising between the electric contacts
Implementation Method 3
enhancing arc-quenching and cooling
Data Source
AI summary
A switch pole for a low voltage switching device including an insulating casing defining an internal space with a contact region and an arc extinguishing region of said switch pole, a fixed contact assembly and a movable contact assembly positioned in said contact region and including, respectively, one or more fixed contacts and one or more movable contacts, which can be mutually coupled or uncoupled, and an arc chamber positioned in said arc extinguishing region and including a plurality of parallel arc-breaking plates and a terminal arc-breaking element, which includes a plate portion arranged in parallel to said arc-breaking plates and a cover of electrically insulating material coating, at least partially, a surface of said plate portion.