Magnetic Yoke Fixed Contact Arc Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional protective switching devices face issues with contact erosion, arc re-ignition, and damage due to high temperatures during short circuits, which affect their switching behavior and reliability, particularly when using snap-action switches.
Innovation Solution
A magnetic yoke and protective switching device design that integrates a one-piece magnet yoke with a coupling area, a fixed contact area with a free end, and an arcing chamber, which reduces the number of parts, assembly work, and manufacturing costs, while improving switching behavior by dampening contact rebounds and redirecting arcs away from the contact area to the arcing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional fixed contact design is used, then the structure is simple, but contact erosion and welding occur due to arc damage
Solution Approach 1:
The patent extracts the arc away from the fixed contact by providing a dedicated arcing chamber with a free end of the fixed contact area that extends into the chamber. This allows the arc to form and burn in the chamber rather than directly on the contact surface, preventing contact erosion and welding while maintaining simple structure.
2Reliability
If multiple separate components are used for the magnetic yoke and fixed contact, then each component can be optimized, but the number of parts and assembly work increases
Solution Approach 1:
The patent merges the magnetic yoke and fixed contact into a single integrated component. The fixed contact area is formed as part of the magnetic yoke structure, eliminating the need for separate components and reducing assembly complexity while maintaining optimized performance for both magnetic function and contact function.
Solution Approach 2:
The magnetic yoke component performs multiple functions: it provides the magnetic circuit for the short-circuit release system and simultaneously serves as the fixed contact for the switching contact. This multi-functionality reduces the total number of components while achieving the desired reliability improvements.
3Stability of the object's composition
If the fixed contact area is rigidly mounted, then the structure is stable, but contact rebound causes damage during snap-action switching
Solution Approach 1:
The patent introduces dynamic flexibility to the fixed contact area by providing a free end that can move relative to the magnetic yoke body. This allows the fixed contact to absorb rebound forces during snap-action switching through controlled movement, reducing damage while maintaining overall structural stability.
4Reliability
If current continues to flow after arc commutation, then the circuit remains complete, but excessive heating and re-ignition occur
Solution Approach 1:
The patent extracts the arc from the contact area and directs it into a dedicated arcing chamber. The free end of the fixed contact area extends into this chamber, allowing the arc to burn away from the main contact region. This prevents excessive heating and re-ignition by isolating the arc from the contact area after commutation.
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 design enhances switching behavior, reduces contact damage, and minimizes thermal stress on the fixed contact area by interrupting current flow after arc commutation, thereby preventing re-ignition and excessive heating, leading to improved reliability and cost-effectiveness.
Implementation Method 1
a magnetic yoke which is arranged adjacent to the coil of the short-circuit release system and serves to increase the magnetic effect of the coil on the release mechanism
Implementation Method 2
an arc forms between the movable contact and the fixed contact when the current-carrying switching contact opens
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2D
AI summary
The protective switching device (1) according to the invention, which is designed in particular as a circuit breaker, has an input terminal (3-1) and an output terminal (3-2) which are designed for connecting the protective switching device (1) to an electrical conductor. Furthermore, the protective switching device (1) has a switching contact which in turn has a fixed contact (4) and a movable contact (5) relative to it, designed such that an arc (7) forms between the movable contact (5) and the fixed contact (4) when the current-carrying switching contact opens. The protective switching device (1) also has a short-circuit release system which in turn has a coil (8) and a release element (9) mounted to move relative to it, and is designed to act on the movable contact (5) in the event of tripping in order to cause the switching contact to open.The short-circuit release system comprises a magnetic yoke (15) formed in one piece and featuring a coupling area (20). Furthermore, the fixed contact (5) is formed by a fixed contact area (30) of the magnetic yoke (15), which is integrally connected to the coupling area (20) at its first end (31), and whose second end (32) is designed as a free end. The magnetic yoke (15) also includes an quenching chamber area (40), which is integrally connected to the coupling area (20) and forms a bypass current path. When an arc (7) occurs due to the opening of the switching contact, this bypass path is energized from the fixed contact area (30) to the quenching chamber area (40) after the arc (7) commutations.