Axial Magnetic Field Coil for Vacuum Interrupter Arc Quenching
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Solution Overview
Problem
Conventional high voltage electrical switches face issues with vapor arc constriction and degradation at currents over 10 kiloamps, leading to failure in quenching the arc, particularly due to inadequate magnetic field geometry in contact assemblies.
Innovation Solution
The implementation of a contact assembly with an axial magnetic field (AMF) coil, comprising multiple helical sections connected to a contact disc and support, generates a diffuse arc mode, effectively extinguishing the vapor arc in high-current applications by maintaining a non-destructive arc behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic field geometry is used in contact assemblies, then the device structure is simple, but vapor arc constriction and degradation occur at currents over 10 kiloamps
Solution Approach 1:
The magnetic field coil is divided into multiple discrete sections or turns arranged in a specific geometry, allowing each segment to contribute to the overall axial magnetic field while maintaining manufacturing feasibility and enabling optimization of the field distribution pattern
Solution Approach 2:
The magnetic field geometry parameters (coil diameter, turn spacing, number of turns, wire gauge) are specifically optimized to generate the required axial magnetic field strength and distribution pattern that maintains diffuse arc mode at high currents over 10 kiloamps
2Reliability
If adequate magnetic field geometry is implemented to prevent vapor arc constriction, then arc quenching reliability improves, but the coil structure becomes more complex
Solution Approach 1:
The coil is configured in a helical or circular geometry rather than a straight linear arrangement, creating a concentrated axial magnetic field in the central region where the arc occurs, which is more effective for arc control while using standard winding techniques
Solution Approach 2:
The magnetic field coil serves multiple functions: generating the axial magnetic field for arc diffusion, providing structural support for the contact assembly, and potentially serving as a structural element that can be integrated into the overall contact assembly design to reduce other supporting 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
The solution effectively quenches high-current arcs over 10 kA, preventing localized degradation and ensuring reliable operation in high-voltage equipment like circuit breakers and switchgear by maintaining the vapor arc in a diffuse mode within the vacuum atmosphere.
Implementation Method 1
an axial magnetic field (AMF) coil, comprising multiple helical sections connected to a contact disc and support, generates a diffuse arc mode, effectively extinguishing the vapor arc
Data Source
AI summary
A contact assembly for use in a vacuum interrupter includes a contact disc of a first electrically conductive material, a coil, and a contact support. The coil is made from a second electrically conductive material and includes multiple helical sections that are oriented axially with respect to a common central axis. Each of the helical sections includes a proximal end and a distal end such that each of the helical sections is connected at the proximal end to a base made from the second electrically conductive material and is connected at the distal end to the contact disc. The contact support is centered axially within the coil and extends from the base to the contact disc.