Switch Device Suction Bar Arc Extension
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Solution Overview
Problem
Switch devices with permanent magnets face reliability issues when reversing current direction, as the magnetic field's direction becomes unpredictable, leading to reduced interruption reliability and increased size due to the need for larger magnets and additional components like magnetic yokes to manage arc extension.
Innovation Solution
A switch device with a fixed and movable contact, an opening/closing mechanism, and a long-sized magnetic suction bar that integrates with the magnet's pole surface, allowing the arc to be driven along the suction bar's side surface, maintaining reliability regardless of current direction and reducing component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanent magnet is used to generate a magnetic field for arc extension, then the arc can be extended to enhance interruption capability, but the magnetic field direction becomes unpredictable when current direction is reversed, deteriorating interruption reliability
Solution Approach 1:
A magnetic yoke is introduced as an intermediary component to guide and control the magnetic field lines generated by the permanent magnet. The magnetic yoke ensures that the magnetic field consistently acts in the intended direction regardless of current reversal, thereby maintaining reliable arc extension and interruption capability across different current directions.
Solution Approach 2:
The magnetic circuit is designed with asymmetric structure where the magnetic yoke provides a preferred path for magnetic flux. This asymmetric magnetic circuit configuration ensures that the magnetic field direction remains consistent even when the current direction reverses, as the magnetic yoke guides the flux along its structured path rather than allowing random field distribution.
2Reliability
If the magnetic pole surface of the permanent magnet is made larger to ensure uniform magnetic field coverage, then the Lorentz force can act uniformly on the arc, but the device size and cost increase
Solution Approach 1:
The magnetic yoke serves as a flux concentrating intermediary that channels the magnetic field lines from a smaller magnet surface to the arc region. This allows a compact magnet to generate sufficient and uniform magnetic field coverage over the arc area, eliminating the need for a large magnet surface while maintaining reliable Lorentz force generation.
Solution Approach 2:
The magnetic yoke is strategically positioned and shaped to concentrate magnetic flux precisely where needed - at the arc region. This local concentration of magnetic field strength ensures uniform Lorentz force action on the arc without requiring the entire magnet surface to be large, thus reducing overall magnet size while maintaining arc extension reliability.
3Area of stationary object
If a magnetic yoke is added to guide the magnetic field, then the magnetic field coverage can be improved, but the device complexity and size increase
Solution Approach 1:
The magnetic yoke is designed to perform multiple functions simultaneously: it guides the magnetic field lines, provides structural support for the permanent magnet, and serves as part of the magnetic circuit closure. This multi-functionality allows improved magnetic field coverage without adding excessive complexity, as the yoke integrates several roles into a single component.
Solution Approach 2:
The magnetic yoke structure is merged with the housing or other structural elements of the switch device where possible, reducing the need for separate components. By combining the magnetic guiding function with existing structural elements, the device complexity is minimized while still achieving adequate magnetic field coverage.
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 enables efficient arc extension and cooling, maintaining high interruption reliability at a lower cost and smaller size, even with opposite current polarity, by guiding the magnetic field effectively and reducing wear on contact points.
Implementation Method 1
a magnet (4) which generates a magnetic field
Implementation Method 2
a line of magnetic force of a permanent magnet is made to interlink with the arc and a Lorentz force is made to act on the arc
Data Source
Figure 1
Figure 2(I)~2(V)
Figure 3~4
AI summary
A switch device includes a long-sized magnetic body (3) which comes into contact with the magnetic pole surface of a magnet (4) at one end portion and is extended between the magnet (4) and at least either one of a fixed contact (1) and a movable contact (2). Either one of both contacts (1) and (2) is integrally molded with the magnetic body (3) with magnetic material to constitute a suction bar integrated contact (10).