Contactor Arc Control via Asymmetric Magnet Placement
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Solution Overview
Problem
Existing contactor assemblies face challenges in safely switching high electric currents without welding or excessive arcing damage, often being large, heavy, and expensive, with polarity sensitivity and reduced contact forces when using permanent magnets for arc control.
Innovation Solution
A contactor assembly with an arcuate-shaped housing and internal arc dissipation areas, where arcuate permanent magnets create a magnetic flux that directs electric arcs into dissipation areas, increasing the arc's travel distance and preventing damage, while being insensitive to current polarity and maintaining contact force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent magnets are placed in contactors for arc control, then arc control is improved, but the device becomes polarity sensitive and contact force is reduced
Solution Approach 1:
The patent employs asymmetric magnet placement where magnets are positioned only on the stationary contactor body, not on the moving contact assembly. This asymmetric configuration eliminates polarity sensitivity because the magnetic field geometry remains effective regardless of current direction, while the magnets are positioned to avoid interfering with the moving contact's magnetic field during operation
Solution Approach 2:
The patent applies magnetic arc control only in specific localized regions where arcs are most problematic, rather than using magnets throughout the entire contactor. The magnets are strategically positioned near the stationary contact to control arcs without affecting the moving contact's magnetic field during closing operation, thus maintaining contact force while providing arc control where needed
2Reliability
If larger contacts and arc dissipation members are used to withstand large current surges, then current handling capability is improved, but the device becomes larger, heavier and more expensive
Solution Approach 1:
The patent replaces mechanical arc control methods (which would require large physical barriers and heavy construction) with a magnetic field-based system using permanent magnets. This substitution allows the contactor to handle large current surges and control arcs through electromagnetic forces rather than relying solely on increased physical size and mass of contacts and dissipation members
Solution Approach 2:
The patent changes the magnetic field parameters by introducing permanent magnets with specific strength and positioning, which fundamentally alters how arcs are controlled and how current is handled. This parameter change enables the contactor to withstand large currents without requiring proportionally larger physical dimensions, thereby reducing weight while maintaining reliability
3Reliability
If permanent magnets are positioned to control arcs, then arc dissipation is improved, but contact force is reduced due to magnetic field interaction
Solution Approach 1:
The asymmetric placement of magnets only on the stationary contactor body creates a magnetic field configuration that controls arcs from the stationary side without significantly interfering with the magnetic field generated by the moving contact during closing. This asymmetry allows arc dissipation to be improved while contact force is maintained
Solution Approach 2:
The patent applies magnetic arc control action partially, only where arcs are most likely to occur and cause damage (near the stationary contact), rather than applying magnetic fields throughout the entire contactor. This partial action provides sufficient arc dissipation while minimizing interference with the contact closing force
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 safe and efficient switching of high currents with reduced arcing damage, a compact design, and improved arc extinguishing performance, avoiding contact welding and maintaining contact force integrity.
Implementation Method 1
arcuate permanent magnets create a magnetic flux that directs electric arcs into dissipation areas
Implementation Method 2
magnetic flux that directs electric arcs into dissipation areas, increasing the arc's travel distance
Implementation Method 3
The magnets create magnetic flux or a magnetic field that extends across the current carrying contacts. The magnetic flux from the magnets directs electric arcs radiating from one or more of the current carrying contacts into the arc dissipation areas
Implementation Method 4
directs electric arcs radiating from one or more of the current carrying contacts into the arc dissipation areas, thereby increasing the effective distance that the electric arcs travel wherein the electric arcs are dissipated
Data Source
Figure 1
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Figure 3~4
AI summary
A contactor or switch assembly adapted for switching power to a circuit. The housing has internal walls that laterally extend within the interior compartment to define a protection chamber. Current carrying contacts are disposed in the protection chamber of the housing. The current carrying contacts include conductive bodies that protrude from the housing and are configured to close the circuit. Arc dissipation areas are provided in the protection chamber and are located proximate to the current carrying contacts. Magnets are provided proximate ends of the dissipation areas. The magnets create magnetic flux or a magnetic field that extends across the current carrying contacts. The magnetic flux directs electric arcs radiating from one or more of the current carrying contacts into the arc dissipation areas, thereby increasing the effective distance that the electric arcs travel wherein the electric arcs are dissipated in the dissipation areas.