Electrical Contactor with Counter-Opposed Movable Arms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrical contactors face challenges in precisely controlling the opening and closing of contacts to prevent arcing and extend operational life, especially under short-circuit fault conditions, while also needing to reduce the size and material usage of contacts to minimize costs and prevent tack welding.
Innovation Solution
The design incorporates counter-opposed moveable arms with current-sharing configurations, magnetic forces to restrict contact bounce, and a lead-lag contact arrangement to distribute current and reduce erosion energy, along with laminated movable arms and a pivoting actuator mechanism to optimize contact closure timing with the AC waveform zero-crossing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the contactor uses larger contacts to handle higher currents, then the current-carrying capacity is improved, but the device size and material cost increase
Solution Approach 1:
The movable arm is divided into multiple segments (first movable arm and second movable arm) that can move independently. Each segment carries a portion of the total current, allowing the device to handle higher currents without proportionally increasing the size of each individual contact segment. The segmented structure distributes the electrical and mechanical load across multiple smaller components.
Solution Approach 2:
The patent transitions from a single-plane contact structure to a three-dimensional arrangement with movable arms extending in multiple directions. The first and second movable arms are positioned at different locations and can move independently, creating a spatial distribution of current paths that increases effective current-carrying capacity without proportionally increasing overall device volume.
2Duration of action of moving object
If the contacts are made larger to reduce erosion, then the operational life is improved, but the material usage and cost increase
Solution Approach 1:
The contact structure is segmented into multiple movable arms with multiple contacts. Each contact segment experiences reduced erosion because the total current is distributed across multiple contact points. This allows the use of smaller individual contact segments with less precious material (silver alloy) while maintaining or improving overall operational life through the distributed erosion resistance.
Solution Approach 2:
Different contact segments can be optimized with different material properties or geometries based on their specific erosion requirements. The first and second movable arms can have tailored contact surface areas, material compositions, or protective coatings suited to their local electrical and mechanical conditions, reducing overall material usage while maintaining durability.
3Quantity of substance
If the contacts are made smaller to reduce material cost, then the material usage is reduced, but the resistance to tack welding and erosion decreases
Solution Approach 1:
The movable arm is divided into multiple segments that share the total current. Each smaller contact segment carries a fraction of the total current, which reduces the heat generation and erosion at each individual contact point. This segmentation allows the use of smaller, more cost-effective contact segments while maintaining resistance to tack welding through the distributed current load and reduced thermal stress at each contact interface.
Solution Approach 2:
The patent introduces magnetic actuation mechanisms to replace or supplement purely mechanical contact closure. Magnetic forces can precisely control the timing and force of contact closure, ensuring optimal contact pressure and minimizing arcing and tack welding risks even with smaller contact segments. This mechanical-to-magnetic substitution enables reliable operation of smaller contacts.
4Volume of moving object
If the contactor is designed for compact size, then the ease of incorporation into meter housing is improved, but the heat dissipation capability worsens
Solution Approach 1:
The segmented movable arm structure creates multiple distributed current paths and contact points within the compact housing. This segmentation increases the surface area-to-volume ratio for heat dissipation, allowing efficient thermal management in a compact form factor. The distributed architecture prevents heat concentration at single points while maintaining small overall dimensions.
Solution Approach 2:
The patent utilizes three-dimensional spatial arrangement of movable arms and contacts to maximize heat dissipation surface area within a compact volume. By extending movable arms in multiple directions and positioning contacts at different spatial locations, the design creates efficient thermal pathways without increasing the footprint or overall housing size.
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
This solution effectively reduces arcing and heating, allowing for smaller, more cost-effective contacts with improved resistance to tack welding and contact bounce, thereby enhancing the operational life and reliability of the contactor.
Implementation Method 1
actuator means for providing motive force to the first and second electrically-conductive moveable arms in opposing directions
Implementation Method 2
ignores the possible magnetic forces which are generated by passing current through the arms, which could be harnessed to smooth the opening and closing of the contacts
Data Source
AI summary
An electrical contactor has a first terminal having a first fixed contact; a second terminal having a second fixed contact; a first electrically-conductive movable arm in electrical communication with the first terminal and having a first movable contact thereon; a second electrically-conductive movable arm in electrical communication with the second terminal and having a second movable contact thereon, counter-opposed to the first moveable arm; and an actuator for moving the first and second moveable arms in opposing directions. The first moveable contact and the second fixed contact form a primary contact set, and the second moveable contact and the first fixed contact form a secondary contact set, first and second moveable arms thereby forming a current-sharing arm pair between first and second terminals.