Circuit Breaker Contact Arm Internal Air Cooling
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Solution Overview
Problem
Circuit breakers with large electrical current capacities face high temperatures due to the large magnitude of electrical current, which existing designs struggle to manage effectively, leading to potential damage and inefficiencies.
Innovation Solution
The contact arm design incorporates a body with a hollow interior and fin openings that allow air to flow through, reducing temperature by facilitating heat dissipation through convection and conduction, while also providing a fastener opening for attachment to a terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the contact arm is made larger to accommodate high electrical currents, then the current carrying capacity is improved, but the temperature management becomes more difficult and the overall dimensions increase
Solution Approach 1:
The contact arm body is segmented into multiple sections with fins extending between the interior and exterior surfaces. These fins divide the heat dissipation function into multiple surfaces, increasing the total area for thermal exchange with the surrounding air, thereby improving temperature management while maintaining current carrying capacity
Solution Approach 2:
The patent introduces a third dimension for heat dissipation by extending fins radially outward from the contact arm body. This transforms the heat dissipation surface from a two-dimensional external surface to a three-dimensional structure with significantly increased surface area, enabling more effective thermal management without increasing the overall volume excessively
2Power
If the contact arm is made larger to accommodate high electrical currents, then the current carrying capacity is improved, but the overall dimensions of the contact arm increase
Solution Approach 1:
The contact arm is divided into a solid outer shell with internal hollow sections separated by fins. This segmentation allows the structure to maintain structural integrity for high current carrying while the hollow interior reduces the overall material volume and weight, achieving a compact design that can handle high currents without excessive dimensions
Solution Approach 2:
The fins serve multiple functions simultaneously: they act as structural supports dividing the hollow interior, provide thermal conduction paths from the interior to the exterior surface, and increase the external surface area for convection heat dissipation. This multi-functionality allows the same structure to achieve both mechanical strength and thermal management without adding extra components that would increase dimensions
3Temperature
If air cooling channels are added to reduce temperature, then the temperature management is improved, but the device complexity increases
Solution Approach 1:
The cooling function is merged into the structural design of the contact arm itself. The hollow interior and fins are not separate cooling components but are integrated into the load-bearing and current-carrying structure, eliminating the need for separate cooling systems and reducing overall device complexity while achieving effective temperature management
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 design effectively reduces the temperature of the contact arm, allowing for the safe handling of high electrical currents and reducing the overall dimensions of the contact arm, thereby enhancing performance and reliability.
Implementation Method 1
Air flows through the body opening, into the interior, and from the interior out through the fin opening to reduce a temperature of the contact arm
Implementation Method 2
a fin extending between the interior surface and the exterior surface
Data Source
AI summary
A contact arm for a circuit breaker includes a body extending along a body axis between a first end and a second end. The body includes an interior surface, an exterior surface, and a fin extending between the interior surface and the exterior surface. The body defines a fin opening adjacent the fin. The fin opening extends between the interior surface and the exterior surface. The interior surface defines a substantially hollow interior. A body opening is located at the first end in fluid communication with the interior. Air flows through the body opening, into the interior, and from the interior out through the fin opening to reduce a temperature of the contact arm.