Variable Thickness Yoke for Bus Connector Current Density
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Solution Overview
Problem
Current turnable joint mount (TJM) connectors for circuit breakers to power bus bars lack optimal current density distribution, fail to mitigate proximity and skin effects, and do not effectively manage thermal convection, leading to inefficiencies and potential electrical hazards.
Innovation Solution
The design incorporates a power connector with a fork-shaped head and a yoke having a transverse cross-section with varying length and width, optimized using multi-physics analytical tools and improved metal casting processes to enhance heat dissipation, mechanical strength, and reduce material usage while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solid square-shaped cross-section yoke is used in TJM connectors, then structural strength is provided, but current density distribution is not optimal and proximity effect and skin effect are not mitigated
Solution Approach 1:
The yoke cross-section is designed with non-uniform thickness distribution, where the thickness varies locally to optimize current density. The thickness is greatest at the center and decreases toward the edges, creating different local properties that simultaneously provide structural strength where needed and optimal current distribution where required, resolving the contradiction between mechanical strength and electrical performance
Solution Approach 2:
The invention changes the geometric parameters of the yoke cross-section from a uniform square shape to a variable thickness profile. By adjusting the thickness parameter as a function of position across the cross-section, the design achieves both adequate mechanical strength and optimal current density distribution, while also reducing proximity and skin effects through the non-uniform geometry
2Ease of manufacture
If traditional TJM connector design is used, then manufacturing simplicity is maintained, but heat dissipation and thermal convection are not optimized
Solution Approach 1:
The yoke cross-section transitions from a two-dimensional uniform square to a three-dimensional variable thickness profile. This dimensional complexity in the cross-sectional geometry enables enhanced thermal convection surfaces and optimized heat dissipation pathways while still being manufacturable through conventional processes, resolving the contradiction between manufacturing simplicity and thermal performance
3Loss of substance
If material is reduced in yoke design, then weight and material cost decrease, but structural integrity during installation and high-current interruption may be compromised
Solution Approach 1:
The variable thickness design concentrates material where structural strength is most needed (at the center of the cross-section) and reduces material where it is less critical (toward the edges). This local optimization maintains structural integrity during installation and high-current interruption while achieving overall material reduction and weight savings
Solution Approach 2:
The invention effectively creates a composite-like structure within a single material by varying the thickness distribution. The non-uniform geometry creates regions of different material density and structural contribution, optimizing the balance between material usage and structural performance without requiring multiple materials or complex manufacturing processes
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 reduces material requirements, increases convective heat transfer, minimizes proximity and skin effects, and maintains structural integrity, ensuring robustness during installation and high-current electrical interruptions.
Implementation Method 1
A yoke extends between and electrically connects the base to the fork-shaped head
Implementation Method 2
increases convective heat transfer
Implementation Method 3
minimizes proximity and skin effects
Implementation Method 4
minimizes proximity and skin effects
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
Power connectors (14) and switchgear assemblies (12) are presented herein. A power connector (114) is disclosed for electrically coupling a circuit breaker (10) to an electrically conductive bus bar. The connector includes a fork-shaped head (116) for electrically connecting to the circuit breaker, and a base (118) for electrically connecting to the bus bar. A yoke (120) extends between and connects the base to the fork-shaped head. The yoke has a transverse cross-section (136) with a length (LI) that is greater than a width (Wl). The length and/ or width of the transverse cross-section varies (LI', Wl') between respective ends of the transverse cross-section.