Bar Conductors with Tangential Voids for Electric Machines
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Solution Overview
Problem
Conventional bar conductors for electric machines experience high eddy current and proximity effects due to their rectangular shape, leading to increased resistance and reduced efficiency during operation.
Innovation Solution
The development of bar conductors with tangential depressions that create voids within a rectangular envelope, increasing the surface area and reducing eddy currents and proximity effects by forming air pockets or using fillers in these voids, thereby improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional rectangular bar conductors are used, then the manufacturing process is simple, but eddy current and proximity effects increase leading to higher resistance
Solution Approach 1:
The bar conductor is segmented by forming tangential depressions that divide the solid core into multiple regions separated by voids. This segmentation interrupts eddy current paths and reduces proximity effects between adjacent conductor regions, thereby reducing copper losses while maintaining manufacturing feasibility through processes like machining or molding.
Solution Approach 2:
The bar conductor incorporates a porous structure with tangential voids formed by depressions in the solid core. These voids act as air pockets that break eddy current loops and reduce electromagnetic coupling between adjacent conductors, decreasing energy losses without significantly complicating the manufacturing process.
2Loss of energy
If tangential depressions are formed to create voids, then eddy currents and proximity effects are reduced, but the surface area increases
Solution Approach 1:
The solution addresses the surface area increase by transitioning to a three-dimensional configuration with tangential voids rather than adding surface features in two dimensions. The voids extend into the conductor body, reducing eddy currents through volumetric separation rather than surface modification, thus minimizing the impact on surface area.
3Loss of energy
If the surface area of the solid core is increased beyond the rectangular envelope, then eddy current paths are interrupted, but the conductor complexity increases
Solution Approach 1:
The conductor is segmented into regions separated by tangential voids, creating a modular structure that interrupts eddy current paths. This segmentation achieves energy loss reduction through a systematic pattern of voids rather than complex irregular shapes, maintaining manufacturing simplicity while effectively reducing copper losses.
Solution Approach 2:
Instead of modifying the entire conductor surface uniformly, the solution applies local modifications in the form of tangential depressions at specific locations. These localized voids are positioned to effectively interrupt eddy current paths and reduce proximity effects without requiring complex overall conductor geometry.
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 modified bar conductors with tangential depressions or fillers in voids reduce copper losses, enhancing the operating efficiency of electric machines by minimizing resistance and electromagnetic field interactions.
Implementation Method 1
Conventional bar conductors for electric machines experience high eddy current and proximity effects due to their rectangular shape
Implementation Method 2
Conventional bar conductors for electric machines experience high eddy current and proximity effects due to their rectangular shape
Data Source
AI summary
A conductor is provided for an electric machine having an axis, a radial direction extending outward from the axis, and a tangential direction perpendicular to the radial direction. The conductor includes a solid core, having radial faces substantially perpendicular to the radial direction of the electric machine and tangential faces substantially perpendicular to the tangential direction of the electric machine. At least one tangential depression is formed on at least one of the tangential faces. The tangential depression creates a tangential void within a rectangular envelope defined by the solid core. Therefore, the surface area of the solid core is greater than the surface area of the rectangular envelope.