Segmented Rotary Transformer Assembly Stress Reduction
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Solution Overview
Problem
Existing rotary transformers with segmented electrical assemblies face issues such as stress and damage to brittle active materials due to drilling for cable access, and their design is not optimized for lower power and frequency applications.
Innovation Solution
The development of segmented electrical assemblies with a constant circumferential cross-sectional area along the radius, using powdered iron as active material, and a U-shaped configuration that allows for easier assembly and reduced stress, suitable for lower power (≤25 kW) and frequency (50/60 Hz) applications, including a friction fit or fastener-based coupling for the rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hole is drilled through the active material to enable cable extension, then cable access is enabled, but stress and damage occur in the brittle active material
Solution Approach 1:
The access hole is formed in the mold during the manufacturing process before the active material is fully cured, allowing the hole to be created when the material is still pliable and less prone to damage. This preliminary action enables cable insertion without drilling through the hardened brittle material, thus maintaining structural integrity while achieving cable access.
2Ease of manufacture
If segmented electrical assemblies are used, then assembly flexibility is improved, but manufacturing complexity increases
Solution Approach 1:
The electrical assembly is divided into multiple segments that can be manufactured separately and then assembled together. Each segment is formed as a U-shaped structure with recesses that receive windings, allowing independent manufacturing and quality control. The segments are coupled using friction fit or fasteners, providing assembly flexibility while managing manufacturing complexity through modular design.
3Loss of energy
If the circumferential cross-sectional area increases with radius, then magnetic flux distribution is optimized, but material stress concentration occurs
Solution Approach 1:
The active material is configured with varying cross-sectional area along the radius, with each segment having a specific shape that optimizes magnetic flux distribution in its local region. The U-shaped segments with tapered legs create different cross-sectional areas at different radial positions, allowing optimized magnetic performance while distributing stress more evenly through the varied geometry rather than uniform thickness.
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 enhances the efficiency and reliability of rotary transformers by minimizing material stress, facilitating easier manufacturing, and enabling efficient power transmission in lower power and frequency applications, such as wind turbine energy transfer.
Implementation Method 1
Each segment of the electrical assembly is configured to have a substantially constant circumferential cross-sectional area along a radius of the electrical assembly, which minimizes stress in the active material
Implementation Method 2
The segments may be coupled together using a friction fit or fasteners
Implementation Method 3
Powdered iron may be used as the active material in the electrical assembly
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An electrical assembly includes a ring having at least two annular segments (112). Each annular segment includes a first portion (114) and a second portion (116). The second portion tapers from the first portion toward an end (128) of the second portion to define a circumferential cross-sectional area of the ring that is substantially constant along a radius of the electrical assembly. At least one winding is coupled about the ring.