Stator Connecting Section Insulation for Corner Breakdown Prevention
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Solution Overview
Problem
Existing stator designs face challenges in achieving efficient electrical insulation at corner sections where high electrical field strengths occur, leading to potential voltage breakdowns, while full casting methods increase material and process costs and reduce power density.
Innovation Solution
The stator incorporates insulation elements with a second cross-sectional area that extends further than the first, providing increased material thickness at corner sections for enhanced insulation and preventing bridging, while maintaining thinner sides for efficient insulation, formed using a mold with blind holes designed to accommodate flowable or powdery wrapping material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the immersion process is carried out to achieve greatest possible material thickness of insulation elements, then insulation thickness is improved, but bridges form between insulation elements of adjacent connecting sections increasing crack risk
Solution Approach 1:
The insulation element is designed with locally varying thickness: thicker at corner sections where high electrical field strengths occur and thinner at side sections. This local differentiation ensures adequate insulation where needed while preventing bridge formation between adjacent elements, resolving the contradiction between insulation thickness and bridge formation risk.
Solution Approach 2:
The cross-sectional shape of the insulation element is optimized by extending additional surfaces further than adjacent sides in directions away from the connecting section. This dimensional optimization allows the insulation element to provide maximum thickness at critical corner sections while maintaining appropriate spacing at sides, preventing bridges while ensuring insulation effectiveness.
2Reliability
If full casting is used to cast all connecting sections directly onto the stator core, then insulation is improved, but material and process costs increase and power density decreases
Solution Approach 1:
The insulation solution is segmented into individual insulation elements that are applied separately to each connecting section or group of connecting sections, rather than using a single full casting. This segmentation reduces material consumption and simplifies the manufacturing process while maintaining adequate insulation, resolving the contradiction between insulation quality and manufacturing cost.
3Reliability
If full casting is used, then insulation is improved, but heat dissipation from connecting sections becomes more difficult
Solution Approach 1:
By using separate insulation elements instead of a full casting, the connecting sections remain partially exposed or have improved thermal pathways. This segmentation prevents the casting body from acting as a thermal barrier, allowing heat to dissipate more effectively from the connecting sections while insulation is maintained through the optimized insulation element geometry.
Data Source
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AI summary
Stator (1) for an electric machine (101), comprising: - a stator core (2) having an axial end face (3); - several shaped conductors (6) projecting from the stator core (2) at the end face (3) and each having at least one end section (8) comprising a free end (7) of the shaped conductor (6) at the end face (3), wherein arrangements of at least two of the end sections (8) are electrically conductive and mechanically connected to one another in such a way that the arrangement forms a connecting section (9) comprising a first cross-sectional area (16) lying in a predetermined cross-sectional plane (15), the corner sections (17) and side sections (18) lying between the corner sections; and - several insulating elements (14) each enclosing at least one of the connecting sections (9) and being made of an electrically insulating material;wherein each insulation element (9) has a second cross-sectional area (19) lying in the cross-sectional plane (15), which has an additional area (20) for each corner section (17) of the first cross-sectional area (16) of the connecting section (9) enclosed by the insulation element (14) and sides (21) lying between the additional areas (20), wherein each of the additional areas (20) extends further in a direction away from the first cross-sectional area (16) than the sides (21) which adjoin the additional area (20).