Bar Wound Stator Insulation System with Overlapping Liner and Cap
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Solution Overview
Problem
Existing bar wound stators face issues with slot liners being torn or pushed out during the insertion of bar-type conductors, which compromises insulation and mechanical stability.
Innovation Solution
The use of a cuffed slot liner and an overlapping insulator cap design that insulates between the bar-type conductors and the stator core, with the cuffed end resisting push-out and increasing resistance to tearing, while the recessed features accommodate the overlapping portions without affecting the electric machine's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional slot liner is used to insulate between bar-type conductors and stator core, then insulation is provided, but the slot liner is torn or pushed out during insertion of bar-type conductors
Solution Approach 1:
The insulation system is divided into two separate components: a slot liner and an insulator cap. The slot liner remains in the slot to provide insulation against the stator core, while the insulator cap is placed over the slot liner end to protect against push-out during conductor insertion. This segmentation allows each component to specialize in protecting against specific failure modes.
Solution Approach 2:
The slot liner is pre-installed in the slot before bar-type conductors are inserted. This preliminary placement ensures insulation is already in position to prevent electrical breakdown, and the subsequent insulator cap is then added to protect the liner during the conductor insertion process.
2Reliability
If the slot liner is made longer to insulate against all wall surfaces, then insulation coverage is improved, but resistance to tearing and push-out decreases
Solution Approach 1:
The insulation function is segmented between the slot liner (providing insulation against the stator core) and the insulator cap (providing insulation against the slot walls and protecting the liner). This allows the slot liner to be shorter and more tear-resistant while achieving complete insulation coverage through the added cap component.
Solution Approach 2:
The insulator cap extends the insulation coverage in a new dimension by wrapping around the end of the slot liner and providing insulation against the slot walls, rather than simply extending the liner length in the axial direction. This dimensional approach maintains liner strength while achieving complete coverage.
3Reliability
If the slot liner and insulator cap overlap to insulate against all surfaces, then complete insulation is achieved, but device complexity increases
Solution Approach 1:
The insulation system is segmented into two simple, standardized components (slot liner and insulator cap) that can be manufactured independently and assembled in a straightforward sequence. This segmentation avoids the complexity of designing a single complex insulator while achieving comprehensive insulation coverage.
Solution Approach 2:
The insulator cap serves multiple functions: it provides insulation against the slot walls, protects the slot liner end from push-out forces, and maintains the insulation barrier continuity. This multi-functionality is achieved with a single simple component rather than multiple complex elements.
Data Source
AI summary
A bar wound stator includes a stator core defining a plurality of slots. Bar-type conductors are disposed within each slot. Each slot includes a slot liner and an insulator cap. Each slot liner includes an end portion disposed against an inner wall surface, and side portions disposed against a first wall surface and a second wall surface respectively. Each insulator cap includes a base portion disposed against an outer wall surface, and side portions disposed against the first wall surface and the second wall surface respectively. The side portions of the insulator cap in each slot overlap the side portions of the slot liner in each slot along the first wall surface and the second wall surface respectively. Each slot includes a recessed feature in each of the first wall surface and the second wall surface to accommodate the overlapping side portions of the insulator cap and the slot liner.