Laminated Steel Rotor Stack Assembly With Thin-Film Slot Coating
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Solution Overview
Problem
Existing rotor assemblies made of aluminum face challenges in achieving high conductivity and preventing welding and inner laminar shorting during the casting process, particularly in laminated steel stacks with aluminum alloy cages.
Innovation Solution
Application of a thin-film composite, such as a copper and carbon nanotube composite, to the slot surfaces of a laminated steel stack, which improves adhesion with cast conductive bars and enhances conductivity, while using a transfer member to facilitate precise placement and adhesion during the casting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin-film composite is applied to slot surfaces to improve conductivity and adhesion, then the electrical conductivity and power density of the rotor assembly are enhanced, but the manufacturing complexity and process time increase due to the additional coating step
Solution Approach 1:
The thin-film composite is applied to the slot surfaces before the casting process, preparing the surface in advance to ensure optimal adhesion and conductivity. This preliminary action allows the composite to be properly positioned and bonded before the aluminum alloy is introduced, resolving the contradiction by establishing the conductive layer early in the process sequence
Solution Approach 2:
The thin-film composite acts as an intermediary layer between the steel slot surface and the aluminum alloy cage structure. This intermediate layer improves electrical conductivity and adhesion while preventing direct contact that would cause welding, thus enhancing reliability without requiring complete process redesign
2Reliability
If a thin-film composite is applied to slot surfaces to prevent welding and inner laminar shorting, then the reliability of the rotor assembly is improved, but the manufacturing precision requirements increase for proper film placement and thickness control
Solution Approach 1:
The patent utilizes a thin-film composite that can conform to the slot surfaces while providing the necessary protective and conductive functions. The thin film nature allows it to be applied with controlled thickness while maintaining flexibility in placement, reducing the precision requirements compared to thicker or rigid coatings
Solution Approach 2:
The thin-film composite serves as a consumable protective layer that is applied specifically for its protective function during casting and then remains as a permanent thin coating. The use of a thin, disposable-like film reduces the need for high-precision application equipment compared to thicker, reusable coatings
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 thin-film composite enhances the conductivity and power density of electric machines, reduces welding and inner laminar shorting, and improves the performance of rotor assemblies at high frequencies and low speeds.
Implementation Method 1
positioning a thin-film composite with a transfer member into engagement with a slot surface
Implementation Method 2
The thin-film composite includes an ultra-conducting composite having carbon nanotubes with a thickness of less than or equal to 25 microns
Data Source
AI summary
A method of making a rotor assembly includes positioning a thin-film composite with a transfer member into engagement with a slot surface of a corresponding slot of a multitude of slots. The slots are formed around a perimeter of a laminated steel stack with each of the slots in the laminated steel stack being defined by a slot surface. The method also includes placing the laminated steel stack in a casting mold, having cavities for defining a pair of end rings on opposite ends of the laminated steel stack that are in fluid communication with the slots.