High-Temperature Stator Construction Using Ceramic Insulation
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Solution Overview
Problem
Electrical machines face limitations in operating temperatures due to polymeric insulation materials, which cannot exceed 300°C, and inorganic insulation materials like ceramic cloths or coatings are bulky, poorly conductive, and prone to thermal expansion issues and moisture absorption, making them unsuitable for high-temperature applications such as gas turbine engines.
Innovation Solution
The use of axial conductors within tubular ceramic insulation members and ceramic end turn wafers with conductive link pieces, along with magnesium oxide insulation, to create a compact, hermetically sealed motor winding that can withstand high temperatures, allowing for efficient thermal management and preventing leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymeric insulation material is used for electrical conductor windings, then the manufacturing process is simple and cost-effective, but the maximum operating temperature is limited to approximately 200-300°C
Solution Approach 1:
The patent changes the fundamental material parameter from polymeric to inorganic insulation, enabling the electrical machine to operate at temperatures of 400-500°C and above, thereby resolving the temperature limitation while maintaining manufacturing feasibility through standardized inorganic insulation components
Solution Approach 2:
The patent employs composite construction combining inorganic insulation material with ceramic coatings or ceramic cloth and inorganic cement, creating a composite insulation system that provides both high temperature resistance and electrical insulation properties necessary for 400-500°C operation
2Temperature
If inorganic insulation material such as ceramic cloth or ceramic coating is used, then the maximum operating temperature can exceed 300°C, but the insulation material becomes bulky limiting conductor packing density
Solution Approach 1:
The patent applies thin film ceramic coatings directly to the electrical conductors, providing necessary electrical insulation and high temperature resistance (400-500°C) while maintaining compact dimensions and high conductor packing density, thereby resolving the bulkiness issue of traditional ceramic insulation
3Reliability
If inorganic insulation material with poor thermal conductivity is used, then electrical insulation is provided, but thermal management of the electrical conductor becomes difficult
Solution Approach 1:
The patent applies different material properties to different locations: ceramic coatings provide electrical insulation where needed, while the inorganic cement formulation is optimized for thermal conduction, creating a multi-functional insulation system that simultaneously provides electrical isolation and thermal management for 400-500°C operation
4Reliability
If porous inorganic cement is used for potting, then the inorganic insulation material is provided, but the porous nature allows fluids such as water, oil or lubricant to be absorbed
Solution Approach 1:
The patent modifies the inorganic cement formulation to eliminate porosity, creating a dense, non-absorbent potting material that prevents fluid penetration while maintaining electrical insulation stability and thermal conduction properties for high temperature 400-500°C operation
5Temperature
If inorganic insulation material is used, then high temperature resistance is achieved, but thermal expansion mismatch causes damage during thermal cycling
Solution Approach 1:
The patent creates a composite inorganic insulation system combining ceramic coatings, ceramic cloth, and specially formulated inorganic cement that has matched thermal expansion properties, allowing the insulation assembly to withstand repeated thermal cycling at 400-500°C without damage from expansion mismatch
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 configuration enables electrical machines to operate at temperatures up to 400-500°C, simplifying machinery design and eliminating the need for conventional bearings and oil systems, while maintaining insulation integrity and thermal efficiency.
Implementation Method 1
each axial conductor being disposed within a tubular axial insulation member, the tubular axial insulation members being disposed within a stack of laminations
Implementation Method 2
the inorganic insulation material may be based on ceramic cloths or ceramic coatings... the use of an inorganic insulation material may be based on ceramic cloth and inorganic cement
Implementation Method 3
The presence of moisture tends to degrade the electrical insulation by allowing leakage currents to earth or between turns of the electrical conductor. The presence of oil tends to degrade the electrical insulation by forming carbon also allowing leakage currents to earth or between turns of the electrical conductor
Data Source
AI summary
A stator has a field winding, the winding comprising a plurality of axial conductors connected at their ends to form at least one circuit with a number of turns. Each axial conductor is disposed within a tubular axial insulation member, the tubular axial insulation members being disposed within a stack of laminations. The axial conductors and the tubular insulation members are radially distributed at equal angles. The position of the axial conductors and the tubular insulation members is predetermined.