Electric Rotating Machine Insulation Spacer Thermal Expansion
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Solution Overview
Problem
Existing electric rotating machines with concentrated winding configurations face challenges in achieving sufficient cooling performance due to gaps between the stator coil and insulation material, which degrade thermal conductivity and insulation quality, despite previous attempts to address these issues.
Innovation Solution
Incorporating a spacer with electric insulation and a higher coefficient of linear expansion than the stator core, placed between adjacent stator coils, which reduces clearances and enhances thermal contact when heated, improving cooling performance across various cooling methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the insulation material is increased to ensure electric insulation performance, then insulation quality is improved, but thermal resistance increases and cooling performance degrades
Solution Approach 1:
The insulation material is designed with non-uniform thickness: thicker at the bottom of the coil winding to ensure electric insulation, and thinner at the top to reduce thermal resistance. This local variation in thickness optimizes both insulation quality and cooling performance by placing material where it is most needed electrically while minimizing its thermal barrier effect.
2Ease of manufacture
If a gap occurs between the teeth and insulation material due to increased bending radius, then the coil can be wound around rectangular teeth, but thermal resistance increases and cooling performance degrades
Solution Approach 1:
The cross-sectional shape of the insulation material is changed from a standard rectangular form to a custom shape with a curved surface that matches the bending radius of the coil. This parameter change in the insulation material's geometry eliminates gaps between the coil and insulation material, improving thermal contact and cooling performance while maintaining ease of coil winding.
3Temperature
If the insulation material is made thinner to improve cooling performance, then thermal resistance decreases, but electric insulation performance may be compromised
Solution Approach 1:
The insulation material is designed with non-uniform thickness: thicker at the bottom of the coil winding to ensure electric insulation, and thinner at the top to reduce thermal resistance. This local variation in thickness optimizes both insulation quality and cooling performance by placing material where it is most needed electrically while minimizing its thermal barrier effect.
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 solution effectively improves cooling performance while maintaining insulation quality and increasing output power without increasing machine size, applicable to both indirect and direct cooling methods.
Implementation Method 1
The spacer has a coefficient of linear expansion greater than that of the stator core
Data Source
AI summary
An electric rotating machine having high cooling performance is provided. The electric rotating machine is configured to include a rotor rotating around a rotational axis; and a stator disposed to face the circumferential surface of the rotor. The stator includes a stator core having a cylindrical core back and a plurality of teeth radially extending from the core back, and a stator coil wound around the teeth in concentrated winding via an insulation material. A spacer having electric insulation performance is attached between the stator coils each wound around the respective teeth adjacent to each other. The spacer has a coefficient of linear expansion greater than that of the stator core.