Air-Cooled Electrical Machine Stator Cooling Cavity
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Solution Overview
Problem
Large electrical machines face challenges in heat dissipation due to a small surface-to-power ratio and harsh operating conditions, where traditional cooling methods like air or liquid circulation are inefficient and add weight, especially when ambient air circulation is restricted.
Innovation Solution
An air-cooling arrangement within an electrical machine featuring stacked laminate-plates supported by structural elements, with a fan circulating air through a joint cavity and an air-to-liquid heat-exchanger to maintain continuous cooling, reducing the need for large gas-to-air or gas-to-water heat-exchangers and minimizing additional power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a liquid cooling system with cooling channels is used in the stator, then heat transfer from metal-windings is improved, but thermal contact between laminate-plates and cooling-channels deteriorates due to thermal expansion differences
Solution Approach 1:
The patent introduces an intermediary substance (thermal paste or similar thermal conductive material) between the laminate-plates and cooling-channels to compensate for thermal expansion differences. This intermediary maintains reliable thermal contact despite differential expansion, ensuring consistent heat transfer from the metal-windings through the laminate-plates to the cooling-medium.
2Temperature
If air circulation cooling is used without housing, then cooling efficiency is improved, but protection against harsh environmental conditions deteriorates
Solution Approach 1:
The patent introduces a controlled intermediary cooling atmosphere (inert gas or filtered air) within the enclosed housing. This intermediary medium allows heat transfer from the metal-windings while protecting the internal components from harsh external environmental conditions, effectively decoupling the cooling function from direct environmental exposure.
3Temperature
If large heat-exchangers are used for cooling, then heat dissipation is improved, but device complexity and weight increase
Solution Approach 1:
The patent segments the heat dissipation function into multiple distributed cooling channels throughout the stator structure. Instead of using a single large heat-exchanger, the cooling function is distributed across numerous smaller channels that contact the laminate-plates, achieving equivalent or superior heat dissipation with reduced overall complexity and weight.
Solution Approach 2:
The patent transitions from external heat exchange to internal heat exchange by embedding cooling channels within the stator's laminate-plate structure. This dimensional integration allows heat dissipation to occur throughout the volume of the stator rather than at its surface, dramatically improving heat transfer efficiency while reducing the size of dedicated heat-exchanger components.
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 solution provides efficient cooling with reduced weight and complexity by maintaining continuous air flow through heat-generating parts and utilizing a compact liquid cooling system, enhancing thermal contact and heat transfer while minimizing additional structural components.
Implementation Method 1
an air-cooling-arrangement, which is arranged and used to circulate a gaseous medium for cooling purposes inside the joint cavity
Implementation Method 2
an air-to-liquid-heat-exchanger is located inside the joint cavity, so heat is removed from the cavity by a liquid-cooling-arrangement
Implementation Method 3
the heat is transferred from the metal-windings through the laminate-plates to the cooling-medium by conduction
Data Source
AI summary
An air-gap is between a rotor and a stator. The stator comprises a number of stacked laminate-plates. The laminate-plates are positioned and fixed by a structural support and by end-plates in relation to a central-part of the stator to achieve the air-gap. A cavity is formed by the end-plates, the central-part of the stator, the air-gap and an internal surface of the rotor. An air-cooling arrangement is arranged and used to circulate a gaseous medium for cooling purposes inside the cavity.