Offset Radial Cooling Slots in Electrical Machines
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Solution Overview
Problem
Electrical machines in wind turbines face challenges in reducing noise emissions, particularly due to the alignment of radial cooling slots in the stator and rotor, which can generate continuous cooling channels and increase noise, and existing solutions have limitations in effectively managing airflow and noise reduction.
Innovation Solution
The electrical machine design features offset radial cooling slots between the stator and rotor, with varying axial lengths and numbers of cooling slots in each active part, ensuring the same overall iron length and utilizing a cooling channel that redirects coolant flow to enhance turbulence and reduce friction losses, while maintaining uniform air resistance and cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If radial cooling slots in stator and rotor are aligned, then cooling efficiency is improved, but noise emissions increase due to continuous cooling channels
Solution Approach 1:
The patent applies asymmetry by deliberately misaligning the radial cooling slots between stator and rotor. The cooling slots are positioned at different angular positions, creating an asymmetric configuration that breaks the continuous cooling channel path. This asymmetric arrangement reduces noise emissions by preventing the formation of continuous airflow paths while still allowing effective cooling through the individual slots.
2Object-generated harmful factors
If cooling slots are offset to reduce noise, then noise emissions are reduced, but cooling efficiency decreases due to disrupted airflow
Solution Approach 1:
The patent applies segmentation by dividing the cooling system into discrete, separated cooling slots in the stator and rotor. Rather than having continuous or aligned cooling paths, the cooling slots are segmented and positioned at different angular locations. This segmentation disrupts continuous airflow paths (reducing noise) while maintaining effective cooling through the distributed slot configuration.
3Object-generated harmful factors
If varying axial lengths of laminations are used to create offset cooling slots, then noise is reduced through disrupted cooling channels, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by varying the axial lengths of individual laminations at specific locations to create the offset cooling slot configuration. Rather than requiring complex overall design changes, the solution implements local variations in lamination dimensions. This allows the offset cooling slot geometry to be achieved through controlled local differences in lamination axial lengths, managing manufacturing complexity while achieving the noise reduction goal.
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 design effectively reduces noise emissions and improves cooling efficiency, ensuring compliance with noise limits and optimizing the use of iron in the machine, while maintaining low air resistance and cost-effectiveness.
Implementation Method 1
radial cooling slots, through which a cooling medium can flow, are produced to guarantee adequate cooling of the electrical machine
Implementation Method 2
the radial cooling slots in the first active part are offset in the axial direction in relation to one another in comparison to the radial cooling slots in the second active part
Data Source
AI summary
An electrical machine includes a first active part and a second active part. Both the first active part and the second active part have a plurality of laminated sub-cores, with each laminated sub-core having a plurality of individual laminations. Each lamination is defined by an axial width. The laminated sub-cores are mutually spaced in an axial direction such that a respective radial cooling slot is formed between two adjacent laminated sub-cores. The radial cooling slots in the first active part are offset in the axial direction in relation to one another in comparison to the radial cooling slots in the second active part, and the sum of the axial widths of all individual laminations in the first active part corresponds to the sum of the axial widths of all individual laminations in the second active part.