Slip Ring Brush Holder Cooling for Higher Power Density
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Solution Overview
Problem
The increasing power outputs of dynamo-electric machines, such as wind turbine generators, lead to excessive heating of slip ring systems due to higher current loads, which can damage components and require larger designs, increasing material costs and overall dimensions.
Innovation Solution
A slip ring system with improved cooling performance, utilizing ventilation systems and surface-enlarging structures on brush pockets, such as ribs or knobs, to enhance airflow and direct it towards heat sources, supported by fans, ensuring uniform thermal stress and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the slip ring system is designed with larger outer diameters and larger brush holders to counteract rising temperatures, then the maximum permissible temperatures are not exceeded, but the material costs and overall dimensions increase significantly
Solution Approach 1:
The patent introduces a third dimension by adding axial depth to the brush pockets through the form of ribs or knobs extending into the pocket. This increases the cooling surface area without increasing the radial or circumferential dimensions, thus cooling the brushes more effectively without expanding the overall working area of the slip ring system
Solution Approach 2:
The cooling structures (ribs or knobs) are placed locally at specific positions within the brush pockets where cooling is most needed. This localized approach enhances cooling performance at critical heat generation points without requiring a complete redesign or overall enlargement of the brush holders
2Power
If more brushes are used to handle higher current loads, then the power transmission capacity increases, but the heat generation and cooling requirements increase, leading to larger system dimensions
Solution Approach 1:
The patent enhances the cooling capability locally at each brush position by adding ribs or knobs to the brush pockets. This allows each individual brush to be cooled more effectively, enabling the system to handle higher current loads with the same number of brushes or fewer brushes, thus maintaining power transmission capacity without proportionally increasing cooling requirements
3Temperature
If the cooling airflow is increased to reduce temperatures, then the operating temperatures decrease, but the system complexity and material costs increase
Solution Approach 1:
The patent uses simple geometric features (ribs or knobs) integrated into the existing brush pocket structure rather than adding separate complex cooling devices. These structures create turbulence and increase surface area for heat dissipation using passive geometry, requiring minimal additional ventilation system complexity while effectively reducing temperatures
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
Reduces operating temperatures, allowing for smaller dimensions and higher power transmission with fewer brushes, while maintaining component integrity and reducing material costs.
Implementation Method 1
The ventilation system directs air within the slip ring system, which can be either closed or open, in such a way that brush holders, and/or brush pockets and/or brushes are cooled. This is achieved by providing the necessary cooling airflow, generated by radial and/or axial fans, within or on the slip ring system.
Implementation Method 2
By increasing the surface area of the brush pockets by means of ribs or knobs on the surface of the brush pockets, as well as optionally recesses in the brush pockets, the cooling surface of the brush pockets and/or the area of the brushes exposed to a cooling airflow is increased.
Implementation Method 3
The outside air, which is drawn into the slip ring system as cooler air through the cooling openings, is guided within the slip ring system via cooling air ducts or guides, directly to the brush pocket and/or the brush holder, and possibly to the brushes themselves.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a brush holder (1) of a slip ring assembly (13) of an electrically induced dynamoelectric machine (14), the brush holder (1) comprising means for cooling brushes (8) in the brush holder (1) and/or for cooling the brush holder (1).