Electrical Machine Cooling via Rotor Shaft Radial Coolant Supply
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Solution Overview
Problem
Existing liquid cooling methods for electrical machines, such as lance cooling, are inefficient in achieving a low temperature level in both the rotor and stator, limiting the continuous output and requiring more expensive magnets for performance maintenance.
Innovation Solution
A method involving an axial and radial coolant supply system within the rotor shaft, where a coolant is guided through bores to interact directly with components, enhancing heat transmission and using non-conductive oils for efficient cooling and lubrication, allowing for cost-effective magnet use and improved cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lance cooling is used with a cooling lance inserted into the hollow rotor shaft, then the rotor shaft is accessible from only one side, but the heat removal efficiency from the rotor and stator is insufficient to achieve low temperature levels
Solution Approach 1:
The cooling system is segmented into multiple independent coolant supply lines (first radial coolant supply line, second radial coolant supply line, third radial coolant supply line, fourth radial coolant supply line) distributed at different locations in the rotor shaft, allowing coolant to be supplied to multiple regions simultaneously for more effective heat removal from both rotor and stator
Solution Approach 2:
The cooling approach transitions from a single axial lance insertion to a multi-dimensional radial coolant distribution system, where coolant is supplied radially outward through multiple bore lines positioned at different radial distances and angular locations, creating comprehensive cooling coverage in three-dimensional space
2Productivity
If conventional liquid cooling methods are used, then cooling is provided, but the continuous output of the electrical machine is limited due to insufficient temperature reduction
Solution Approach 1:
The coolant system serves multiple functions simultaneously: it cools the rotor through radial supply lines, cools the stator through direct contact in the interior chamber, and enables higher continuous output by maintaining low temperature levels across all components, making the cooling system universally effective for the entire electrical machine
Solution Approach 2:
The cooling system enables continuous operation at high output by maintaining constant low temperature levels through persistent coolant circulation through multiple radial supply lines, ensuring uninterrupted heat removal from both rotor and stator during continuous operation
3Power
If expensive magnets are used to maintain performance at higher temperatures, then performance is maintained, but the cost increases
Solution Approach 1:
The electrical machine achieves cost-effectiveness by using an integrated cooling system that maintains low temperature levels through its own internal radial coolant supply lines, eliminating the need for expensive high-temperature magnets and allowing the use of more economical magnet materials
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 method achieves a lower temperature level in electrical machines, enabling higher continuous output and reducing the need for expensive magnets, while simplifying the design by eliminating the need for seals and optimizing coolant circulation for effective heat removal.
Implementation Method 1
the coolant can interact directly with those components of the electrical machine that are to be cooled. Short and low-resistant heat conducting parts are therefore realized between those locations and/or components of the electrical machine that are to be cooled
Implementation Method 2
guiding a coolant in an axial coolant supply line which is arranged in the rotor shaft, and introducing the coolant into an interior chamber of the electrical machine
Implementation Method 3
An electrically non-conducting coolant, in particular an oil, preferably a transmission oil, is preferably used. The coolant, if it comes into direct contact with current-conducting components of the electrical machine, therefore cannot impair the operability of the electrical machine. In particular, the coolant does not bring about any short circuit
Data Source
AI summary
A method for cooling an electrical machine includes the following steps: guiding a coolant in an axial coolant supply line which is arranged in the rotor shaft, and conducting the coolant into an interior chamber of the electrical machine via a radial coolant supply line which is connected in a coolant-conducting manner to the axial coolant supply line. The electrical machine has an axial coolant supply line and at least one radial coolant supply line connected in a coolant-conducting manner to the axial coolant supply line, both of which are arranged in the rotor shaft. An interior chamber of the electrical machine is connected in a coolant-guiding manner to the radial coolant supply line.