Rotating Machine Cooling via Segmented Stator and Radial Air Gaps
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Solution Overview
Problem
Highly utilized rotating electrical machines, particularly three-phase machines, face challenges in cooling due to limited rotor diameter and uneven temperature distribution, with existing cooling methods either restricting rotor diameter, being complex and expensive, or causing additional heating of thermally sensitive components like machine bearings.
Innovation Solution
A cooling system with radial gaps between partial laminated cores, utilizing open and closed axial channels in the stator core to facilitate direct cooling of the rotor, ensuring even temperature distribution and minimizing heating of machine bearings, while allowing for reduced rotor diameter and increased torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If axial cooling channels are used in the rotor, then cooling effect is improved, but rotor diameter cannot be reduced
Solution Approach 1:
The rotor is divided into multiple partial laminated cores with radial gaps between them, allowing cooling medium to flow through the gaps. This segmentation enables cooling without requiring large axial channels that would increase rotor diameter.
Solution Approach 2:
The cooling approach transitions from axial cooling channels (one dimension) to radial gaps between partial laminated cores (another dimension). The cooling medium flows radially through the gaps between partial laminated cores, achieving cooling without increasing rotor diameter.
2Temperature
If liquid cooling is used, then cooling effect is improved, but device complexity and cost increase
Solution Approach 1:
The invention uses air cooling instead of liquid cooling, utilizing pneumatic principles. Cooling medium (air) is supplied through the housing and flows through the radial gaps between partial laminated cores, eliminating the need for complex liquid cooling systems with seals and channels.
Solution Approach 2:
The complex liquid cooling system is extracted and replaced with a simpler air cooling system. The patent removes the need for liquid cooling channels, seals, and associated complexity by using air as the cooling medium that can be supplied through the housing.
3Temperature
If conventional cooling is used, then cooling is achieved, but uneven temperature distribution occurs
Solution Approach 1:
Different regions of the rotor are cooled differently through the radial gaps between partial laminated cores. The cooling medium flows through specific radial gaps to cool specific areas, creating localized cooling zones that address hot spots and achieve more uniform temperature distribution.
Solution Approach 2:
The rotor is segmented into multiple partial laminated cores with cooling medium supplied to different segments through radial gaps. This allows independent cooling of different rotor regions, improving temperature distribution uniformity.
4Temperature
If cooling channels are arranged axially in stator core, then cooling is achieved, but intensive cooling of both stator and rotor cannot be achieved
Solution Approach 1:
The cooling system adds a radial dimension to the cooling medium flow path. Air is supplied axially through the housing and then flows radially through the gaps between partial laminated cores, creating a two-dimensional cooling flow pattern that intensifies cooling of both stator and rotor.
Solution Approach 2:
The stator core is divided into multiple partial laminated cores with radial gaps between them. This segmentation allows cooling medium to flow through the gaps and cool both the stator laminated core and rotor simultaneously, achieving intensive cooling that axial channels alone cannot provide.
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 system achieves intensive and even cooling, reducing motor inertia by 43% and increasing torque by 30%, while preventing additional heating of thermally sensitive parts and maintaining a constant temperature distribution across the stator and rotor cores.
Implementation Method 1
Air-cooled designs are shown in EP 0 522 210 A1, EP 0 118 802 A1 and DE 43 20 559 A1
Implementation Method 2
intensive cooling of the laminated rotor core, the implementation of such a machine design therefore requires, in particular, optimum cooling of the laminated stator core
Implementation Method 3
The cooling of the rotating rotor is particularly problematic, since the liquid is thrown outwards by the centrifugal effect
Data Source
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AI summary
The invention relates to a cooling system for highly utilized rotating electrical machines, comprising a laminated stator and rotor core consisting of partially laminated cores. The aim of the invention is to provide a cooling system that evacuates the heated cooling medium as fast as possible from the machine, ensures a constant temperature distribution and prevents additional heating of the machine bearings. To achieve said aim, the laminated stator core (1) and laminated rotor core (19) respectively comprise several partially laminated cores having the same length. The partially laminated cores are located at a distance from one another by means of guiding devices and spacer segments. Axial inflow channels (2) and axial outflow channels (3) are distributed over the circumference at the back of the laminated stator core (1). The outflow channels (3) have a closed configuration on both sides. The number of the inwardly directed webs of the guiding device and spacer segments (4) corresponds to the number of inflow (2) and outflow channels (3). Partially laminated stator cores having closed channels (7) are in a combined arrangement with partially laminated stator cores having open and closed channels (8) so that each of the closed channel sections continuously form inflow channels (2) and outflow channels (3). With respect to the design of the housing of the cooling system, radial outflow openings (16) are arranged in positions of the partially laminated stator core (1) where the open channels are located. According to the invention, the cooling system can be used for highly utilized rotating electrical machines.