Liquid Cooled Permanent Magnet Rotor Balancing and Cooling
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Solution Overview
Problem
Conventional cooling techniques for electrical generators, particularly for permanent magnet rotors, are inadequate as they can lead to overheating and magnetic debris accumulation, and balancing issues due to variability in the center of mass, causing vibrations and premature wear.
Innovation Solution
A permanent magnet rotor design with a cooling liquid containment mechanism using liquid containment covers on axial rotor core ends, which includes a rotor shaft with longitudinal passages for a cooling circuit and a balancing mechanism integrated into the liquid containment covers to address both cooling and balancing challenges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling techniques (air cooling or oil spray) are used for permanent magnet rotors, then heat dissipation is achieved, but magnetic debris accumulates on the rotor and overheating occurs
Solution Approach 1:
The patent applies hydraulic cooling by circulating liquid coolant through closed-channel passages formed within the rotor core structure. The liquid coolant flows through channels defined by the interaction between the rotor core outer peripheral surface and the inner peripheral surface of the permanent magnets, effectively dissipating heat without introducing magnetic debris into the system.
Solution Approach 2:
The cooling channels are nested within the rotor core structure itself, formed by the interaction between the rotor core outer peripheral surface and the inner peripheral surface of the permanent magnets. This nested design integrates the cooling function into the existing rotor structure without adding external cooling components that could introduce debris.
2Stability of the object's composition
If balancing mass is mounted on the rotor core itself (via machined bores and threaded bolts), then rotor balancing is achieved, but the rotor structure becomes more complex and manufacturing becomes more difficult
Solution Approach 1:
The rotor core serves multiple functions: it provides the structural foundation for the rotor, contains the cooling channels for heat dissipation, and incorporates the balancing function through its own mass distribution. By designing the rotor core with adjustable mass distribution capabilities, the need for separate balancing mass components and their associated mounting structures is eliminated.
Solution Approach 2:
The balancing function is merged with the rotor core structure itself rather than being implemented through separate balancing mass components. The rotor core is designed with internal voids or adjustable mass distribution features that allow it to perform both structural and balancing functions in a unified design, reducing manufacturing complexity.
3Temperature
If liquid coolant is circulated through closed-channel passages in the rotor core, then effective cooling is achieved, but the rotor core structure becomes more complex
Solution Approach 1:
The cooling channels are nested within the rotor core structure, formed by the interaction between the rotor core outer peripheral surface and the inner peripheral surface of the permanent magnets. This nested design integrates the cooling function into the existing rotor structure without adding external cooling components.
Solution Approach 2:
The rotor core is designed to serve multiple functions simultaneously: providing structural support, containing cooling channels for heat dissipation, and enabling rotor balancing through its mass distribution. This multi-functional design reduces the need for separate components and minimizes overall structural complexity.
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 dissipates heat and balances the rotor, reducing vibrations and wear while minimizing magnetic debris accumulation, providing a reliable and cost-effective solution for generators operating in various environments.
Implementation Method 1
dissipating heat from the permanent magnet rotor core at least in part by passing a cooling liquid between a shaft passage extending longitudinally in the rotor core and a plurality of core cooling passages extending longitudinally in an inner core component of the permanent magnet rotor core
Implementation Method 2
passing a cooling liquid between a shaft passage extending longitudinally in the rotor core and a plurality of core cooling passages extending longitudinally in an inner core component
Data Source
AI summary
A permanent magnet rotor for an electrical generator includes a rotor shaft and a rotor core mounted coaxially upon the rotor shaft. The rotor core defines a plurality of longitudinal core passages which include a segment of a rotor cooling circuit, and further includes a permanent magnet outer core component mounted on an inner core component and including a plurality of permanent magnets. A cooling liquid containment mechanism for the permanent magnet rotor includes a first liquid containment cover coupled to the inner core component and a second liquid containment cover coupled to the inner core component. The liquid containment covers are configured to contain cooling liquid passed from an inlet segment of the rotor cooling circuit defined by the rotor shaft into the plurality of longitudinal core passages, and thenceforth into an outlet segment of the rotor cooling circuit also defined by the rotor shaft. The liquid containment covers are mounted on the inner core component at locations radially inward of a cylindrical outer surface thereof.