Vacuum Gap Generator Rotor Cooling via Microchannels
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Solution Overview
Problem
Electrical generators and motors experience efficiency losses due to windage losses caused by air gaps between the rotor and stator, which also lead to arcing and corona discharge at high altitudes, and conventional cooling methods like oil sprays can exacerbate these issues.
Innovation Solution
Implementing a vacuum gap between the rotor and stator, combined with microchannels within the rotor for coolant delivery, to reduce windage losses and enhance cooling efficiency, while allowing for the use of additive manufacturing to create complex coolant pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is used to cool the rotor, then cooling is provided, but windage losses increase reducing efficiency
Solution Approach 1:
The patent removes air from the gap between rotor and stator, creating a vacuum environment. This extraction of the cooling medium eliminates windage losses while maintaining rotor cooling through alternative means (internal cooling channels), directly resolving the contradiction between cooling effectiveness and energy efficiency
Solution Approach 2:
The patent employs internal coolant channels within the rotor structure, using liquid coolant flow to provide cooling. This hydraulic cooling system replaces air cooling, enabling effective heat removal without the presence of gas in the gap, thus eliminating windage losses
2Temperature
If air gap is used between rotor and stator, then cooling is achieved, but arcing and corona discharge occur at high altitudes
Solution Approach 1:
By removing air from the rotor-stator gap to create a vacuum, the patent eliminates the gaseous medium that enables arcing and corona discharge. This extraction prevents these harmful electrical phenomena while maintaining necessary cooling through internal channels
Solution Approach 2:
The patent creates a vacuum environment (inert atmosphere without gas molecules) in the rotor-stator gap. This inert environment prevents electrical breakdown, arcing, and corona discharge that would otherwise occur in atmospheric conditions, especially at high altitudes
3Temperature
If oil spray is used for cooling, then cooling efficiency improves, but device complexity and potential for arcing increase
Solution Approach 1:
The patent removes oil spray systems entirely by creating a vacuum gap. Cooling is achieved through integrated internal channels within the rotor, eliminating the complexity of external spray systems, pumps, and associated infrastructure while maintaining effective cooling
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 vacuum gap significantly reduces windage losses, eliminates arcing and corona discharge, and improves overall efficiency by enabling effective cooling without the drawbacks of air or oil-based systems, resulting in a more compact and lightweight design.
Implementation Method 1
the gap between the rotor and the stator is evacuated to form a vacuum gap
Implementation Method 2
coolant flow through microchannels in the rotor to reduce windage losses and cooling the rotor windings
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
In one embodiment, a generator or an alternating current (AC) motor includes a stator and a rotor. The rotor is configured to rotate at least partially within the stator or around the stator and is separated from the stator by a gap having a partial vacuum. The rotor includes a shaft configured to permit a flow of coolant and a plurality of microchannels formed within the rotor. The microchannels are fluidly coupled to the shaft and are configured to permit the coolant to pass from the shaft through at least a portion of the rotor in order to provide cooling for the rotor.