Stator Cooling Duct Layout to Cut Drag and Electrical Risk
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Solution Overview
Problem
Existing stator cooling systems for electric motors are inefficient and pose safety risks due to electrical conductivity issues, leading to drag loss and potential electrical shocks, especially with water-based systems, and inefficiencies in oil-based systems that introduce oil directly on stator backs or copper windings.
Innovation Solution
A semi-closed circuit stator cooling system with an inner and outer cooling duct configuration, where the inner ducts are closer to the center axis and outer ducts are closer to the surface, using endplates with inlet and outlet jackets and fingers to direct coolant flow without direct contact with copper windings, utilizing oil or other non-conductive fluids to reduce drag and enhance safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water-based cooling systems are used, then cooling efficiency is improved, but electrical safety deteriorates due to risk of electrical short or shock
Solution Approach 1:
The patent introduces a non-conductive fluid as an intermediary substance between the cooling system and the electrical components. This mediator allows heat transfer to occur while preventing electrical conduction, thus resolving the contradiction between cooling efficiency and electrical safety. The non-conductive fluid circulates through channels in the stator core, providing effective cooling without creating electrical short circuits or shock hazards.
2Temperature
If oil is introduced directly on stator back or copper windings, then cooling is achieved, but drag loss increases due to high-velocity rotor rotation
Solution Approach 1:
The patent segments the cooling approach by creating separate cooling zones: one for the stator core and another for the copper windings. The stator core is cooled through integrated channels, while the copper windings are cooled by non-conductive fluid circulating in dedicated channels within the stator assembly. This segmentation allows effective cooling of both components without introducing oil onto rotating surfaces, thereby avoiding drag loss while maintaining cooling effectiveness.
3Reliability
If existing oil-based cooling systems are used, then electrical safety is improved, but cooling efficiency deteriorates due to drag loss and improper cooling location
Solution Approach 1:
The patent applies local quality by optimizing the cooling approach for different locations within the stator assembly. Non-conductive fluid is specifically directed to areas of highest heat generation, such as the copper windings and stator core, through strategically placed channels. This localized cooling approach maximizes thermal management efficiency while maintaining electrical safety, overcoming the limitations of generic oil-based systems that may not target critical heat zones effectively.
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 improves efficiency by reducing copper winding temperatures by 15-20% and overall cycle efficiency by 1%, while ensuring safety by preventing electrical conductivity and minimizing drag, resulting in significant energy savings and safer operation.
Implementation Method 1
directing coolant from the coolant inlet to an inlet jacket... directing coolant from the inlet jacket to an inlet finger... directing coolant from the inlet finger to an inner cooling duct
Implementation Method 2
directing coolant from the inner cooling duct to an outlet finger... directing coolant from the outlet finger to an outlet jacket... directing coolant from the outer cooling duct to a drainage jacket
Data Source
AI summary
A stator can comprise a stator body comprising an inner cooling duct, and an outer cooling duct, wherein the inner cooling duct is located closer to a center axis of the stator body than the outer cooling duct, a first endplate received at a first end of the stator body, the first endplate comprising an inlet jacket circumferentially located within the first endplate, an inlet finger fluidly connected to the inlet jacket, and a drainage jacket circumferentially located within the first endplate, a second endplate received at a second end of the stator body, the second endplate comprising an outlet jacket circumstantially located within the second endplate, and an outlet finger fluidly connected to the outlet jacket, wherein the inner cooling duct fluidly connects the inlet jacket to the outlet finger, and wherein the outer cooling duct fluidly connects to the outlet jacket to the drainage jacket.