Air-Cooled Electric Motor Ejector Cooling for Stator Overheating
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Solution Overview
Problem
Existing electric motors in aircraft Environmental Control Systems (ECS) face overheating issues due to limited cooling airflow, leading to Cabin Air Compressor (CAC) operational failures.
Innovation Solution
An air cooled electric motor design that utilizes compressor seal leakage and bearing cooling airflow as a secondary stream, injected at higher velocity to increase stator cooling airflow through an ejector effect, enhancing airflow by 10% without impacting CAC performance or power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cooling airflow design is used, then the motor structure is simple, but the stator overheats and CAC operational failures occur
Solution Approach 1:
The patent implements nested cooling cavities within the motor structure. The separator plate cavity is positioned within the motor housing, and the stator outlet cavity is nested within the separator plate cavity. This nested arrangement allows multiple cooling functions to be integrated within the existing motor structure without significantly increasing external dimensions or overall complexity, while effectively increasing cooling airflow to the stator.
Solution Approach 2:
The separator plate acts as an intermediary component that divides the motor cooling structure into distinct cavities. It separates the separator plate cavity from the stator outlet cavity, allowing independent control and optimization of airflow paths. This intermediary structure enables the system to achieve improved cooling reliability while maintaining manageable structural complexity through modular design.
2Temperature
If cooling airflow is increased to prevent overheating, then stator cooling effectiveness improves, but motor structure complexity increases
Solution Approach 1:
The patent segments the cooling airflow path into distinct cavities and flow paths. The separator plate cavity receives airflow from compressor seal leakage and bearing cooling, while the stator outlet cavity is dedicated to stator cooling. This segmentation allows each cavity to be optimized for its specific function, effectively lowering stator temperature while keeping each individual cavity structurally simple and manageable.
Solution Approach 2:
The separator plate cavity serves multiple functions: it receives compressor seal leakage airflow, receives bearing cooling airflow, and directs combined airflow to the stator outlet cavity. This multi-functionality allows the system to achieve improved stator cooling without adding separate dedicated structures for each airflow source, thereby limiting the increase in overall structural complexity.
3Reliability
If additional cooling components are added to increase airflow, then cooling effectiveness improves, but weight increases
Solution Approach 1:
The patent merges multiple cooling functions into the existing motor structure. The separator plate cavity and stator outlet cavity are integrated within the motor housing, and the cooling airflow paths are combined with the existing compressor seal leakage and bearing cooling systems. This merging approach achieves improved cooling effectiveness without adding separate external cooling components that would increase motor weight.
Solution Approach 2:
The system utilizes self-service cooling by directing compressor seal leakage airflow and bearing cooling airflow into the separator plate cavity, which then supplies the stator outlet cavity. These existing airflow sources, which would otherwise be wasted, are repurposed to cool the stator, eliminating the need for additional powered cooling components that would add weight to the motor.
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 design effectively increases stator cooling airflow by 10% using a low-weight, low-impact approach, ensuring efficient operation of the CAC and ECS without additional power consumption or weight penalties.
Implementation Method 1
the separator plate is disposed to create high pressure area within the separator plate cavity and a low pressure area proximate the stator outlet cavity
Implementation Method 2
utilizes compressor seal leakage and bearing cooling airflow as a secondary stream, injected at higher velocity to increase stator cooling airflow through an ejector effect
Implementation Method 3
direct a cooling airflow over the stator outer diameter to cool the stator
Data Source
AI summary
A method for increasing stator cooling airflow in an air cooled electric motor is provided, wherein the air cooled electric motor includes a compressor outlet housing having a motor cavity separator wall and a separator plate defining a separator plate opening, wherein the compressor outlet housing defines a separator plate cavity and a compressor rotor back-face cavity configured to receive a back-face cavity airflow. The motor cavity separator wall separates the separator plate cavity from the compressor rotor back-face cavity and defines a motor cavity separator wall through-hole which communicates the separator plate cavity with the compressor rotor back-face cavity and a motor cooling housing including a motor cooling outlet structure which defines a stator outlet cavity, wherein the separator plate is disposed to separate the stator outlet cavity from the separator plate cavity.