Pressurized Electric Motor Windings for High-Altitude Corona Control
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Solution Overview
Problem
High voltage and high altitude conditions in aircraft lead to increased occurrences of corona discharges in tightly wound conductor windings due to reduced atmospheric pressure, making existing methods of increasing conductor distance and insulation impractical.
Innovation Solution
An electric motor with a fan that generates increased internal pressure around conductor windings by blowing gas through a restricted flow path, reducing the need for additional parts and insulation thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the distance between conductors is increased to mitigate corona discharge, then corona discharge is reduced, but the packaging size increases and conductor windings cannot be tightly wound
Solution Approach 1:
The patent changes the pressure parameter inside the motor housing by using a fan to force air circulation and create positive pressure. This pressure change increases the dielectric strength of the air insulation between conductors, allowing tight winding while preventing corona discharge. The pressure parameter is controlled by the fan's operation relative to the motor's operation.
2Object-affected harmful factors
If insulation thickness is increased to mitigate corona discharge, then corona discharge is reduced, but the packaging size increases and conductor windings cannot be tightly wound
Solution Approach 1:
The patent changes the pressure parameter inside the motor housing to enhance the insulating capability of air. By maintaining positive pressure and increasing air density, the breakdown voltage of the air insulation increases, effectively replacing the need for thicker physical insulation layers and allowing compact motor design.
3Stress or pressure
If a hermetically sealed interior is used to maintain pressure, then internal pressure is maintained, but the motor complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The patent uses a dynamic pressure maintenance system where a fan continuously circulates air to maintain positive pressure, replacing static hermetic sealing. The fan is coupled to the motor shaft, so pressure maintenance is dynamic and tied to motor operation, simplifying the housing structure while achieving the same pressure maintenance goal.
4Object-affected harmful factors
If the fan is operated continuously to maintain pressure, then corona discharge is prevented, but energy consumption increases
Solution Approach 1:
The patent implements periodic or conditional fan operation based on motor operational status. The fan is coupled to the motor shaft through a one-way clutch or direct coupling, ensuring the fan operates only when the motor is running. This synchronized operation prevents corona discharge during high-voltage operation while minimizing unnecessary energy consumption during idle periods.
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 solution effectively mitigates corona discharges by maintaining or exceeding atmospheric pressure, allowing for reduced spacing between conductor windings and minimizing packaging size while optimizing conductor insulation.
Implementation Method 1
The flow path is restricted to increase a pressure difference between the interior of the electric motor and an exterior of the electric motor
Data Source
AI summary
An electric motor can automatically generate an internal pressure around conductor windings of the stator. The electric motor can be used on an electric aircraft or other application having variable atmospheric pressure. The electric motor includes a fan configured to blow the gas into a flow path to generate increased internal pressure about the conductor windings. The fan may be mounted to the rotator of the electric motor. The flow path is restricted to increase the pressure difference of the air entering the electric motor.