Electrical Machine Humidity Estimation Using Temperature Change
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Solution Overview
Problem
Existing methods fail to effectively measure relative humidity inside electrical machines, which is crucial for maintaining machine reliability, as excessive moisture can degrade insulation and cause motor failure, and installing humidity sensors requires physical modifications.
Innovation Solution
Estimate relative humidity by monitoring the rate of change of temperature inside the machine using engineered logic, calculating the ratio of measured ROC to a reference ROC, and comparing it to known specific heat values to determine humidity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If humidity sensors are installed inside the machine frame, then relative humidity measurement capability is improved, but device complexity and ease of manufacture deteriorate due to required physical modifications
Solution Approach 1:
The patent uses temperature as an intermediary parameter to indirectly measure relative humidity. By monitoring temperature changes and applying thermodynamic relationships, the system derives humidity information without requiring direct humidity sensing inside the machine frame, thus avoiding physical modifications while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical/physical humidity sensor installation with a computational approach using temperature measurements and thermodynamic calculations. This substitution eliminates the need for physical sensor integration while achieving the same measurement objective
2Device complexity
If temperature monitoring is used to estimate humidity, then device complexity is reduced, but measurement precision deteriorates compared to direct humidity sensing
Solution Approach 1:
The patent transforms the measurement parameter from direct humidity sensing to temperature-based indirect measurement. By changing the measurement parameter and using thermodynamic relationships, the system achieves acceptable precision while simplifying the overall device complexity
Solution Approach 2:
The patent discards the need for direct humidity measurement and recovers humidity information through temperature data and thermodynamic calculations. This approach trades direct measurement precision for system simplicity while recovering sufficient accuracy for practical applications
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
Enables reliable humidity estimation without modifying the machine, enhancing insulation reliability and preventing potential damage by safely shutting down or alerting for maintenance when threshold values are exceeded.
Implementation Method 1
A ratio of the measured ROC to the reference ROC is then calculated. The ratio is equal to an average specific heat of the electrical machine
Data Source
AI summary
A method for estimating relative humidity inside an electrical machine includes determining a measured rate of change (ROC) of temperature inside an electrical machine. A ratio of the measured ROC to a reference ROC is calculated, where the ratio is equal to an average specific heat of the electrical machine. The average specific heat of the electrical machine and an air temperature value are then compared to known specific heat values of dry air and water corresponding to a known relative humidity values for a range of air temperatures. A relative humidity value inside the electrical machine is estimated based on the comparison.