Electrical Contactor End-of-Life Detection by Cumulative Energy
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Solution Overview
Problem
Existing systems for identifying the end-of-life condition of electrical contactors in aircraft propulsion systems are inadequate, often relying on switching operation counts or current measurements, which can lead to premature replacement and increased maintenance costs while failing to account for actual wear and thermal stress.
Innovation Solution
A method and system that uses a controller to measure cumulative electrical energy and switching time during contactor operations, comparing these values to predefined thresholds to accurately determine the end-of-life condition, thereby facilitating timely replacement and reducing unnecessary maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If switching operation counts are used to identify end-of-life condition, then the identification process is simple, but it leads to premature replacement and increased maintenance costs
Solution Approach 1:
The patent changes the monitoring parameter from simple switching operation counts to cumulative electrical energy (integrating voltage and current over time). This parameter transformation allows the system to account for actual thermal stress and wear conditions, improving end-of-life identification accuracy while maintaining a relatively simple implementation through standard electrical measurements and integration calculations.
2Ease of operation
If current measurements are used to identify end-of-life condition, then the measurement is straightforward, but it fails to account for actual wear and thermal stress
Solution Approach 1:
The patent transforms the measurement from simple current magnitude to cumulative electrical energy by integrating voltage and current over the switching operation time. This parameter change maintains ease of operation since voltage, current, and time are readily measurable quantities, while dramatically improving wear assessment accuracy by capturing the thermal stress and energy dissipation that actually cause contactor degradation.
Solution Approach 2:
The patent continuously monitors and integrates electrical parameters throughout the switching operation duration rather than taking discrete snapshots. This continuous measurement approach ensures that the cumulative energy calculation accurately reflects the total thermal stress and wear experienced during each switching cycle, improving measurement precision while using standard continuous measurement techniques.
3Measurement precision
If cumulative electrical energy is measured to identify end-of-life condition, then the identification accuracy is improved, but the measurement and calculation complexity increases
Solution Approach 1:
The patent changes the monitored parameter to cumulative electrical energy, which is calculated by integrating voltage and current over time. While this improves identification accuracy by reflecting actual thermal stress, the complexity is managed by using standard electrical measurements and numerical integration techniques that can be implemented with conventional sensors and processors already present in modern electrical systems.
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors electrical parameters, calculates cumulative energy, compares it against thresholds, and provides feedback for maintenance decisions. This closed-loop approach automates the complex calculation and decision-making process, reducing operational complexity while maintaining high measurement precision through continuous monitoring and adaptive threshold comparison.
Data Source
AI summary
A propulsion system includes an electrical assembly and a controller. The electrical assembly includes at least one contactor and a sensor assembly. The at least one contactor is switchable by a switching operation between an open condition and a closed condition. The controller is connected in signal communication with the sensor assembly. The controller is configured to determine, using the sensor assembly, an electrical energy of the at least one contactor for each switching operation of the at least one contactor to determine a cumulative electrical energy for the at least one contactor and identify a presence or an absence of an end-of-life condition for the at least one contactor by comparing the cumulative electrical energy to an end-of-life energy threshold. The presence of the end-of-life condition is identified where the cumulative electric energy exceeds the end-of-life energy threshold.