Rotating Component Fault Detection Using Frequency-Domain Speed Signals

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Solution Overview

Problem

Existing methods for monitoring and detecting failures in rotating components of air turbine starters, such as bearings, shafts, and gears, are inadequate in predicting component wear and failure, leading to potential engine start issues, flight delays, and maintenance challenges.

Innovation Solution

A method involving a magnetic speed sensor that transforms electrical signals from rotating components into the frequency domain, compares them to expected signals, and identifies faults by analyzing amplitude across frequencies, allowing for the determination of specific component issues and enabling proactive replacement or repair.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic speed sensors are used to measure the speed of rotating components, then control and fault detection capabilities are improved, but the ability to predict component wear and failure remains inadequate

Engineering Contradiction:
Improvespeed measurement precisionVSAvoidfailure prediction capability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transforms the sensor signal from the time domain to the frequency domain using Fast Fourier Transform (FFT). This dimensional transformation allows the system to analyze vibration frequencies that correspond to specific component conditions (bearing defects, gear issues, shaft problems) rather than just measuring rotational speed. The frequency domain analysis reveals patterns and characteristics that are not visible in the time domain signal, enabling predictive capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system changes the parameter being analyzed from simple speed (time domain) to frequency content (frequency domain). By examining the spectral composition of the sensor signal, the system can identify specific frequency signatures associated with different types of component degradation and failure modes, transforming a basic measurement tool into a diagnostic and predictive system.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If signal analysis is performed to detect faults in rotating components, then fault detection capability is improved, but the complexity of the monitoring system increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoidsignal processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical disassembly and physical inspection methods with electronic signal processing. Instead of mechanically accessing and examining components, the system uses FFT algorithms to extract diagnostic information from the electrical signal already captured by the magnetic sensor. This substitution of mechanical inspection with computational analysis reduces physical complexity while enhancing diagnostic capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system creates a frequency domain representation (spectrum) as a copy or transformation of the original time domain signal. This spectral copy contains the same information in a different format that is easier to analyze for fault detection. The FFT process generates a frequency spectrum that serves as an analytical copy, allowing diagnosis without altering the physical system.

Inventive Principle:
Principle #26Copying

3Loss of time

If continuous monitoring of rotating components is implemented, then maintenance timing is optimized, but the cost and complexity of the monitoring system increases

Engineering Contradiction:
Improvemaintenance timing optimizationVSAvoidmonitoring system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The system enables the rotating components to essentially monitor themselves through the magnetic speed sensor that captures vibrations and operational characteristics during normal operation. The FFT analysis processes this self-generated data to detect degradation trends, allowing the components to indicate their own health status without requiring external inspection systems or disassembly.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary analysis of the sensor signal by transforming it to the frequency domain and identifying potential issues before they lead to actual component failure. By detecting early signs of wear, misalignment, or other problems through frequency analysis, the system enables proactive maintenance scheduling before critical failures occur, optimizing maintenance timing.

Inventive Principle:
Principle #10Preliminary action

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

This approach effectively predicts component failures before they occur, enabling timely replacement and reducing the risk of engine start failures, flight disruptions, and extending maintenance intervals by monitoring internal vibrations without disassembly.

Implementation Method 1

magnetic speed sensors to measure the speed of rotating components

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

An air turbine starter (ATS) is an example of such machinery... using magnetic speed sensors

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3715821B1Prognostic monitoring and failure detection of rotating components
Publication Date: 2025.01.01 HAMILTON SUNDSTRAND CORP
  • EP3715821B1 patent drawingFigure 1~3
  • EP3715821B1 patent drawingFigure 4
  • EP3715821B1 patent drawingFigure 5~7

AI summary

A method of monitoring a rotating component includes gathering an electrical signal from a sensor arranged adjacent a rotating component of an assembly. The electrical signal is transformed from a time domain into a frequency domain. The electrical signal is compared to an expected signal.