End Winding Vibration Diagnostics for Electrical Machine Faults
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Solution Overview
Problem
Existing methods for fault condition diagnostics in electrical machines, particularly in the active shaft region, are inadequate as they fail to independently assess end winding vibrations, leading to potential irreparable damage and unscheduled downtime due to resonance phenomena caused by manufacturing inaccuracies, operational changes, and mechanical ageing.
Innovation Solution
A method utilizing end winding vibration measurements, involving frequency transformation and comparison with reference spectra to determine fault conditions, including the placement of sensors along the axial length and circumference of the end winding to differentiate between various fault types such as dynamic and static eccentricity, and inter-turn short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometers are installed at both ends of the stator to monitor vibration levels, then vibration monitoring capability is improved, but device complexity and measurement precision are worsened due to inability to independently assess end winding vibrations
Solution Approach 1:
The patent uses the stator core as an intermediary structure to mount sensors that measure end winding vibrations. The stator core serves as a mediator between the end windings and the measurement system, allowing vibration assessment without direct attachment to the end winding structure itself. This resolves the contradiction by enabling precise measurement while simplifying installation through the intermediary stator core structure.
2Reliability
If sensors are placed to monitor end winding vibrations, then fault detection capability is improved, but difficulty of detecting and measuring is worsened due to resonance phenomena and vibration sources from multiple locations
Solution Approach 1:
The patent segments the vibration analysis by measuring vibrations at specific locations on the stator core that correspond to different end winding regions. By dividing the measurement into discrete locations (first and second locations on the stator core), the system can differentiate between vibrations originating from different sources, resolving the difficulty of source identification while maintaining high fault detection capability.
Solution Approach 2:
The system uses feedback from vibration measurements at multiple stator core locations to continuously assess end winding vibration levels and compare them against thresholds. This feedback mechanism enables real-time fault detection and differentiation by analyzing the relationship between vibrations at different locations, resolving the measurement difficulty through systematic data interpretation.
3Reliability
If vibration monitoring is implemented to prevent damage, then reliability is improved, but loss of time increases due to unscheduled downtime and maintenance requirements
Solution Approach 1:
The patent implements preliminary monitoring of end winding vibrations to detect early signs of resonance and potential damage before they occur. By continuously measuring vibrations and comparing them against predetermined thresholds, the system enables preventive maintenance scheduling based on actual condition assessment, thereby preventing unscheduled downtime while optimizing maintenance timing to minimize operational disruption.
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 enables effective fault diagnostics in the active shaft region, reducing maintenance downtime and preventing damage by accurately identifying fault conditions through improved sensitivity and unambiguous diagnostics.
Implementation Method 1
obtaining a vibration measurement from an end winding sensor arranged on an end winding of the stator of the electrical machine, and configured to measure vibrations of the end winding
Implementation Method 2
End winding vibration becomes severe when the excitation forces acting on it, reach a resonance phenomenon with the natural frequencies of the end winding structure
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
The present disclosure relates to a method of determining fault conditions in an electrical machine by means of end winding vibration measurements. The method comprises obtaining (S1) a vibration measurement from an end winding sensor arranged on an end winding of the electrical machine, and configured to measure vibrations of the end winding, frequency transforming (S2) the vibration measurements to obtain a frequency spectrum of the vibration measurement, comparing (S3) the frequency spectrrum with reference frequency spectra, and determining (S4) whether a fault condition is present in an active shaft region of the electrical machine based on the comparison between the frequency spectrum and the reference frequency spectra.