Static Eccentricity Fault Detection in PSH Induction Motors
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Solution Overview
Problem
Conventional methods fail to detect static eccentricity faults in principle slot harmonic (PSH-type) induction motors due to PSH signals being generated under both healthy and faulty conditions, leading to undetected failures and significant financial losses.
Innovation Solution
The use of a second-order harmonic in air gap permeance to generate a static eccentricity fault signature current signal, which is filtered and compared to a pre-computed lookup table to quantify the fault severity, enabling accurate detection through motor current signature analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional motor current signature analysis methods are used, then detection capability is improved, but PSH-type induction motors cannot be detected because PSH signals are generated under both healthy and faulty conditions
Solution Approach 1:
The patent segments the PSH signal into multiple frequency components and identifies that the second harmonic component specifically contains static eccentricity fault information. By focusing on this segmented frequency component rather than the overall PSH signal, the method achieves reliable detection for PSH-type motors.
Solution Approach 2:
The patent transitions from analyzing the amplitude dimension of the fundamental PSH signal to analyzing the frequency dimension by examining the second harmonic component. This dimensional shift reveals fault information that is invisible in the conventional analysis approach.
2Productivity
If PSH signal amplitude is used for fault detection, then conventional detection methods work for most motors, but PSH-type motors show no significant amplitude dependency on eccentricity levels
Solution Approach 1:
The patent changes the detection parameter from fundamental PSH signal amplitude to second harmonic component characteristics. This parameter transformation reveals the hidden relationship between static eccentricity and signal characteristics in PSH-type motors, enabling precise measurement.
3Ease of manufacture
If conventional detection methods are applied to PSH-type motors, then manufacturing process continues without interruption, but undetected faults lead to motor failures and financial losses
Solution Approach 1:
The patent enables preliminary detection of static eccentricity faults during the manufacturing process using the second harmonic analysis method. By detecting faults before motors are deployed, the system prevents future failures while maintaining manufacturing workflow.
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 allows for the reliable and quantitative detection of static eccentricity faults in PSH-type induction motors, reducing maintenance costs and preventing failures by identifying faults early in the manufacturing process.
Implementation Method 1
The use of a second-order harmonic in air gap permeance to generate a static eccentricity fault signature current signal
Data Source
AI summary
A system for controlling an operation of an induction motor (IM). A controller processor detects a spectrum of a current signal from received sensor data using a module. Obtain a number of rotor bars and a number of pole pairs of the IM to identify a principle slot harmonics (PSH) type IM from stored IM data. Use the PSH-type IM to identify a static eccentricity (SE) fault signature signal located at a secondary PSH frequency of the PSH-type IM. Determine a level of signal strength in the spectrum of the current signal at a location of the secondary PSH frequency, and compare to a SE fault table database to obtain a SE fault level of the PSH-type IM. Compare the SE fault level to a database to obtain a SE fault threshold, and if the SE fault level is outside the SE threshold, generate an interrupt command to the controller.