Rotary Machine Current Sideband Detection for Loss Diagnosis
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Solution Overview
Problem
Existing methods for diagnosing abnormalities in rotary machines and driven machines do not effectively detect increases in mechanical and copper losses based on driving current analysis.
Innovation Solution
A diagnostic device that acquires and processes driving current data to detect sidebands and determine frequency differences, allowing for the identification of abnormalities in mechanical and copper losses by analyzing the slip and sideband frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current analysis methods are used to detect abnormalities in rotary machines, then general abnormality detection is possible, but detection of mechanical loss and copper loss increases is not achieved
Solution Approach 1:
The patent segments the current spectrum into multiple frequency components, specifically identifying sidebands around the carrier frequency. By dividing the spectrum analysis into distinct frequency regions (carrier frequency and sideband frequencies), the method can separately detect different types of abnormalities including mechanical loss and copper loss increases that were previously undetectable by conventional single-frequency analysis methods.
Solution Approach 2:
The patent transitions from analyzing only the carrier frequency (one-dimensional approach) to analyzing both carrier frequency and sideband frequencies (multi-dimensional approach). This dimensional expansion in frequency space enables the detection of additional abnormality types by capturing information distributed across multiple frequency components rather than relying on a single frequency point.
2Reliability
If existing diagnostic methods focus on sideband frequency analysis, then certain abnormalities can be detected, but mechanical loss and copper loss increases remain undetected
Solution Approach 1:
The patent introduces sideband frequencies as intermediary indicators that mediate between the driving current and the underlying mechanical/copper losses. By analyzing the relationship between carrier frequency and sideband frequencies, the method indirectly detects mechanical loss and copper loss increases through their characteristic signatures in the frequency spectrum, making these previously undetectable parameters measurable.
Solution Approach 2:
The patent monitors changes in frequency parameters (sideband frequencies and their intensities) as indicators of mechanical loss and copper loss increases. By tracking how these frequency parameters change under different operating conditions and abnormality states, the method transforms the difficult-to-measure loss parameters into detectable frequency domain characteristics.
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 the detection of abnormal increases in mechanical and copper losses in rotary machines and driven machines, providing a method to determine the presence of failures and potential issues before they cause significant damage.
Implementation Method 1
a current from a sensor that measures a driving current of the rotary machine
Implementation Method 2
perform sampling on the driving current thus acquired
Implementation Method 3
convert time-range data having been subjected to the sampling into a frequency range
Implementation Method 4
set, in the frequency range, the driving current as a carrier wave and detect, as a sideband, a portion of a spectrum appearing on each side of the carrier wave having been amplitude-modulated
Data Source
AI summary
A rotary machine diagnostic device has a current acquisition unit that acquires current from a sensor, which measures the driving current of a rotary machine driving a machine to be driven; a sampling unit that performs sampling of the acquired driving current; a frequency range conversion unit that converts data concerning the time range subjected to sampling into a frequency range; a sideband detection unit that sets the driving current as a carrier wave in the frequency range, and detects, as a sideband, the spectrum appearing on each side of the carrier wave subjected to amplitude modulation; and an abnormality detection unit that detects whether or not there are abnormalities in the rotary machine and the machine to be driven on the basis of the difference in frequency between the sideband frequency detected by the sideband detection unit and the frequency of the carrier wave.