Rotating machinery frequency-doubled fault diagnosis method based on three-dimensional holographic difference spectrum

Abstract

The invention relates to a rotating machinery frequency-doubled fault diagnosis method based on a three-dimensional holographic difference spectrum. The method comprises the following steps of: firstly, determining a measuring point with the most sensitive fault response on a unit shaft system, analyzing the main excitation frequency and amplitude variation trend of the measuring point by utilizing a frequency spectrum waterfall chart or a characteristic trend chart, and judging whether the fault type is a frequency-doubled fault or not by combining a rule; then calculating a double-frequencythree-dimensional holographic spectrum matrix of the shaft system in a normal state and a plurality of fault states, and constructing a double-frequency three-dimensional holographic differential spectrum matrix corresponding to the fault states on the basis; and finally, drawing a frequency-doubled three-dimensional holographic differential spectrogram of the shaft system in a plurality of faultstates to obtain a pure fault frequency-doubled ellipse of the whole shaft system in a fault development process and change characteristics of characteristics of the pure fault frequency-doubled ellipse, determining a fault source position by combining the characteristics, and carrying out qualitative diagnosis on the frequency-doubled fault. According to the method, the difference of the fault response signs is represented from time and space dimensions, and key diagnosis information is provided for accurately distinguishing rotor cracks and misalignment faults.

Description

technical field [0001] The invention belongs to the technical field of mechanical fault diagnosis, and in particular relates to a double-frequency fault diagnosis method for rotating machinery based on a three-dimensional holographic difference spectrum. Background technique [0002] Among all the causes of double-frequency faults in rotating machinery, rotor cracks and misalignment are the most common and difficult to distinguish and detect effectively. There are two main reasons: On the one hand, these two faults have extremely Similar spectrum characteristics, traditional analysis tools such as spectrograms and spectrograms are difficult to provide differentiated fault information; on the other hand, they often occur during unit operation, and the two have similar development processes The amplitude and phase of power frequency, double frequency and other vibration characteristic values ​​change with time are also very similar. Conventional detection methods and means, su...

AI Technical Summary

Problems solved by technology

For example, two-dimensional holographic spectrum and full spectrum both emphasize the use of double-frequency trajectory shape at a single measurement surface at a single moment to extract differentiated information, and often face the problem that the root cause of the fault cannot be diagnosed due to similar double-frequency trajectory characteristics question

In addition, some methods require specific operating conditions when identifying double frequency faults, which greatly limits their applications. Vibration information, and most of the actual units are running at the working speed. Once the vibration is abnormal, it is often necessary for the diagnostic engineer to give accurate diagnostic opinions without stopping the equipment, so that the equipment manager can make the correct diagnosis. maintenance decision

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