Method of diagnosis of varying load mechanical failure

Abstract

The invention relates to a fault diagnose method for variable load machine. The fault of the variable load machine is not easy to diagnose automatically, because the vibration value is compared with the alarm threshold set in advance in the traditional diagnose method, but the load is positively correlated to the vibration value; as a result, misinformation and missing report occurs if the traditional method is applied to the variable load machine. The method of the fault diagnose method is that the vibration signal of important parts of the machine and the power signal of the machine are collected simultaneously; then the vibration signal and the power signal are disposed with statistical regression analysis in order to elicit regression equation; the alarm threshold corresponding to the instant power of the machine is worked out according to the equation and the instant power of the machine; then the vibration and the alarm threshold are compared; alarm is given if the vibration surpasses the threshold; the alarm threshold varies with the power the machine. The fault diagnose method for variable load machine is mainly applied to the development and design of the diagnosis system of variable machines (such as the variable flow rate pump used in industry, variable power motor, and wind power generator).

Description

technical field [0001] Mechanical Fault Diagnosis Background technique [0002] The mechanical vibration analysis and diagnosis method is to use the sensor to collect the vibration signal of the key parts of the machine, and perform pattern matching according to the digital characteristics of the signal, so as to identify the type of mechanical failure. Such methods include: time domain analysis, frequency domain analysis, delay domain analysis, etc. The theoretical basis of these diagnostic methods is the processing of stationary signals, such as Fourier transform. Some methods developed in recent years, such as multi-sensor resonance demodulation fault detection technology (Patent No. 90105568), time-delay correlation demodulation method (Patent No. 03114649), etc., are actually derivative methods of the above methods, and their basis is still stable signal processing. [0003] Practice has proved that using the above-mentioned vibration analysis method to diagnose vari...

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Problems solved by technology

At this time, if the above method is still used for diagnosis, it is easy to draw wrong conclusions (it is easy to miss diagnosis when the load is small, and it is easy to misdiagnose when the load is heavy), or even no conclusion (the spectrum of non-stationary signals is usually very complicated, and the law is difficult to find)

Other non-stationary signal processing methods that can extract fault information, such as Wigner-Ville time-frequency distribution, short-time Fourier transform, wavelet transform, wavelet packet analysis, etc., involve very deep theoretical foundations and complex calculations, so they are not easy to be applied

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