Amplitude frequency spectrum used for mechanical rotor single cross section shaft vibration analysis

Abstract

The invention relates to an amplitude spectrum used for mechanical rotor single-section shaft vibration analysis; the production of the amplitude spectrum comprises the following steps: (1), importing the synchronously acquired displacement signal sequences x and y of two vertical directions of a section of a rotating shaft; (2), processing fast discrete Fourier transformation on the two signal sequences, respectively; (3), evaluating the respective Fourier series according to the two signal discrete Fourier transformation results; (4), in the two obtained Fourier series, synthesizing the sine wave harmonic component of the x-signal with the sine wave harmonic component of the y-signal under each frequency so as to obtain an axis orbit ellipse, also known as Lissajous figure; (5), calculating the size of the semi-major axis of the synthesized ellipse under each frequency, namely, the size of the shaft amplitude on the section under each frequency; (6), and taking the frequency or the order as the horizontal axis, and taking the shaft amplitude as the longitudinal axis to map out the amplitude spectrum. Each shaft amplitude stands for the actual size of the shaft vibration of the section under the corresponding frequency and is not affected by the mounting direction of the sensor.

Description

technical field [0001] The invention relates to an amplitude frequency spectrum used for analyzing the axial vibration of a single section of a mechanical rotor. [0002] For large rotating machines with sliding bearings as rotor supports, such as large motors and centrifugal compressors, the most basic tool for analyzing and evaluating their operating status is the frequency spectrum of the rotor shaft vibration displacement signal, because the rotor shaft vibration displacement The signal spectrum can decompose the shaft vibration signal by frequency—decompose it into a group of shaft vibration components corresponding to different frequencies and display it to the user. [0003] Usually, at a supporting section of a rotating machine, two vibration displacement sensors perpendicular to each other pointing to the center of the rotating shaft, called X sensors and Y sensors, are installed on the stator to obtain the vibration displacement signal of the rotor on the section, se...

AI Technical Summary

Problems solved by technology

The disadvantage of this amplitude-spectrum method is that if the installation orientation of two mutually perpendicular sensors on the section changes (such as by figure 2 becomes image 3 ), even if the rotor running state remains unchanged, the amplitude spectrum of the monitored x signal and y signal will show a difference, which is not convenient to establish the relationship between the amplitude spectrum characteristics and the machine state, and it is also not convenient to compare two sensors with different installation orientations. state of the same machine; in addition, this amplitude spectrum, because it is the spectrum of a single-directional displacement signal, as attached Figure 4 , attached Figure 5 , attached Image 6 , attached Figure 7 As shown, therefore, any value on the spectrogram cannot reflect the maximum value of the axial vibration component of the section at its frequency (that is, the axial amplitude value)

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