The present application relates to the technical field of fan bearing fault diagnosis, in particular to a fan bearing fault online detection method and
system, adopting a weighted combination envelope spectrum technology, quantifying the correlation of fault characteristics and
resonance frequency bands through two-dimensional spectrum coherence, combining the
frequency domain signal-to-
noise ratio to adaptively assign weights, aggregating and enhancing the fault information of
multiple resonance frequency bands, effectively offsetting the attenuation effect in the
signal transmission process, solving the problem of
signal attenuation
distortion caused by magnetic attraction installation through the
machine shell under the limitation of fan structure size. The
order tracking and
constant angle increment sampling technology is introduced, the corresponding relationship between the vibration signal and the bearing rotation angle is established, the
time domain signal is converted into the angle domain signal, the fault characteristic frequency and the rotating speed are decoupled, the theoretical fault frequency of the inner ring, the outer ring, the roller and other components is accurately matched with the detection result, the detection adaptability under variable working conditions is greatly improved, compared with the
fixed frequency domain analysis of the traditional acceleration
envelope method, the misjudgment caused by
frequency offset is effectively avoided.