Title Fault Diagnosis Method of Gearbox Multifeature Fusion Based on Quadratic Filter and QPSO-KELM

Table 2

Relevant frequencies of the gearbox.

Rotating frequency (r·s^−1)			Meshing frequency (Hz)		Fault feature frequency of bearing (Hz)
fr1	fr2	fr3	fm1	fm2	fBPFO	fBPFI	fBSF
20	10	4	820	371.67	36.588	54.965	23.787