Table 1 Characteristic frequencies of each bearing component
From: FPGA implementation of an improved envelope detection approach for bearing fault diagnosis
Component frequencies | Fundamental frequency formulae \([{\varvec{H}}{\varvec{z}}]\) |
|---|---|
Ball-pass frequency at the inner ring (\(BPFI\)) | \({f}_{i}=\left(\frac{N}{2}\right)\cdot F\cdot \left(1+\left(\frac{B}{P}\right)\mathit{cos}\alpha \right)\) |
Ball-pass frequency at the outer ring (\(BPFO\)) | \({f}_{o}=\left(\frac{N}{2}\right)\cdot F\cdot \left(1-\left(\frac{B}{P}\right)\cdot \mathit{cos}\alpha \right)\) |
Ball-spin frequency (\(BSF\)) | \({f}_{b}=\left(\frac{P}{B}\right)\cdot \left(\frac{F}{2}\right)\cdot \left(1-{\left(\left(\frac{B}{P}\right)\cdot \mathit{cos}\alpha \right)}^{2}\right)\) |
Fundamental train frequency (\({\varvec{F}}{\varvec{T}}{\varvec{F}}\)) | \({\varvec{f}}=\left(\frac{{\varvec{F}}}{2}\right)\cdot \left(1-\left(\frac{{\varvec{B}}}{{\varvec{P}}}\right)\cdot {\varvec{cos}}\boldsymbol{\alpha }\right)\) |