BPFO – Ball pass frequency Outer ring
The spectrum is characterized by the presence of harmonic peaks of the disturbance frequency of the outer ring (between 8 and 10 harmonic multiples of the BPFO).
E.g. for the SKF 22228 bearing, the frequencies are calculated for 1500 revolutions:
![SKF-bearing-fault-fgrequency](https://vibroguard.cz/wp-content/uploads/2023/05/SKF-bearing-fault-fgrequency.jpg)
So in the spectrum we would see 1x BPFO peak at 205.3Hz and harmonics 2x, 3x, …
![Bearing_fault_BPFO](https://vibroguard.cz/wp-content/uploads/2024/04/Bearing_fault_BPFO.png)
Examples of outer ring damage: