**6. Appendix (A): Bearing rotational frequencies**

In general, the bearing inner race is attached to a shaft and therefore has the same rotational frequency as the shaft (*Fs*) while the outer race can be assumed stationary, since it is generally locked in place by an external casing (i.e. it has a constant rotational frequency of zero). The bearing rotational frequencies can be obtained as follows (Figure 1-7):
