I'm seeing this data on a suction press roll. 40"D running 400rpm at 450pli. Drive end bearing 23260CAK. It looks like 2x ball spin occuring at 1/2 rpm. Am I right? The data is Time Waveform with a gSE filter.

pr5t.xls (48 Kb, 74 downloads)

I've narrowed it down a bit. The frequency is FTF modulating 2x BSF. This is a fairly large bearing. Any thoughts on what could produce this signal?

In general, the pattern you describe suggests a defect on a ball.

2*BSF due to defect hitting twice per revolution (once on inner race and once on outer race).

The FTF modulation corresponds to the speed the ball moves around within the bearing (it moves with the cage). The modulation is either due to the defective ball moving closer and farther away from transducer... or else into and out of load zone.

quote:

The data is Time Waveform with a gSE filter.

What does the normal velocity spectrum and accel waveform look like?

Here is the "normal" data.

pr5ta.xls (93 Kb, 40 downloads)

Is there harmonics of BPFO showing or what is this in the spectrum?

The 10 and 20kcpm are gearmesh and harmonics with running speed sidebands.