BPFI Frequency

[rota2]

Hello everyone.
Does BPFI frequencies first occur at a frequency less than 1x running speed.

 

[GregLocock]

If you mean what I think you mean then no, unless you have fewer than 1 but more than zero, blades.

if that makes no sense, well you need to explain what you are talking about.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[electricpete]

Ball Pass Frequency of the inner race for conrad beairng is approximately 0.6 * number of rolling elements times the running speed.

So for a 8-ball bearing it would be somewhere just less than 5 times turning speed. (I'm assuming outer race is stationary and inner race rotating). There are formulas to calculate it exactly if you know ball diameter, race diameters, and contact angles. Or you can typically look it up in most vib programs if you know bearing part number and manfuacturer

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[GregLocock]

Ah, not to be confused with blade pass frequency in a fan, obviously!

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Rob45]

Nor to be confused with the Beer Pouring Frequency...