Anyone explain?

[realize]

Using Machine analyst from SkF detecting substansial 300hz with amplitude of 1,4.
Any chance this comes from a ABB DCS 500 rectifier?
And why?

 

[electricpete]

Assuming your are in 60-hz land, I'd say it's very plausible. In a three-phase full bridge rectifier, there are 6 diode and each has one turn conducting per cycle. The dc output of the rectifier has 6 peaks per 60-hz cycle. Even when filtered there may be some 6*LF ripple remaining on the output dc and it may pass through to signals derived from that dc.

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[realize]

Yes im in 60 hz -land
Thank you for your response, was wondering why I have an increse in amplitude at 300hz aswell as 6-900hz.
Still ripple? And does it matter for the equitment?

 

[realize]

Im so sorry, im in 50 hz land off course.
And as you know its in 6times FL it occours.
But my question remains as to the increase of amplitude in this range.