If Ultrasonic detectors "detect" 30 kHz how can they produce spectrum showing low frequency signals that are usually associated with roller/ball bearing faults?

Will someone please post an example of an Ultrasonic spectrum showing a bearing problem?

Terry O

Terry,

Here is a link to some spectra:
http://www.sdtnorthamerica.com/PDFs/Integrating%20Ultra...n%20Technologies.pdf

I use ultrasound (SDT 150) along with vibration (CSI 2120-2). I generally don't bother with taking a ultrasound spectrum because of the hassle of using both instruments together.

Walt

Interesting article.

Why not just use vibration analysis?

Terry O

Terry,

Because if vibraiton analysis was the only and best tool for bearings, then your oriqinal question would not have been asked.

Walt

Again if the UT is set at 30 kHz, does the "frequency setting" have anything to do with the Spectrum Readings?
The SDT 150 is preset to 38.4 kHz as is the SDT 170. Although, the SDT 170 does have a frequency tuner that will allow you to go from 15.1 kHz up to 190. kHz
The UE has a tuner that will allow you to go from 20kHz to 100kHz. It is ususally set at 30kHz for bearings.
Appartently both of these companies are going to try and redefine what role the airborne ultrasound is to play in diagnosing bearings in the future.
Some vibration experts, while they are dedicated vibration guru's have respect for waveform analysis and what can be seen by the Ultrasound receiver. Again, I haven't heard nor do I expect anyone will say this technology will be used instead of vibration. But, for those companies who have not invested in, nor want the learning curve associated with vib may use the ultrasound to retrieve bearing data.
Comments Please? PLUS is you have any case histories on such please share with us....