Full spectrum Plot / Spectrum of Orbit

[ssingh1]

Dear Friends,

I would like to plot the Full Spectrum of Generator Shaft. I found some information about the  same which I am reproducing below :

Full spectrum
The full spectrum is an additional diagnostic tool and is also called the spectrum of an
orbit. It shows the same information as an  orbit but in a different format. It helps to
determine the degree of ellipticity (or flattening) associated with the various machinery
conditions along with the precessional direction for all the frequency components present.
To obtain the full spectrum, the orthogonal X and Y transducer signals are fed into the
direct and quadrature parts of the FFT input. The positive and negative vibration
components for each frequency are obtained. Positive is defined to be the forward
precession and the negative component as the reverse precession. These components
yield the following ellipticity and precessional information for a given orbit of any
particular frequency (1× or 2× or …):

•  The sum of two components, forward and  reverse, is the length of the orbit
major axis.
•  The difference between the two components is the length of the orbit minor
axis.
•  The larger of the two components, positive or negative, determines the
direction of precession that is forward or reverse.

One of the possible applications of full spectrum is analysis of the rotor runout caused by mechanical, electrical or magnetic irregularities. Depending on the periodicity of such irregularities observed by the X–Y proximity probes, different combinations of forward  and reverse components are observed. The method forms the basis for  many useful machinery diagnostics.

The full spectrum (just like the normal FFT) can be obtained in a steady-state analysis (a single FFT or waterfall) and even in transient analysis, which would then be called the full spectrum cascade (Figure attached).

I would like to know if anyone has the idea as to how to get this plot?

I am familiar with Labview and normal analysis tools available like FFT etc., but I need help in performing this Advanced Analysis in Labview.

 Regards

Shourya

[ssingh1]

Any thoughts please 🙂

[preston_johnson · Accepted solution]

Thanks for your posting and the jpg you provided.  Of course it is possible to create a full spectrum in LabVIEW.  We had done this a couple of years back, I had to get the VIs updated to LabVIEW 8.6.

Please let us know how these work for you.

[ssingh1]

Dear Preston Johnson,

Thanks for remembering to post and for your valuable time given for reply.

Actually I am currently having LabVIEW 8.2.1 with Sound And Vibration Toolkit 5 installed so I shall be grateful if you can please post VIs for these versions also.

With regards

Shourya

[preston_johnson]

Try these

[ssingh1]

Dear Preston Johnson,

Thanks for your prompt reply.

Now I am able to open the VIs, however i am getting some errors in executing them, which I am attaching with this post. I hope you get some clues from the error lists and help me in sorting them out.I am sorry for bothering you so much 🙂

With regards

Shourya

Message Edited by ssingh1 on 09-06-2009 11:32 AM

[ssingh1]

Dear Preston Johnson,

I had a chance to test the VI's given by you on a a computer having Labview 8.6 with Sound and Vibration Suite 7 installed on it. I would like to inform that the VI's worked perfectly well.

Thanks again for your reply to my query.

With regards

Shourya

[preston_johnson]

Thank you for the feedback, I am sorry I had not replied to the error report. 

[jenz]

Hi Preston,

I'm using SVMS 2010 but I can't find the OAT Full Spectrum.vi in LabVIEW. Where can I find it?

Regards Jenz

[preston_johnson]

The Full Spectrum VI is the same as provided for LabVIEW 8.6

Please let us know what questions you have.