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Noknroll

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Reply with quote  #1 
While analysing some data I came across a set of fault frequencies that didnt look right for the machine in question.
When I drilled down in the tree structure, to my surprise, the machine had no fault frequencies assigned. Can anyone explain or seen this before?
fault freq.png

Vibe-Rater

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Reply with quote  #2 
H Nok, I've not seen it before. FWIW A thing I would check is go into plot data and see if anything pops up when displaying fault freqs alongside a full screen plot.  Probably not I'd say. Not sure what that achieves but to get to the bottom of it I would check.  Did you close fdown mhm and reopen? I know that when you have a module open - make a change - and alt+tab to another open module that other module does not update until close  and reopen. Cheers
Noknroll

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Reply with quote  #3 
G,day Vibe
Do you mean like this? see below
I tried, but closing and re-opening MHM did nothing 
do any Emmerson people visit here?
Edit: I just noticed G's RMS ?
All good, VA Tab, which I pretty much use exclusively is in Pk 
plot d.png
Vibe-Rater

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Reply with quote  #4 
Yes Nok, I do mean that.  Why some people enter shaft speed as 1 (as a fault freq in the list alongside) is a mystery to me. I would have thought that ISO minus 20 exam would have ensured that 1x is 1x and is what everyone should know. But hey. You did not set this up I know.  From time to time DM from CSI Knoxville visits here but only if pushed to do so. He goes back a LONG way with CSI and I met him here a few times at the old MSC reliability weeks. I agree I use acceleration in Peak, not RMS and velocity in rms to match the iso standards.  Met up with current Emerson people at shin dig last night in Melbourne city for free beers. That was for all things Emerson, not just vibration. So did not know many people.  They will have a 2 dayer in next year but don't know where yet. See how it goes. rgds
Danny Harvey

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Reply with quote  #5 
Nok,

I'm not sure I understand your question but this might help.

There are two sources for fault frequencies.

RBMWizard applies some if that is used to build the machine (and it looks like this was). They look like the ones that are shown on the right side of the spectrum you posted. (Maybe your question is why they don't display on the spectrum?)

And then there are the fault frequencies in Dbase that you are showing in the first pic.

To change it you can open Plotdata and select Globals in the upper right hand corner.

Pick the Analysis Option tab.

Go down to the Fault Frequency Options for Source.

You can select Point Fault Frequency (Dbase), Equipment configuration (Wiz) or Combine all sources.

Maybe yours is set for Equipment Configuration only.

Good luck and hope this helps.





Noknroll

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Reply with quote  #6 
Hi Danny
My question was......how come I can run fault frequencies over my plots in VA tab and plot data but as can be seen in the OP there are no fault frequencies assigned to that point?
I'll run through your suggested actions when i get to the office and report back

Vibe, at the shindig for beers, is there any other reason to attend such an event
Noknroll

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Reply with quote  #7 
Hi Danny
I checked my set up and it was "Point fault frequency" I changed it to  "combine all sources"
but made no difference
Maybe this screenshot shows more clearly what my issue is, as you can see the plot has fault frequencies on it but the database point setup has no faults assigned???
ff2.png

OLi

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Reply with quote  #8 
I have a very faint memory that if none was set it defaulted to something but may be wrong, it was long time ago.
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Danny Harvey

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Reply with quote  #9 
Nok,

Since there are no fault frequencies assigned in DBase, it will display only the fault frequencies that are contained in any configuration that was done in RBMWizard.

I would suggest two things.

1. Open RBMWizard and drill down to the machine.  It should show you if there is a configuration assigned.  From there you can look at the configuration and it will show the details of bearings, rotor bars, coupling method, etc. that were entered in RBMWizard at some point.  This is probably where the fault frequencies that are being displayed are coming from.

If the machine was copied from another, it likely was copied with all that information included.

2. The other thing you can do is to add some fault frequencies to the MP in Dbase.  You can add up to 7 to each point and I use it mostly for bearings that are discovered after the database is built using the Wiz, but you can use it for just about anything you want to track.  You can put 3 bearings in at the Wiz and 7 more at the MP if you need 10. If you do that and have it set to combine all sources, you should be able to see the existing ones from Wiz plus the new ones from DBase. (I'd give you specific steps but my server isn't serving right now.)

That's why I like to use the Wizard, especially for building gearboxes.  If you have the geartooth and bearing info, all you have to do is enter it into the Wiz and it does all the fault frequencies automatically. But it doesn't do a good job assigning AP and AL sets unless it's changes with the new stuff.
Noknroll

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Reply with quote  #10 
Thanks Danny
I'll go through your instructions when the weekend is over and back to work
This database is nearly 20 years old and has had quite a few different custodians over the years. I personally dont use the wizard but the original creator or one of the subsequent custodians probably did
Rang

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Reply with quote  #11 
+1 for Danny's suggestion. From VA tab, right click on the plot, setup options, select fault freq source as req'd. It seems the FF's have been created in the wizard (god forbid).

EDIT: It's also possible that the points haven't been assigned in the wizard for analysis. You'll have to go back into the Wizard and re-configure them. The KBA NK-1100-0519 explains how to do this.
Noknroll

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Reply with quote  #12 
well i got lost in the wizard, never used it before, couldn't find anything about fault frequencies anyway. But in VA tab if I select measurement point as the source, as expected no fault frequencies appeared on spectrum, so obviously they (fault freq's) were configured in the wizard. 
Rang I dont have access to the knowledge base, or at least I dont think I do.
I'll just put some FF's in to the measurement point as suggested by Danny
Once again I've been schooled by the forum members, thanks
Danny Harvey

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Reply with quote  #13 
Nok,

You won't find anything about fault frequencies in Wizard because it makes them without telling you.

To change the configuration or delete it entirely you can do this.  (This is from v 5.42.)

1. Open RMBWizard.
     A. Click Open Existing Database
     B. Select and open the datbase

2. Expand the hierarchy to the machine level. It will show a screen with Eq. Name, Equipment ID and any configuration assigned to the machine.

3. You can click Edit to change the name, id or base speed and whether it is variable or constant speed.

4. You can click Configure to see the actual configuration.  This is where it gets the info to make the fault frequencies it doesn't tell you about.

     A. There should be some icons of a motor, coupling and pump.  You can double click on any of those and it will start a series of screens where you supply the information and it generates the MP's and assigns AP and AL sets.  (This is the part it doesn't do very well.  I always replace the AP and AL sets with ones of my own creation.) You can correct any speeds, coupling methods (couplings are considered anything that connects the two machines including belts and chains), bearing ID's here.  There's a could of places that you can get into trouble here.  I'd be careful with the Regenerate MP's selection in Configuration.  I have really screwed things up with that one before. Once so bad that I had to start all over on a line shaft driven paper machine dryer.

    B. You can then go to the top tool bar and select Configuration-Edit Measurement Points.  This will give you two tabs at the bottom, Vibration and Assign. Vibration is a table of all the points, speeds, positions, orientations, etc. Assign is where you assign the MP's to whatever shaft they are on. (This is what one of our colleagues was alluding to.)  This is how it links the speeds in belt drives, gearboxes, etc.

    C. After you make any changes, you can shut that down. It will ask you if you want to save the changes. Remember that if you clicked Regenerate MP's, it might make all new measurement points right now and you will have to delete them each individually.

5. After doing that, you will need to go back to the main screen for RBMWizard and click on the hammer icon.  It will ask you if you are sure that you want to build a new database based on the changes you have made and caution you that they will be permanent changes.  Being fully confidant that you are not going to absolutely wreck a 20 year old database, you will click yes and hope for the best.

Or, you could just select the database information for your fault frequencies and pretend that the old ones are not there.  

The larger point is that RBMWizard is a really good tool for building a database but if you are trying to change one, you really need to be careful with it. It can be done, but it has to be done in exactly the right fashion or you will wind up with a mess.
Noknroll

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Reply with quote  #14 
Danny
Thanks for taking the time to explain all that, its much appreciated.
I think I'm going to take the soft option in your last sentence and pretend the old ones dont exist.
I might be a dare devil at motorcycle riding but I aint mess'n with no database like that what your talk'n bout
Danny Harvey

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Reply with quote  #15 
It might be a good idea to make a copy of the database that you can practice on. RBMWizard is especially good if you do a lot of complex variable speed drive trains. You just need to know the things it does a poor job of and the ways you can wreck it.
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