Gearbox between a steam turbine and generator.

Good afternoon everyone,

I am back in search of guidance and wisdom, ok I need help.

My senior is out for a week and I am left to my own experience.

I took readings on a turbo generator yesterday that had me concerned last month with high axial vibration on the outboard sleeve bearing of the input shaft.

These readings are from a magnet mounted accelerometer which is not optimal for a sleeve bearing application but is used for condition monitoring.

Last month the readings came out to 11G's axially and this month they dropped to a bit over 6.

This month the horizontal has climbed to 12.6 G's and decreased axially.

The first question from anyone was did you reverse the sequence of readings, the answer is no.

All the readings are taken with a Emerson 2140 and the inspector feature

stated " Exceptional condition exist, no recognizable faults found"

Plain English for your on your own.

I have wave forms and spectrums I could place here but being that this is a sleeve bearing rather then a rolling element am I comparing apples to oranges?

 

 

Original Post
Sarah M posted:

I see that the system wont let me add anything

That may be because you are a relatively new member, not uncommon.

I'd be surprised that it is a double reduction, "3 shaft" as you call it.  5652 RPM down to 1800 is readily handled by a single reduction, 2 shaft arrangement.  One never knows for sure however.  Can you post the nameplate data here as text?  The most important info would be manufacturer, model number, serial number, and speeds.

Can you identify the dominant frequencies and harmonics/sidebands and indicate whether multiple of turbine or generator speed?

Were the two data sets taken at the same load and preferably not too close to startup time, if machine had been down (load and temperature can affect levels)?

Was the accelerometer placement at exact same location (especially for high frequencies)?

Walt

Good morning everyone,

I was out at customers since I posted for help.

The data points are the same from month to month and taken during the afternoon, so the turbo generator has been operating constantly for a few days by the time I get to it.

Having been told we have all the equipment listed on file I did not take pictures of any data plates.

Come to find out the data on the equipment was lost during computer system upgrade and never repopulated.

I still cant attaché a file to this. I will copy to jump drive ant try from my own computer.

 

Sarah, following Walt's instructions should work fine and virtually all file formats are acceptable.  There is a max file size of 100 MB.  You do have to place your cursor into the area for adding text before the option "Add Attachments" appears in the lower corner.  Once you click on "Add Attachments" you should get a screen allowing you to "point" to the desired file.  Once you point to the file and upload the status should change to "Success", then click on Finished.  Make sure you wait for the "Success" status because transmit time is a function of the speed on both ends of the connection.

If you still don't have any success, you might check with your IT people.

 

I did do repeatability checks as well as live monitor around that end of the shaft.

As for load I cant get the same loads at every interval since this generator provided all the power for the plant.

I will start taking note of the power draw next time there.

As I said I only have a bit over 12 months doing this vibration analysis.

Sarah M posted:

 

As I said I only have a bit over 12 months doing this vibration analysis.

Don't worry about having only "12 months doing this."  Both William (Bill) Foiles and I had that amount of experience once, admittedly it was long ago in another century!    

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