×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

alarm level / limits standard ?

alarm level / limits standard ?

alarm level / limits standard ?

(OP)
Can anyone tell me if there is a beginning standard of alarm limits or level criteria on bearings up to 75.5xrpm prior to making my own limits after further trending.What is a good starting point.
Will peakvue be the same or slightly different?

RE: alarm level / limits standard ?

The Vibration Institute uses the following velocity limits
in in/sec
                                   rms            peak
Acceptance of new equip      <0.8            <0.16
unrestricted operation       <0.12           <0.24
surveillance                0.12-0.28      0.24-0.7
Shutdown immediately        >0.28            >0.7

RE: alarm level / limits standard ?

Are you asking for general machine condition alarms based on measurements made on the bearings, or alarms that apply specifically to the condition of the bearings?  They really are 2 different things.  The Vibration Institute guidelines are certainly valid for the general machine condition assessment (as are standards from other sources such as ISO and even standards established by and recommended by some private firms).  The condition of rolling element bearings is quite another thing.  The bearing condition determination is made not so much on overall amplitudes, but rather on the development of specific "bearing-related" frequencies in the spectrum.  Generally speaking we see more and more of these frequencies in the spectrum and more indications of modulation (sidebands) as the bearing wear continues to worsen.  The amplitudes may remain quite small in spite of severe bearing condition deterioration.  This is especially true with relatively slow speed (<600 RPM) shafts.  The total energy from these low amplitude bearing frequencies may have little actual impact on the overall vibration level.

PeakVUE is an excellent tool, when properly configured, but it's value is in it's ability to make the bearing-related frequencies more visible in the spectrum while diminishing the high-amplitude frequencies that normally dominate the velocity spectrum.  PeakVUE amplitudes have no discernable relationship to the velocity amplitudes measured because it is such a heavily "massaged" or processed signal.

The PeakVUE amplitudes are very dependent on things like the transmission path to the sensor from the source of the energy and the filters and other parameters chosen by the analyst for the measurement.

This is not the definitive answer you may have been looking for, but I hope it is helpful, none-the-less.

Skip Hartman  

http://www.machinerywatch.com

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources