Bearing Housing Vibration 2

[ghoshtathagata2000]

We are currently executing a project which has centrifugal pumps, centrifugal blowers, induction motors among other equipments applying Bently Neveda's bearing housing vibration monitoring.

On this subject, GE has two kinds of such instruments to offer. One is the accelerometer which measures the acceleration of the bearing housing (m/s2 or in/s2) and the other instrument which directly gives the vibration velocity ( mm/s or in/s)of the bearing housing.

From the point of view of equipment condition monitoring, can somebody please elaborate which of the two kinds of instruments is recommended for such machineries.

 

[Tmoose]

Is the question about the better sensor choice, or the better vibration units for monitoring?

I suspect the Bently system could process either sensor type to display velocity. Velocity is often considered more useful to judge machine condition, as generally speaking it gives approximately equal importance to frequencies related to lower frequency stuff like unbalance and misalignment, AND troubles that are likely to cause vibration at higher frequencies like ball and roller bearing condition.

I view overall readings (with carefully selected frequency range) as useful, but really at best a trigger for more detailed vibration measurements

 

[JJPellin]

Our standard would call for accelerometers for this sort of application. I think velometers have made some impressive advancements in the past few years. But, in my experience, accelerometers are more durable and provide good data accuracy over the typical frequency ranges for rotating machinery.

I would use accelerometers taking measurements in (in/s2) and have the B-N system process the signal to display and trend velocity in (in/s). As Tmoose suggests, velocity provides a good general indication of typical machine problems.


Johnny Pellin