A client of ours had recurring issues with a rotary lobe vacuum blower. Initial collections of vibration data showed the machine in a stable condition with no notable issues. As the year went on, the machine’s condition steadily worsened.

With many machines, like pumps and fans, historical trending of overall vibration amplitudes can be very effective. With other machines, such as compressors or vacuum blowers, their overall vibration levels are more heavily influenced by the process of the system. The needs of the system will influence the load on a vacuum blower, causing fluctuation in overall vibration levels.  Additionally, the condition of the filter can have great affect on overall vibration as well. These factors add significant variation to measurements of overall vibration, so it is vital to prioritize frequency analysis when monitoring the condition of a vacuum blower.

In August, the motor on the vacuum blower was replaced, but the newly installed motor didn’t seem to fix the existing issues. Before we were able to collect another data set on the newly replaced motor, our client’s vendor for the vacuum blower came on site and gave the recommendation that the blower needed to be replaced. Shortly thereafter, we collected a data set on the new motor. The data from this collection showed bearing defect frequencies were present, pointing to an issue with the inner race of the bearing. Significant increases in vibration amplitudes were noted at the drive motor, from a range of 6-8 G to 18 G. One of our vibration analysts recommended rebuilding or replacing the motor.

Days after our collection, the motor was replaced. Another data set was taken in September, and the results were dramatic. No bearing defect frequencies were present, and overall vibration levels went from 18 G to less than 1 G. Our client avoided costly downtime from a potential failure thanks to timely repairs recommended by our trained vibration analysts.