below are the data for the industrial motor coupled to a centrifugal pump

motor speed 1487RPM

bearing are white metal bearings both NDE and DE

power is 970 kW

please assist me with the analysis attached 

there is a funny noise from the motor when running 


Photos (5)
Original Post


Hi, below comment is for clarification;

1. Does the funny noise occur during start-up?

2. Does your attached spectrum is taken during your so called funny noise?

3. Does the funny noise didn't disappear during operation?

4. Whats is the recorded enveloping acceleration for motor drive side and non-drive side? also the timewaveform? any significance changes in trend history?

For me, when i encountered abnormal noise like a sound pressure noise at motor, i do phase analysis for motor base bolt, for me to check if there is a soft foot or looseness which affect the airgap of motor resulting the abnormal noise. also, abnormal noise will generate if there is a clearance a outerace of bearing and housing, but the noise will not last until the bearing meet the thermal expansion, also when the bearing is cocked, you can confirm it through phase reading. if bearing noise through metal to metal contact, you can check it in the TWF and you can perform greasing, anyhow, with your limited data and problem state, all this i can say. 

Don't depend on velocity spectrum for bearing fault, use envelop acceleration, TWF and correlate them both.


Dear  Tsietsi ,

Is that motor has a fan along with internal air circulation type ? , if so it might be due to air circulation or air turbulence issue with in the Fan casing .

Did taken Fan reading while decoupled ?  , is there any sound like this ?

Please check these parameters and share your motor image .


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Photos (1)

With reference to the attached spectrums

1. In one of the image RPM is showing as 985. What is this spectrum is there any speed reduction in machine train?

2. What type of a pump is it? no of vanes, no of diffuser, between bearings or cantilever?

3. As mentioned about the funny noise from motor, as I could read all the spectrums corresponds to pump side. Kindly clarify whether these spectrums are of pump or motor. If these are of pumps kindly attach some spectrum of motor to identify the funny sound.

4. Kindly attach some time waveform data for further analysis.





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