Problem is unbalance couple or motor issues?

this motor drive the boiler feed water pump not blower. I do not think much about alignment issue. The reason is SCL both end of motor is normal. Of course, having a misalignment between pump and motor but with flexible coupling and as my experience, the misalignment seems not to make vibration like this (my think could be wrong).

From the spectrum i see that there are 50Hz with both side band 48.75Hz and 51.25Hz and the frequency is exactly line frequency. So, i confuse if there is dynamic eccentricity issue due to rotor bar, lamination...but i do not have experience on motor. Therefore, i hope to hear some ideal from electricity engineer here.

The sideband are associated with the frequency resolution.  I don't think the SCL on the DE bearing are acceptable. There is an out of phase behaviour across the motor.  I would not think this motor is operating under the influence of its second mode. 

Thanks for your comment. I will consider for alignment check again. We did alignment check, bearing check, run out check 5 days ago and no abnormal is recorded with bearing, couplings except for misalignment in vertical plane. We corrected and the result as i posted here

At present, the motor is brought for refurbished shaft journal due to electrical damage (pitting on shaft journal). We measured the shaft journal diameter and saw that the shaft journal diameter at both side of motor is not the same with difference of 0.08mm. Is it make the difference like the sideband here.

I understand, the motor was overhauled, during which the shafts were metal sprayed or was the bearing white metal replaced?

Either way, the bearings would have to be refitted. Either by mounting the bearing halves on the shaft or placing the lower half in the motor base and lowering the armature into the bearings.

My question relates to whether the bearings and journals are now aligned or "cocked" (angular error) on the shaft or in the housing. An angular error may give some strange hydrodynamic fluid effects and consequently change the vibration signals.

Do your temperature probes read oil bath, oil flow or bearing temp? Are they normal?

Thank Jim,

all temperature is in acceptance. Now, we still on refurbishing process. And of course, we will do blue check for bearing seat and also to check the quality of refurbishment.

i still wait to see what different from the past when the shaft journal was equal. 

I think that it seem to be mistake here. The problem existed before the machine was shutdown for inspection and then refurbishment.

So, everything have not finished. now, the refurbishment is still under process, so, I still wait to see  the result when the rotor re-install into motor.

When you hook up your probes, do a loop test to make certain that the probes are routed back to the proper channels.  In other words, make certain that the physical probe XE 8253Y goes to the XE 8253Y rack channel, XE 8253X goes to the XE 8253X rack channel, etc.  Verify for both ends of the motor on re-installation.

Add Reply

×
×
×
×