Does any body here has experience with high axial vibration on motor installed in vibrating screen (type Techno vibrazioni)
Greetings Mr. AYMAN GAMAL,
If you have taken on Motor DE/NDE bearings and Axial vibration high, you can expect rotor Shaft bend. Normally in over hung fans and blowers, Horizontal motors when bearings overheated shaft bend occurs and Axial vibration will be more than radial vibration.
Please send the spectrum with motor 1x identified to see the pattern.
In what direction are the vibromotors installed relative this motor?
To what extent the high axial vibration? How much is the level of vibration from horizontal, vertical vibration and axial?.
the vibration at MNDS is H=5 mm/s V=3.5 mm/s A=16 mm/s
at MDS H=4.9 mm/s V=4.4 mm/s A=15.9 mm/s
the spectrum has peak at 1X only at all direction.
I see, you cab do phase analysis for confirmation it it is bent shaft. Did you try to run and take reading on motor solo run condition?
No i didn't make solo run for the motor but this problem back to commissioning phase and from that time we are suffering from this problem and i cant identify where the problem , is it alignment issue or something in the design .
You should verify first on solo run condition for you to identify if it is in motor or any, then if the vibration still manifest then try to do phase analysis. You can uncouple the cardan shaft and take a run on solo.
If the vibration drop on solo run, you have no problem on bent shaft, also you can do also do impact test on axial direction.
I recently have an issue the same as your and during analysis, i have structural resonance due to weld crack on VS frame.
Have you confirmed that the universal joint jackshaft from the motor to the screen is installed correctly and is not in a bind or the axial slide is not bottoming out in the axial direction? What is the angle of the jackshaft from the motor to the screen?
Mr. AYMAN GAMAL ,
Check Cardon shaft angular offset to the Motor coupling and Vibrator screen side / Cardon shaft condition first .
The truth is high axial vibration on electric motor is really not common;
In this case based on the data u have provided, the high axial vibration is both on the drive end and non drive end; it certainly means the problem maybe inherent in the motor or maybe caused by high axial load from the screen...What I would advice you to do is run the motor on solo first, to eliminate any axial load condition from screen, if it persists on solo run, den you have to check the run out of the shaft, basically you should have a maximum of 1 thou, although u can check run-out tolerance on the service manual, if it's above the tolerance it's obvious the shaft is bent...but if it's okay, you will be left with checking the condition of the thrust bearings, or even the bearings if they are cocked, motors used for screens are fitted with bearings with high axial capacity...
On the other case if the axial vibration vanish on solo run, then you will have to inspect the condition of the coupling, screen structure and load condition...least I forgot, how about the amperage on the motor is it normal?
Any update on this issue?
next week i will check some steps, i will post any update if found
Check splines expansion joint in drive shaft for seizure, wear? If there are such.
please.. check vibration alson at the structure, this look like low stiffness in axial direction..
I have seen a lot of similar cases in our steel industry.
High 1x or 2x axial vibrations can have many reasons. Follow the following steps 1 by 1.
1. Run motor in solo condition. If high axial vibration is still there, bearing should be out of clearance that makes it slide axially.
2. If on solo, axial vibration is dropped, there is a strong indication of axial misalignment.
(in solo condition, for perfect machine your vibration readings at all locations should be closed to 0).
3. If all two above steps are done and high axial vibration is still there, go for phase analysis and confirm bent shaft.
SYED HUZAIFA AHMED, you were spot on, on the clearance issue, but reason i doubt excess clearance was due to the low radial vibration, most especially on the vertical axis, but anyway, since the bearings are to be opened it will be very okay to confirm the clearance
here is report from the vendor showing the actual situation of the vibrating screens, i believe that the problem in the screens and transmitted to the motor via cardan shaft according to inspection report
please revise the report and feed me back
check vibration behavior at sereval representative points of structure, and you can see the biggest vibration point in axial direcction, because you are taking reading in axial point of motor, but remenber that the motor is held down to the structure and if the structure move.