There is an 670 kw electro motor, which had a 1.4 micro meter vibration on end bearing and 4.0 micro meter on?

Question

the pump drive end, after that we had seen a sharp raise in vibration on the pump DE, to 11; we decided to check the bearings, but after that the values changed to 10.0 and 12.5 for the electro motor end bearings. spectrum showed a peak in 1xRPM and a very very small tooth on 6000rpm. oil analysis showed small particles in housing bearing oil sample.

is it true to say that there is unbalance in Rotor? if yes where it came from, it wasn't so since last week.

Answer 1

*Small particles in oil ? It should not be there.

Particle may damage the surface of the rolling elements.

What is the temperature trend?

Is there any sharp rise?

Is there any play[axial/radial] in pump shaft or motor shaft?

What are the alignment reading?

If you have a vibration meter capable of filtering the frequency, then filter out the component of vibration[1*rpm,2*rpm,3*rpm]

Take the reading in the following sequence:

horizontal,verticle and axial.Its a international standard.

Take ratio of all reading .There is a thumb rule that can be useful in deciding vibration factor.

Check the following:

Levelling of the pump and motor.

Alignment of the motor-pump.

Tightness of the fasteners,see the condition of the baseframe.

Check the condition of foundation.

While taking reading,be sure that it can be taken below the centre line of the bearing housing especially H & A components.

I am writing all above as it is not clear from the question.

There is a less possibility of unbalancing of rotor .

There may be effect of bearings.

If there is a hot application,then you have to think about hot-alignment.

Please give feed back.

Please go through the following link,it may be helpful:

http://www.mcnallyinstitute.com/02-html/...