Question about different vibration analyzers

[dmcnew]

So this is a very basic question for someone who knows very little about vibration analysis. I work at a utility and we are looking at a few different consultants to conduct a vibration analysis on our two GE Frame 5 combustion turbines.

One consultant plans to use a CSI 2120 and another consultant has a Bently Nevada system. It is my understanding that these are two very different systems, but what I don't understand is if there is any signifcant difference in the quality of the results we are going to get?

Basically, is there something the Bently analyzer can tell me that the CSI 2120 can't?

 

[drmuh]

The reading (raw) data must be the same for both systems if you have same initial settings (resolution etc.). Post processing capabilities may differ depending on the capabilities of the systems.

http://www.novosim.com

Product Development Services (cad/cae/test)
Medical Device R&D

 

[dmcnew]

Is there anyone here who is familiar with both systems? I just want to make sure that the CSI 2120 will be sufficient for our needs, so maybe anyone who has used the CSI 2120 on a combustion turbine? My chief technician seems to think that the CSI 2120 won't be able to pinpoint problems like the BN system can, but I'm not entirely convinced of that.

 

[GregLocock]

A competent test engineer would be able to do the entire job with an oscilloscope and a filter box, the choice of analyser is not going to define the ultimate quality of the job.

You probably need to define whinch BN anlayser he's using, FWIW I see more CSI gear around than BN.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[dmcnew]

So it is with most testing. That is the scary part of going with a large testing company, usually never know who you are going to get.

Thanks for the help both of you.

 

[DLite30]

The CSI 2120 is essentially a more portable version (i.e. handheld) than the Bently setup, and results, given that the same transducers are used, the results will be the same.

The one big difference between the two is that the Bently setup will be able to aquire data for many different points simultaneously, which is helpful for when you do a waterfall plot over decreasing or increasing speed range, which probably isn't the case, since your machine probably operates at a single speed.

So, it depends on what you're really looking for.

If you just want to start trending the condition of the unit over time, the CSI system will be good. If you think you have a bearing issue and just want to verify that vibration levels are high, the CSI will work.

But more importantly than the aquisistion system is the ability to interpret the data. I would suggest that for your analysis consultant, that you use someone that is familiar with turbine engines, unless you already someone who know to look for. Because anyone can stick a transducer on anything and tell you what the vibration levels are, but can't differentiate between synchrons speed vibration, vane pass frequency, gear mesh noise, or oil-whirl, etc...

I can probably suggest a couple for you to contact.

 

[MachineryWatch]

It really depends on which Bently equipment is being used. If he is using Adre then he will be able to collect data simultaneously from multiple sensors, as described by DLiteE30. If he is using the Snapshot data collector from Bently he may have less capability than the CSI 2120. Also, if the CSI 2120 is a single channel version instead of the 2 channel version he would not be able to look at orbits from the prox probes. There really are a lot more pertinent questions to ask, as has been pointed out by others before my response.

http://www.machinerywatch.com

 

[Strong]

I use a CSI 2120 2-channel analyzer and a ZonicBook 8-channel analyer (similar to Bently Adre capability) because each has its value depending on the situation. I would not judge a consultant solely by his/her tools, but rather by experience, success, and report/communication skills. Some folks labeled "consultants" are only data collectors, while a few others actually understand the machines, the types of faults to expect, and solve problems. What do you want: a data collector person or a machinery expert?

Walt

 

[thoenig2]

GTI Spindle Technology has developed a full spectrum 2 chanel vibration analyser on Apple's ne iPad.