Vibration Analysis

[daveydoo14]

How often do you guys perform vibration analysis? and how is it done? Pertaining to Centrifugal Chillers.

[henpeck]

Years ago, I would once to twice a year along with oil samples. It varied from customer to customer, and their maintenance practices and or what was pushed or sold in a contract. Some customers would get kick backs if it was used on all their equipment at the time??? The main thing is the importance of a piece of equipment. Its done by using micro-log to gather vibration spectrum data to be analyzed by specialist. Taking two radial and a axial reading as close to bearing as possible.

[motoguy128]

I believe we're doing it quarterly on most of our centrifugals.

[drivewizard]

More often is better, if you have a customer that is willing to pay.
Ideally every 500 to 1000 run hours for Centrif.
I used to take the data only once a year, because that is what most customers were willing to pay for.
Plus our cooling season up here is only about 3-4 weeks long.!

If you have a machine that exceeds alarm levels you might want to check more often.

[Tech Rob]

It seems like most are done on an annual basis around here. Bi-annual if the customer specs it. I think quarterly sounds a bit excessive, unless you own the equipment and have the ability to interpret the data for yourself.

Some customers opt only for oil analysis as a more cost-effective i.e. cheap solution to detecting bearing faults. When I quote work for these customers, I always try to sell a vibration analysis with the job. My opinion is that vibe analysis is a good tool that can be applied to almost anything in the plant.

[Healey Nut]

How often do you guys perform vibration analysis? and how is it done? Pertaining to Centrifugal Chillers.

Nothing but a bunch of BS designed to make money through some kind of witchcraft .
Get er at full load and if you can stand a quarter on er without it falling over shes good to go .

[jayguy]

... Get er at full load and if you can stand a quarter on er without it falling over shes good to go .

what if you can't? what if i glued the quarter standing up-right...ok then?

[drivewizard]

Nothing but a bunch of BS designed to make money through some kind of witchcraft .
Get er at full load and if you can stand a quarter on er without it falling over shes good to go .

It's Black Magic with a little smoke and mirrors thrown in for good measure!

Check out this site: http://maintenanceforums.com/eve/for...m/f/3751089011

read a few posts by electricpete and you will get a good understanding of the complexity and knowledge involved.
When I read some of the posts on this vibe forum it makes me feel like an absolute moron.

[Healey Nut]

what if you can't? what if i glued the quarter standing up-right...ok then?

Chewing gum , choose your colour ..
But seriously , your going to listen to some bearing science geek with qualifications in bearing nerdery who knows sweet S!!t about centravacs and refrigeration tell you you have bad bearings based on some electronic wizadry ??
The quarter trick is possible(I use a canadian dollar) Ive done it to show customers after teardowns etc . I once placed a quarter on the outboard bearing end of a CVHE heat recovery chiller that runs 24/7 and it was still there 6 weeks later standing up no glue no bubble gum , only reason it fell over was a power bump cycled the chiller off .

[jayguy]

...But seriously , your going to listen to some bearing science geek with qualifications in bearing nerdery who knows sweet S!!t about centravacs and refrigeration tell you you have bad bearings based on some electronic wizadry ?? ...

Yes, I would listen because I am one. Last year I passed my Level III test. Now I am studying for my Level IV which will probably take about 3-4 years to get ready for it. I love it the most because I do know sweet S!!t about what I am working on.

I am interested in finding all of the faults (I can find some in your machines too! ). Finding the faults has nothing to do with finding blame...not all faults require repair. I have measured bearing faults that were there at start up and didn't develop into any concern for 11 years! But when the fault did start to grow in size, we were able to quote the replacement of the bearing and fix some leaks that had been annoying for several years but didn't warrant repair by themselves. Cheaper for everyone, scheduled when it was convienent for the customer and our office and NOT when the chiller wanted it fixed...which would have been in the middle of summer by the time you could hear it.

All bearings have faults...you can't afford to buy a bearing without any faults...perhaps NASA could. The difference is in knowing when the fault is going to develop into a problem that needs to be dealt with. Hopefully, your Vibration Analyst can predict the fault 3-4 months in advance (or more, but that can be difficult in some situations). This will give you time to get multiple quotes, get all parts in using regular shipping methods (rather than next day air), find out some of the parts were shipped wrong, send them back, get the right ones and all before you show up...no headaches, no delays.

Vibration Analysis is only required if you want to know (and predict in advance) what is going on inside the machine without cutting it open. It is no more important or less important than any other tool in your tool bag. I would imagine that EKG's, CAT scans, blood pressure measurements and rectal thermometers were all once thought to be hocus-pocus...but they too give you an inside peek at how YOU are doing without cutting you open!

[Healey Nut]

[QUOTE=jayguy;12798461]Yes, I would listen because I am one. Last year I passed my Level III test. Now I am studying for my Level IV which will probably take about 3-4 years to get ready for it. I love it the most because I do know sweet S!!t about what I am working on.

I am interested in finding all of the faults (I can find some in your machines too! ). Finding the faults has nothing to do with finding blame...not all faults require repair.

Im still not buying it ...bunch of smoke filled coffee house crap if you ask me.
Guess im just to old school , I'll stick with my long electrical screwdriver and my good ears and oil samples to to tell when its time for a bearing job .cheers:

[Healey Nut]

[QUOTE=jayguy;12798461]Yes, I would listen because I am one. Last year I passed my Level III test. Now I am studying for my Level IV which will probably take about 3-4 years to get ready for it. I love it the most because I do know sweet S!!t about what I am working on.

I am interested in finding all of the faults (I can find some in your machines too! ). Finding the faults has nothing to do with finding blame...not all faults require repair.
All bearings have faults...you can't afford to buy a bearing without any faults...perhaps NASA could.

Ok so heres another angle, you say all bearings have faults , not all faults need repair .

Mr customer has 6 chillers , all oil samples good , all chillers running smooth no excessive noise , all purring like kittens (they must be Tranes ) You show up and do your wizadry and and hubble bubble toil and trouble , eye of newt toe of dog stuff . Tell him a whole buch of stuff in a bearing nerd science langauge he doent comprehend .
Top and bottom of it is you tell him everythings faulty from a nerdy bearing science guys point of view and all the faults ????? are fine no need to worry .

So Mr customer has a written report telling him theres lots of Faults ??? no need to worry and a big fat bill to pay...... for what ????
He could have saved the 10Gs he just spent to tell him he has faults that dont need fixing (isnt that an oxymoron) on something way more useful and productive in his facility .

All my emails have a signature that says ...."If it aint broke dont fix it "
and no one with a diploma in bearing science nerdery is going to convince me otherwise ,, no dissrespect to you Jay but Im not buying it period .

[txhvac]

Say! How about CVHE-SB-18 must have come from the Witchcraft and Wizardry divison over at LaCrosse. Hey Graham you forgot the old oil return line amp method along with the trick quarter.