Vibration analysis or Ear Defenders and a long handled screwdriver?

[Grizzly]

Hi Guys!
Many sites I go to now advocate the use of Vibration Analysis as a form of preventative maintenance.
Which is a useful tool if used correctly, I am assuming the use of this is taught in the college's nowadays?
However is it just me?

Because sometimes when having been told that the outside contractors have carried out the Vibration analysis.
I ask what load was the compressor at when the test was carried out?
Invariably there is no reply!

Anyway I don't have access to said useful tool, but have access to a Long Handled Screwdriver and a set of "Cans!"
Which I used only the other day to pinpoint what I concluded was the beginning of excessive wear on a Grasso pack (Booster)with a large Oil Pump.
And I wondered if this historic practice was still taught in the college's
Grizzly

[RANGER1]

Grizzly,
I have found VA to be hit & miss, also expensive for a preventative tool.
You need the most experienced people to use it effectively.
They need base data from new, all bearing type, numbers & usually at the same slide valve capacity as you mention.
A lot of screws noisy unloaded, but at 100% sound sweet.
On one job, a Bitzer screw we were very concerned about, compressor seized during the test!
Obviously our concerns were on the money, but to late.
Bitzer apparently changed thrust design as it was suspect.

The analysis also cannot tell slide valve wear in a screw, which is common in our neck of the woods.
I have the old stethoscope from auto tool shop.
To me it's a tool to be used when you run out of ideas, or want to pinpoint something.
Example new or near new equipment which is still under our warranty or very premature issues.

A stethoscope or screw driver is still relevant to me, as cheap & easy.
If you use it on motor bearings definitely works.

A lot lot will disagree, but each to their own.

[RANGER1]

Hi Guys!
Many sites I go to now advocate the use of Vibration Analysis as a form of preventative maintenance.
Which is a useful tool if used correctly, I am assuming the use of this is taught in the college's nowadays?
However is it just me?

Because sometimes when having been told that the outside contractors have carried out the Vibration analysis.
I ask what load was the compressor at when the test was carried out?
Invariably there is no reply!

Anyway I don't have access to said useful tool, but have access to a Long Handled Screwdriver and a set of "Cans!"
Which I used only the other day to pinpoint what I concluded was the beginning of excessive wear on a Grasso pack (Booster)with a large Oil Pump.
And I wondered if this historic practice was still taught in the college's
Grizzly

Grizzly,
I know screw driver method, what's with the cans?
I thought it was a in the field test rule of thumb, not really taught in college, but I see you do it, now I do it type of thing.
Also with the Grasso, what had wear, the oil pump?
Could it be to much oil injection?
A lot of Grasso's no oil filter after pump (assume we are talking screw compressor), but which is a bit of bad luck.
Grasso also recommend thrust check every 5000hrs (yeh right), although very easy to do.

[Grizzly]

Hi Ranger.
Sorry for the delay, as I was banned from my computer as my Grand daughter was on a sleep over.
You younger guys have this all to come!
Anyway with regard to the use of a set of "Cans" read Amplivox ear defenders. The type that slip over your ears like ear muffs.

I have found that whilst wearing them I can hear noises which are not normally as pronounced.
So lifting them on and off an ear, when near a suspect sound. Can help pinpoint potential issues.
So I use them as a rudimentary tool just as "We" do with a screwdriver!

The Oil pump is no big secret as it's on a pack which was built in 1996 and still going. It is whining etc. now.
So I have asked Grasso what spares and support is still available as a precaution. (With the customers Blessing)
Credit to them it would appear to still be supported.
My original post is really to ask if others still use the methods we have talked about.
And thanks for the interesting detailed replies!
Grizzly

[monkey spanners]

Nothing i work on is big enough to bother with vibration analysis, but i do have a mechanics stethoscope for finding bad bearings etc or listening for leaks in milk tank evaporators. Also use the screwdriver technique or thin tube for similar tests.