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MarkL

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Reply with quote  #1 
Hi Folks, I am having an issue finding a supplier of the following, the model shown I cannot find on the vendor site, just wondering would the proc probe gurus be able to point me in direction of an alternative?
4dec74a0-2608-4c22-a56b-b79b0663c75f.jpg 

OLi

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It was new to me but I try to avoid probes like that... You should find it here:
https://www.sensor-messtechnik.de/produkt-kategorie/vibrationsaufnehmer/vibrationssensoren/beruehrungslose-wegsensoren/

Vielen Glueck

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MarkL

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Reply with quote  #3 
Hi Oli, it's on a squeeze oil-bearing on a Piller MVR fan.
Why do you say you try to avoid? mind me asking?
I hadn't seen them either only familiar with Bentley by name. 
When I click that link its taking me back to the same site I was on but not the sensor in question, maybe the link is broken.

Are these units power supplies?( I know nothing about prox probes)[6_PRO_DD1008_750px-324x324]

Is the box in my picture only a housing?
OLi

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Reply with quote  #4 
Picture seems to be a CTC Proximitor, the box whatever brand have the electronics, oscillator "driver" that drives the probe and the probe is just a cable with defined capacitance and by that length with a defined coil in the end.
I don't have anything about this brand I just try to avoid eddy probes as principle, specific it annoy me when people think they can measure the thickness of the oilfilm that is infinite thin and way smaller than the accuracy of the measurement system even in the best case. In some best case with comp you may calculate how much shaft movement is compared to physical clearance in the bearing but only if you know what you are doing.
So a fan with a squeeze bearing yikes what wrong did it do to get that?

Picture looks like this:
https://www.ctconline.com/proximity_probes_pro_line.aspx

I can source that and many others.

I think you need to ask them at

https://www.sensor-messtechnik.de/kontakt/

it may be a obsolete and they swapped to CTC supplier and they can advice a replacement as it is their logo on the thing.


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MarkL

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Reply with quote  #5 


The MVR fans are using squeeze oil-bearing to overcome the critical and limitations of a rolling element on its own...so I was told. It is a common thing on Piller MVR units. They use an skf Housing and then put the squeeze oil set up in the housing, I had never heard of them before this. 


Previous post I made on same machine https://www.machineryanalysis.org/post/squeeze-oil-damper-bearing-anyone-monitoring-them-10446189


[squeeze-oil-bearing]
OLi

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Reply with quote  #6 

Well, in my world squeeze is a designers last resort when having bad "luck" during design ending up with a oil lubed bearing with to low bearing load and getting bearing instability. I only seen it in turbines IRL and luckily rarely even so and some small cooling fans but hey were in the hundreds all the same.
Problem you get is bearing instability. There may be different levels of squeeze bearings and it is a jungle including not circular that sometimes are called "lemon" I think and tandem designs all
to avoid some kind of resonance or other problems within a speed range for a device and to my surprise found in slightly larger electric motors for example that was not expected so you are never safe.
I see you only have 1 eddy probe transducer per bearing so you can't do the orbit analysis thingy. I guess if you only need to detect a problem with bearing instability you can measure with anything including walking by since the vibrations may be "significant".

I can not really see how these bearings would have to low load unless they are very over designed and that has a simple solution, just cut down the with of the bearing :-) that is how it was solved in your average ventilated leather seat fan in your SAAB Griffon (car).
Normally the reason antifriction bearings can't be used are the speed but since they I think also are stiffer they may give another resonance picture. There are however many reasons for things to end up as they are so you never know. 
I would always have a accelerometer on the gbx if that's what is peeking out in the left side, that is suggested even by API and maybe one on the bearing near the fan to monitor the unbalance but that is just me.
What can happen with time is that the bearings get worn, clearance increase and you get back the instability (if that is a problem) and that is the worst in my imagination you need to look out for the next 30 years hopefully.


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Walt Strong

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Reply with quote  #7 
My interpretation is that the VDC100--- is a custom holder for a proximity probe. The Messtechnik wed site shows the CTC product line, so I would expect that standard CTC proximity probes would be used.

Walt
OLi

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Reply with quote  #8 
So if you look up the other end of the probe cable and look at the electronics box it maybe have CTC sticker with all info needed.
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MarkL

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Reply with quote  #9 
Olov,
The pic I used was from the web, there is no gearbox on this, the motor is Siemens 900kw doing 3500-4500rpm in operation.


I have emailed the OEM Olov and will see what they come back with.
Walt,
Good point, I imagine its just a badge engineering exercise. I haven't seen the module in the panel for this. 

Thanks for your help guys.
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