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Danny Harvey

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Does anyone know what kind of sensor Dodge puts on their Sleeve-Oil RTL Pillow Block bearing?
John from PA

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Reply with quote  #2 
https://www.google.com/search?safe=active&client=safari&channel=ipad_bm&ei=EwPCXObhOOu3ggfao53gBQ&q=dodge+sleeve+oil+bearings+vibration+transducer&oq=dodge+sleeve+oil+bearings+vibration+transducer&gs_l=mobile-gws-wiz-serp.3...1750.9287..10420...0.0..0.173.1970.16j5......0....1.........0i71j0i22i30j33i22i29i30j33i299j33i160.PUikcnD2jus#imgrc=ayYGC9Pxt1AIjM:

On at least the one photo, it looks like an ABB sensor and at least the one shown may be wireless.

http://ucc.colorado.edu/baldor-reliance/sleevoil_access.pdf On page 6 shows the vibration detector mounting kit.
MarkL

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Reply with quote  #3 
Hi Danny, Those are the new ABB sensors they are touting for pillow blocks, they are part of a new sensor suit they are offering. 

OLi

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Reply with quote  #4 
Those I have seen is Bluetooth.
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Danny Harvey

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Reply with quote  #5 
Thanks for the info.  I had found the maintenance manual John posted but it doesn't have any real info. (Interestingly enough, these bearings are only 2 15/16" which is not covered in that manual.  I'm not sure why they went with sleeve bearings here. The rotor weight is only 1507 lb. I don't encounter many fans this small with sleeve bearings.) I'm guessing that they are getting an overall from something like 0-60,000 cpm. It may be measuring running speed because there is a tachometer attached. It looks more like a zero-speed switch than a tach though.  It has a multi-magnet disc attached to the end of the shaft. 

This is on two brand new medium sized center hung FD fans (400 hp, 1790 rpm) and I am being asked by the construction manager to fix the vibration. The manufacturer has suggested a trim balance after stating that the rotors are balanced to a G2.5 grade. I'm not certain that anyone knows what made the alarms trip or not trip.  If they are just measuring the overall, it might not be balance. 

All I can find out is that someone or something senses that these fans vibrate. They may have exceeded the alarm of .3 ips peak and the shut down of .39 ips peak or they may not have.  

If I knew it was running speed amplitude, I would suspect a resonance in something and while a trim balance will help remove the exciting force for right now, what happens down the road when an exciting force returns?

I'm going to encourage that we determine the source and address it appropriately.  If it's a resonance near operating speed, putting a fine balance on it may get them past start-up testing but it sounds like a possibility of a long future of frequent trim balancing or shut down point altering. 



Walt Strong

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Reply with quote  #6 
Here is a link to ABB Sensor:
https://new.abb.com/mechanical-power-transmission/mounted-bearings/smart-sensor-for-mounted-bearings

Walt
Walt Strong

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Reply with quote  #7 
Danny,

The ABB sensor appears to be more suited to ball/roller bearings than sleeve bearings. The frequency range is 1-Hz to 1.6-kHz, and it detects overall RMS level. You need to make your own measurements before guessing the possible cause!

Walt
Danny Harvey

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Reply with quote  #8 
It's a Wilcoxen velocity probe.  I'm still not sure what they are getting out of it but I think it's an overall. What range, I don't know. Whatever it is, it shuts them down at .39 ips peak. I measured .374 at running speed and .393 overall on one of the fans so I suppose one of us is slightly off.  My client asked me why it hadn't shut down which I explained but his glassy-eyed stare told me that he wasn't really into the nuances of vibration sensors and just wants his fan to stop shutting itself down.

Cross channel phase analysis showed close to a 180 degree shift (hor) across the coupling on every single fan. I was given alignment reports that show good alignments but had the plant guy check one out today after I left and found it was a little out in vertical and angular but I wouldn't think enough to cause much vibration. They are supposed to check the others this weekend. 

One thing I noted and left instructions for them to check out was a welded plate of maybe 3/16" to 1/4" under the bearings. I'm wondering if these fans were designed for a spherical roller bearing pillow block and the 2-15/16" Sleeveoil bearings have a shorter shaft height so they added the plate.  If the plate wasn't flat, it would act like a spring even after torquing the hold-down bolts.

I don't want my fans running at .39 ips peak if I can help it but I don't think I have ever seen a shutdown level that low.


Vibe-Rater

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Reply with quote  #9 
Danny, I don't get involved with alignments but a trusted accomplice does. We had a vacuum pump and site alignment personnel assured us it was perfect. But we were still measuring 40 mm/s (15"/s) 1x. Worse than before alignment. So we questioned it.  Turned out it was several mm out everywhere with pump sitting low. so after trusted accomplice recommended serious plates to lift pump all was good.

Moral of the story. Only believe alignment reports from trusted sources.  Still running smoothly now. rgds  Not to say all inhouse is not capable but you always have to question and check.
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