Sign up Calendar Latest Topics Donate
 
 
 


Reply
  Author   Comment   Page 3 of 3      Prev   1   2   3
Ralph Stewart

Avatar / Picture

Sr. Member
Registered:
Posts: 235
Reply with quote  #31 
SNORMAN,

"Today i went up and they were running at 77% which is just a setpoint not truly related to 77% of 3600( I should just start using rpm) . The rpm was around 2800 and the floor about ten feet away was .36ips while bearing was around .1ips it is this piont on the floor that it is always most evident highest amplitudes around 2800 rpm lower at 2500 and 3200 see attachment  "

If the fan inboard has increased from 0.1 in/sec to 0.4 in/sec, did the floor increase the same exponential amount to 1.44 in/sec? [confused]

Thanks and Have a Great Day,
Ralph

__________________
Ralph Stewart
AlertAnalytical.com
SNORMAN

Member
Registered:
Posts: 59
Reply with quote  #32 
Well it was definitely shaking a lot. I did not take time to see. i immediately told them to slow the fan down 1700 Rpm. When we tore it down there as 4 times the clearance in the outboard bearing. One of the operators thought it would be ok to run at 77% for several hours. there was a lot of looseness in the bearing which created misalignment and a wear ring in the pillow block where the bearing was setting. there was also a slight lack of lube condition. all of these contributed to the 1xts excitement. but we still have the same issue with floor resonance at 70-85% worst being right at 80%(2800 rpm). for now they are running no higher than 65% until the Bosses get solution figured out.
Ralph Stewart

Avatar / Picture

Sr. Member
Registered:
Posts: 235
Reply with quote  #33 
Quote:
When we tore it down there as 4 times the clearance in the outboard bearing.


Didn't you mentioned in your other thread that the fan bearing were just recently changed?

What type bearings are they, tapered sleeve mounted or a straight bore with interference fit?

Seems like this thing is, as you mentioned, "problematic". [smile]

Hope you get it figured out.

Thanks and Have a Great Day,
Ralph

__________________
Ralph Stewart
AlertAnalytical.com
Alex

Avatar / Picture

Sr. Member
Registered:
Posts: 204
Reply with quote  #34 
You said 3 mm/s vibration on the bearing was enough to cause some floor disturbing vibration. So I doubt the only issue you have had is in increased bearing clearance. It is pitty you didn't have the peakvue spectrum as I said before there were some obvious 1x harmonics in the velocity spectrum.
SNORMAN

Member
Registered:
Posts: 59
Reply with quote  #35 
Quote:
Originally Posted by Ralph Stewart


Didn't you mentioned in your other thread that the fan bearing were just recently changed?

What type bearings are they, tapered sleeve mounted or a straight bore with interference fit?

Seems like this thing is, as you mentioned, "problematic". [smile]

Hope you get it figured out.

Thanks and Have a Great Day,
Ralph

Ya they were quite new. they are a tapered adapter sleeve
Ralph Stewart

Avatar / Picture

Sr. Member
Registered:
Posts: 235
Reply with quote  #36 
Quote:
quote on 11-22-18:
When we tore it down there as 4 times the clearance in the outboard bearing.

Quote on 12-03-18:
Ya they were quite new. they are a tapered adapter sleeve


Being a tapered sleeve bearing, the looseness was from what?

The tapered sleeve slipping its fit to the Inner Race causing clearance to increase between the rollers and the outer race?

Was the sleeve loose on the shaft and "spinning"/"slipping" on the shaft?

After 10 or 12 days I am guessing it is back running. [smile]

Is the floor and fan vibration better now?

Or did they not try to balance the fan yet, to a very, very low amplitude, in an effort to help the floor?

Thanks and Have a Great Day,
Ralph

__________________
Ralph Stewart
AlertAnalytical.com
fburgos

Sr. Member
Registered:
Posts: 670
Reply with quote  #37 

Quote:
Originally Posted by SNORMAN
Here we go 1 order amplitudes at 70 80 and 90 %. the hole in the floor has been there it has a duct running through it. floor vibrates in all directions. What is considered very balanced balanced as far as amplitudes go?



I was about to point out that spectrum looks like bearing problem, but I its too late I guess.

Im interested in solving the resonance problem, do you have spectrums o cross phase on the floor
SNORMAN

Member
Registered:
Posts: 59
Reply with quote  #38 
Quote:
Originally Posted by Ralph Stewart


Being a tapered sleeve bearing, the looseness was from what?

The tapered sleeve slipping its fit to the Inner Race causing clearance to increase between the rollers and the outer race?

Was the sleeve loose on the shaft and "spinning"/"slipping" on the shaft?

After 10 or 12 days I am guessing it is back running. [smile]

Is the floor and fan vibration better now?

Or did they not try to balance the fan yet, to a very, very low amplitude, in an effort to help the fl
Thanks and Have a Great Day,
Ralph


The looseness was from bearing wear increasing the clearance between out and inner race to rolling elements and vibration caused a clearance between the outer race and the pillow block. we did not have time to balance it. it is back running and is a bit better. but it does not get ran over 65% now until further notice
Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.