Tagged With "fan"

Topic

Balancing duel rotor variable pitch axial fans

John.OGE ·
We are a coal fired power plant and one of our units has large duel rotor variable pitch axial fans for Induced Draft made by Westinghouse. Does anybody know balancing experts (SME) that are familiar with these kind of units?
Topic

Crude Oil Boilers & AQCS

Y7 ·
Greetings,  2 crude oil boilers are used to generate steam and air quality control system AQCS is provided at end of each, the whole system is provided by Macci company. ID fans and FD fans are provided by Boldrochi. The fans encountered several...
Topic

Fan Wall, Fan Array, Fan Matrix?

USMC 08 ·
Regardless of what you call it... Any tips on installing permanent mounted accelerometers on these stacked systems?
Topic

Material Coating on fan impeller blades causes high vibration

Saif Khan ·
We are facing fine material coating on the impeller blades of system fan in Cement Grinding area. Can any one guide me about the reason of it and can suggest the solution?
Topic

natural frequency

alainraad ·
how to change a centrifugal fan natural frequency without adding weights
Topic

Mismatched Bearings & Housings

Rusty Cas ·
*
Topic

Pillow Block Unusual High Sound

lintu ·
ID Fan Pillow Block has very unusual sound. Grease type roller bearing dodge 22211kc3ah. Any comments for solution?
Topic

seal air fan (Radial Fan) Axial Vibration

y@sh ·
hello guys, help me out from this problem the radial fan getting 7.6 orders and its harmonics . high vibration on axial side 17 mm/sec .fan have 11 no.of vanes and that 7.6 orders matching with bearing outer race but after checking the bearing outer races are normal and inner race clearances was 0.3 mm. i am unable to identify the this problem please,help me guys
Topic

“STRANGE” FIRST ORDER (1X) ON FAN SYSTEM

dominich.vo ·
Hi all, I would like to discuss one case in fan system. This is MV wound rotor . Nameplate speed is 16.33 Hz (980 RPM) . However, in spectrum data indicate peak at first order is 15.25 Hz (~915 RPM) . This is so strange with what I learn about...
Topic

Vibration Isolators

MarkSl ·
Hi Gents, I took some vibration data today from an overhung fan which is visually vibrating at all locations including the structure and floor. The spectrum shows very high 1xF which is worst at the fan locations (up to 37mm/s RMS) . The 90KW motor...
Reply

Re: Mismatched Bearings & Housings

OLI ·
I have lately had a couple of cases where not even buying a set is a guarantee that it works, brand new from a 3-letter supplier common around here. Production plant is an hour drive from here. Still cast housing was measurable not in spec... It gave similar indication. Plant sent them in for warranty claim, unknown result... If the rings are the axial locking ones I seen all combinations including like everywhere in both bearings and that is not good. Olov
Reply

Re: Pillow Block Unusual High Sound

Edwin de B ·
Hard to say since you don't show acceleration spectra, while that is mostly where noise is seen. What does it sound like? screaming? It could be that rolling elements are slipping. A small offset in alignment might help. (Just a guess based on experience)
Reply

Re: Pillow Block Unusual High Sound

OLI ·
I second that. I used that on CARB bearings that is a roller bearing of sorts. If it sound loud and nothing much is found in data, increase the load by a light alignment adjustment in the wrong direction to give it some load and that do make the sound go away and possibly increase the bearing life. Olov
Reply

Re: Pillow Block Unusual High Sound

Dan Timberlake ·
any history ? Brand new installation, first bearing replacement after a long and heathy life, recent change to space age high temperature grease, or ??
Reply

Re: Balancing duel rotor variable pitch axial fans

arie mol ·
Over the recent 25 years I have balanced many of these MWatt Industrial fans worldwide. Do you face a specific problem?
Reply

Re: Balancing duel rotor variable pitch axial fans

John.OGE ·
This fan has proven difficult to balance. Not many plants use a two stage variable pitch axial fan. The specific fan is a Westinghouse Sturtevant Two-Stage Induced Draft Axial Fan (885 RPM, 7000 hp, hydraulically actuated blade pitch). Have you balanced similar types of fans?
Reply

Re: Pillow Block Unusual High Sound

lintu ·
thanks Edwin. I suspect as well of alignment. I will make sure that not only the internal clearance has been written down but also the bearing on adapter sleeve was properly installed by matching the tapered bore of bearing against tapered O.D. of adapter sleeve.
Reply

Re: Pillow Block Unusual High Sound

Edwin de B ·
To be clear: you get slipping rolling elements when alignment is 'to good'. This happens sometimes with bearings of very hard material (like SKF Explorer series) in combination with to little radial load on the bearing.
Reply

Re: Mismatched Bearings & Housings

dog ·
Rusty, I have seen this before also. It got to the point at last job we checked housings before every install even if Housings and bearings were same make. I have never seen 2 locking rings in same bearing. Noticed this fan is running in grease. I could be wrong but speed seems high for grease. I'm new on board so don't beat me up to bad.
Reply

Re: Mismatched Bearings & Housings

Dan Timberlake ·
Hi Rusty, What type of bearing, size and number? This SKF cross section seems to indicate a "locating ring" on each side. http://www.skf.com/binary/21-1...EN_tcm_12-151607.png Assuming the main features like centerline height etc, are right, I'd consider using another housing if the housing bore measured reasonably close to having the proper fit. Actually it is probably best to check ANY pillow block housing before use. When Lacking inside and outside micrometers Plastigage is a decent...
Reply

Re: Balancing duel rotor variable pitch axial fans

arie mol ·
John, Have you balanced similar types of fans? No for Westinghouse. Yes for Howden, fans were made in the Netherlands and Denmark. In coal fired plants. Problems encountered that will make balancing troublesome: * Loose parts in hollow impeller hub(s). Solid stuff like corrosive settlements of pitch control lub oil leakage into hub. A repeated initial run proves such unbalance instability: different amplitudes and/or phase angles for both runs. Clean hub first. * A resonant condition near...
Reply

Re: Mismatched Bearings & Housings

Steve Ciesla ·
Theoretically, a mixed housing and bearing set should work, IF the fit matches your expectations. Specifying an ISO fit (after an issue or two with a specific installation), typically falls into a "gray" area. It would be interesting to know what the bearing housing manufacturers are using for their default fits. Buying a "set" does not guarantee that the fit matches your expectations, but it is probably better than grabbing a random housing and bearing of the shelf. This is definitely one...
Reply

Re: Mismatched Bearings & Housings

vibramac ·
But when I'm explaining something, and they lose eye contact, then I stop, because I'm wasting my breath. Sometimes I get a little "eye roll" and that's the last thing I ever tell that individual. I'm very much the same. Once the cell phone is answered or text messaging is stareted, I shut down with my explanations/advance. Cell phones on the job should be disallowed!!!!!!!!!
Reply

Re: Mismatched Bearings & Housings

John from PA ·
What about manufacturers that supply interchange charts? http://www.timken.com/en-Us/pr...erchangeSheets06.pdf
Reply

Re: Mismatched Bearings & Housings

John from PA ·
Rusty, that is because after many years of experience and self-training, we are now experts; e x (a former) spurt (a drip under pressure ).
Reply

Re: Mismatched Bearings & Housings

IrishMark ·
Rusty I had a place like that, I was seen as the guy pointing out how the maint techs weren't doing they're job....so I learned quick they weren't interested in my opinion..only they're management wanted the bottom line verdict on machine condition and possible upcoming issues, thankfully that company has now outsourced they're maint and surprisingly those guys are on they're game, then again there continued employment depends on it.
Reply

Re: Mismatched Bearings & Housings

John from PA ·
Ever wonder what the statement (seen in many coupling catalogs) "Interchangeable with other AGMA industry standard gear couplings" means? It may also be surprising to some that there exists a certain amount of interchangeability between gear couplings made by differing companies. Take a Sier-Bath gear coupling built to the American Gear Manufacturers Association (AGMA) standard dimensions and it will mate half for half with all other gear couplings built to AGMA standards. This applies up to...
Reply

Re: “STRANGE” FIRST ORDER (1X) ON FAN SYSTEM

John from PA ·
A wound rotor induction motor has a stator like the squirrel cage induction motor, but the rotor windings are connected through slip rings to external resistances. Motor speed may be varied by varying the resistance in the rotor circuit. Usually speed control technique is useful over a range of 50% to 100% of full speed. Often the controller uses wire-wound resistors that are progressively shorted out manually or by magnetic contactors controlled electronically. Relatively new wound-rotor...
Reply

Re: “STRANGE” FIRST ORDER (1X) ON FAN SYSTEM

dominich.vo ·
Hi John. I do not think so, rotor always connect with a resistance system but after start-up,Magnetic contactors close by-pass to remove liquid resistance out of rotor system. I also do more MCSA _online test, the effective (95%) and power factor (cos(phi) = 0.9) are still high. I do not think that is controller issue.
Reply

Re: “STRANGE” FIRST ORDER (1X) ON FAN SYSTEM

Edwin de B ·
Could it be that the by-pass circiut has some resistance? The 15.25 Hz is definitely the 1X and indeed that means a big slip on motor rpm.
Reply

Re: Crude Oil Boilers & AQCS

candy ·
Has the OEM responded commitedly after sales?
Reply

Re: Crude Oil Boilers & AQCS

Y7 ·
There is inadequate support from OEM and manuals are not comprehensive enough for the troubleshooting and maintenance. The units were supplied 10 years ago. any idea if such units from similar supplier are used somewhere else?
Reply

Re: “STRANGE” FIRST ORDER (1X) ON FAN SYSTEM

nugrous ·
I agree with Edwin de B. 15.25 Hz is definitely the running speed of the motor and the driven. It is obviously indicated on the spectrum of the driven you sent. Your motor has a big slip problem. Some factors could contribute to excessive motor slip. For example: the load of the motor (fan) or the abnormal voltage. You could check the motor load from the current. High ampere means high load. High load can increase the slip. The motor slip also increases proportionally to the square of the...
Reply

Re: Vibration Isolators

Dan Timberlake ·
Any historical vibration data ? To know when the busted isolators may have finally failed, or how they were working last year. Are there complaints from the occupants about noise or vibration at any of the fan's frequencies? If the floor is vibrating, the isolators are not "isolating". Selection of isolators is way more complicated than looking up the weight capacity in a table. ESPECIALLY when the equipment is not on a slab on the ground.
Reply

Re: Vibration Isolators

Ron Brook ·
The amount of clips on that fan does not sound right. If you want to try to balance the fan, I would recommend taking the belts off and seeing what the fan does statically. As far as the isolators are concerned, their job is to keep the residual vibration from entering the structure. They have nothing to do with quieting down the fan itself. Also, not a big fan of motors mounted on the side of the fan support. Usually end up with very bad belt stability, meaning the motor vibration on the...
Reply

Re: Vibration Isolators

Alin02 ·
Its very difficult some of the time when such kind of things happens in the unit. And the situation becomes more complicated when you choose wrong isolators without knowing the working capacity or style, because it not only affects the machine even other things also as in your case happening. you should use machine removing the belt independently first and need to see what happen, it there any pulley problem because as the isolator is not concern with this.You should also check the alignment...
Reply

Re: seal air fan (Radial Fan) Axial Vibration

Walt Strong ·
" that 7.6 orders matching with bearing outer race but after checking the bearing outer races are normal" You have outer race fault frequency with 1xSS sidebands (modulation), so it sure looks like an outer race fault! How did you or someone actually "check the outer race"? Most bearings require destructive disassembly (cut apart) to actually see the full bearing race surface. Don't get lost in a pile of data! Walt
Reply

Re: seal air fan (Radial Fan) Axial Vibration

Shurafa ·
Were these spectra collected before after the "bearing checks"? Did you replace the bearings or you reinstalled them? It looks there is a bearing defect. Regards-Ali M. Al-Shurafa
Reply

Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
Above spectrums are After checking the bearings and alignment and we find inner clearances but there is no outer race defect physically
Reply

Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
We check the bearing clearances with feeler gauge inner and outer
Reply

Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
We disassemble the both de and nde bearing and checked physically but there is no Outer race defect
Reply

Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
bearing images
Reply

Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
BEFORE ALIGNMENT
Reply

Re: seal air fan (Radial Fan) Axial Vibration

electricpete ·
[quote] inner race clearances was 0.3 mm.[/quote] Can you explain more about this measurement? I hope it is not between bearing and shaft (that should not be clearance) What style bearing is it?
Reply

Re: seal air fan (Radial Fan) Axial Vibration

montaser ·
I advice you to make mark using (correction pen) between the bearing outer race and lower part of housing and another mark between bearing inner race and shaft, and keep the fan running for some hours, then stop and inspect the marks position for the possibility of bearing rotation inside the housing.
Reply

Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
Tnq for reply its not b/w shaft and bearing ,clearances are b/w balls and bearing inner ring.
Reply

Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
thank you sir but it is a heavy equipment . so,it's impossible to open the machine at present conditions.
Reply

Re: seal air fan (Radial Fan) Axial Vibration

Jim1 ·
Oil filled housing? Did you sample the oil? What caused the satin finish on the rollers and inner raceway?
Reply

Re: seal air fan (Radial Fan) Axial Vibration

Walt Strong ·
Y@SH, I looked at your three photos. None of the photos show the surface of the outer race/ring that is in the contact path of the rollers. The bearing would have to be destructively taken apart to do so. Therefore your limited inspection does not prove or disprove an outer race defect. The only way to do that would be to remove the grease and cut the bearing rings apart. You can save that activity for a later date when you change the bearing. If you actually put in new bearing when those...
Reply

Re: Fan Wall, Fan Array, Fan Matrix?

Walt Strong ·
Centrifugal fan wheel mounted directly on motor shaft. I guess your main interest would be detecting motor bearing faults and fan unbalance. Other possible detectable faults might include fan airflow blockage and motor electrical faults. I would consider one accelerometer per fan mounted on the motor DE bearing housing or on the motor case near the terminal box. The accelerometer cable can run along with the motor power lead to a convenient location to a junction box with BNC terminals or to...
×
×
×
×