Tagged With "Gearbox"

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Abnormal vibration at gearbox of pump

Ngo Dinh ·
Hi everyone, I have a case with gearbox of the pump which after maintenance (checking gear, backlash, realign gear set and whole train) the gearbox operated with higher vibration with unstable amplitude as file attached. I also open the sign plate at top of gearbox to see the teeth but it is noted that there is no teeth failure. With the input gear with 87 teeth and pinion with 33 teeth, I think that at assembly time, the maintenance staff do wrong phase meshing of teeth contact. So, the...
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An unknown frequency observed at Gearbox

sany ·
Hi, This is equipment of Steel Industry from Bar Rod Mill unit. Equipment is Mill Stand, Which is having reducer gear. The Input shaft have 24teeth and mating gear has 63teeth. Intermediate having 19,66 teeth and output shaft having 31,31teeth. I didnt have any problem with vibration whenever the higher dia bar is rolled vibration will be 4.0mm/sec peak and during lesser dia bar rolled it will 2.5mm/sec peak. The spectrum is showing a high amplitude dominant peak of 73.1orders of input speed...
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belt drive gearbox vibration

Hossam 2 ·
im facing a strange problem at the plant is that the drive set for the belt is vibrating excessively at the beggining of the operation but after while the vibration reduced sharply after 1 hour i will provide you by the complete data shortly
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Broken Gear Shaft

Jenish ·
Dear Experts, Can anybody give any expert opinion about this Broken Shaft? It is from a stand gearbox of a rolling mill..
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Chain Lift Motor/Gearbox 1/2X

Mike Gawlik ·
I am hoping someone can help me out a little. I am fairly new to the PdM game and since we started to perform vibration on our VFD driven motor/gearboxes that run a chain lift for ride vehicles. (Think rollercoasters). Anyway, the issue we see on all of the motors and gearboxes that run these lifts is a high peak around 1/2x (it varies slightly per ride/lift) In the attached file, you can see that we have a 0.533 order peak on all measurement points for the motor and gearbox. This value will...
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Creating an epicyclic gearbox with RBM wizard

Ardalan ·
Greetings, I have some problems when trying to create an epicyclic gearbox with RBM wizard in AMS machinery suite, we have a gear box that has a bevel gear as an input from the drive, which is connected to the first stage's sun by a bull gear and a shaft, the problems to create such gearboxes with RBM is as follow: You can only create one type of gearboxes at time (simple or epicyclic), and when you choose epicyclic you will not be able to have the bevel gear inside, you only have the...
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Cross Phase analysis issue

Hossam 2 ·
Problem is in motor if atox mill (insaldo) The free end has a 4xts dominent vibration we have balanced it to reduce one x from 3 to 0.3 mm/s vut still over all value is 5.5mms wiz 4xts sharp  The phase relationship is weired as 180 phase difference between the drive end and non drive end in the vertical direction ..i suspect misalignment problem and the other issue is that no sensors give exact reading across the coupling specially in the gearbox side always give real value in the motor...
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Conveyor Gearbox high axial vibration

VANDA BAB ·
Hi every one   iam having problem in Gearbox high axial vibration (High speed I/p shaft)   Conveyor for coal handling in Thermal power station maintaining high axial vibration: (H: 4.0mm/sec    V: ...
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Cooling Tower Gearbox Failures

rgf12 ·
Attached is a report on a recent GB failure on one of our plants cooling tower fan drive gearboxes. It looks to me that the concentration of the failure area on the shaft side of the gear would indicate either a misalignment under load or a general...
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Cooling Tower Gearbox High Vibration

Fahad Qureshi ·
Hi! We have five induced draft cooling fans installed at our site. Recently we experienced high vibration on one of our fan gearbox having accelerometer installed in horizontal direction to gearbox casing. The max vibration was around 17 mm/sec and spectrum revealed GMFs with modulation where 2 x GMFs dominated for first set gears which are spiral bevel gears. Any idea what could be the probable issue?? Is it due to misaligned gears?? If yes then what factors could contribute to this issue?
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Duolec ISO 220 in gearbox

Vibsouth ·
Hi Guys have any of you tried running Duolec ISO 220 in a industrial gearbox? is it a good product?
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Re: TWA : gearbox

John from PA ·
The rate at which the bursts occur would indicate that the most likely source is related to the 1480 RPM input shaft. If you have the equipment and the access to the machine I would suggest an examination of the input shaft area with a strobe light. Examine the coupling area carefully including the keyway. The speeds of 1480/349 could be obtained by a 106 x 25 tooth combination which is a hunting tooth combination. Depending on the accuracy of those numbers the tooth combination might be...
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Re: TWA : gearbox

azizsuahid ·
thanks i dont have that access. its a diffrnt type of coupling for a 2MW motor tooth 18/78. i simply put approx. actual speeds.
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Re: TWA : gearbox

John from PA ·
Has that box ever been apart? And if so has anyone paid attention to the phase of assembly, of which there are 6 based on the 18 x 78 tooth combination? What is the past history of the problem? Something new or something that has been there for an extended period and is now getting worse?
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Re: TWA : gearbox

azizsuahid ·
1. Yes , many times, every 3 years, overhaul with new bearings and other things except the gears and housing. the gears have been for more than 10 years. no clear signs of wears. no oil analysis being carried out for years. 2. i am not aware the phase of assembly. i found your attached article regarding the phase which i will go through it 3. 3 weeks ago, there was a problem on the blower anchor bolt which we found it was a crack. we already fixed that by adding extra support. i 4. Readings...
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Re: TWA : gearbox

Walt Strong ·
"Based on TWA, can one conclude by saying impacts on the bearings or gears are too high and danger. meaning to say, the gearbox might fail in one week. " I would be surprised if any knowledgeable person on this BB would agree with this statement! You are putting way too much trust in one SMALL piece of data! Walt
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Re: TWA : gearbox

azizsuahid ·
noted and i will get more data
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Re: TWA : gearbox

azizsuahid ·
gearbox tag 2141.1A was replaced last month with inner race + bsf faults today gearbox tag 2141.1B is under investigation. see attachment. thanks for thorough reading and kindly comment.
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Re: Cooling Tower Gearbox High Vibration

John from PA ·
In my experience 2xGMF is indicative of a serious lubrication problem and/or severe wear of the tooth profile. I would be shutting down the suspect unit and examining it through the inspection openings. Almost all cooling tower drives have the inspection openings. Sometimes it is a steel bolted on cover, perhaps 10 cm x 15 cm. I have also seen cooling towers with relatively large pipe plugs that when removed enable you to see the mesh. If you post a drawing of one of the drives I can perhaps...
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Re: Cooling Tower Gearbox High Vibration

Fahad Qureshi ·
Dear John, Thanks for your quick response. Yes it has a inspection window. We actually removed that gearbox and found gears and their profile were intact. Even contact patters seemed to be fine. Backlash was within acceptable range. I will post pictures of the gear soon as well. Can a bad machine foundation contribute to misaligned gears. Regards, Fahad
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Re: Cooling Tower Gearbox High Vibration

John from PA ·
OK, sounds like you’ve taken care of the obvious. With respect to lubrication if you can do so through the inspection covers make sure there isn’t any plugged oil spray nozzle. I would also try to get a quick test on the lubricant to make sure it is in the range of the correct viscosity and the moisture content is low. Reading contact patterns is not the best indicator unless you clean and re-blue the teeth. Otherwise, you can’t tell the pattern from today, from one generated a year ago.
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Re: Cooling Tower Gearbox High Vibration

Fahad Qureshi ·
Thanks John for your valuable input. The casing is cast housing. I am attaching here casing and gears pictures. Please review and give your feedback. On the pinion spiral bevel gear, you can see a plate. This plate splashes oil within the gearbox whose level is maintained at 50 percent. Thanks
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Re: Cooling Tower Gearbox High Vibration

John from PA ·
The pictures seem to indicate the gearing is in decent condition. One thing, I see some reddish discoloration in a few spots; that isn't corrosion is it? Setting up bevel gears requires some skill; a good guide can be found at https://www.geartechnology.com...ear-installation.pdf
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Re: Cooling Tower Gearbox High Vibration

Fahad Qureshi ·
Thanks John. Yes it looks corrosion. What are your thoughts on casing as attached in pictures? Also, Would appreciate if you can provide your input on my below post, https://www.maintenance.org/to...1#472512025750694131 Thanks
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Re: Cooling Tower Gearbox High Vibration

John from PA ·
If indeed that is corrosion, then you need to be looking for a mechanism for water to be entering the unit and breaking down the lubricant. As far as the casing, my one comment is why is there an abundance of oil stains on the outside in the area of the nameplate? Is it just spillage from the disassembly operation, a possible crack????
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Re: Unknown Frequency in Planetary Gearbox

rgf12 ·
Is the peak at 1.7 of GMF? If so that has been known as a "ghost frequency" that Taylor and others attribute to the gear cutting machine. I've only encountered it once. The increase of amplitude is concerning. I would contact the GB manufacturer. Just a guess on my part.
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Re: Unknown Frequency in Planetary Gearbox

John from PA ·
What software generated the frequencies? And are you certain the 1st stage is a planetary arrangement (fixed ring or annulus)? The reason I ask is in a planetary arrangement, and for equally spaced planets, the number of teeth in the ring gear (R) is equal to the number of teeth in the sun gear (S) plus twice the number of teeth in the planet gears (P). So R = 2 * P + S. For the 1st stage S = 25 R = 308 P = 141 but 308 ≠ 2 * 141 + 25. It is 307. That would mean you do not have equally spaced...
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Re: Unknown Frequency in Planetary Gearbox

John from PA ·
This comment makes it seem like "ghost frequency" will be at 1.7X. This is not the case, although it might be the case for a very specific example in Taylor's book. I suggest you read https://www.bksv.com/media/doc/233-80.pdf , specifically pages 10 & 11.
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Re: Unknown Frequency in Planetary Gearbox

jvaugha1 ·
Thanks for your response. We use CSI 2140 and the Citrix machinery health manager software. I am sure it is a planetary gear with three planets in the first stage and three in the second. The frequencies I provided came from the manufacturer. Since I have been doing this for the last year I was told that the 23 in the order was the pinion but the information given to us from the manufacturer says 25 teeth. Have you ever experienced a difference like this in this style of gearboxes. As far as...
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Re: Unknown Frequency in Planetary Gearbox

John from PA ·
if the tooth counts came from the OEM, then likely they are correct. You will note that when I said R = 2 * P + S I clarified that with the statement "for equally" planets. Let me amplify on that just a bit and state "For evenly spaced planets that are engaging the next tooth at the same time, then both the number of sun teeth and ring gear teeth have to be evenly divisible by the number of planets. Since the sun tooth count is 25 (or even 23) and the ring tooth count is 308, then it can't...
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Re: Unknown Frequency in Planetary Gearbox

ADiN ·
The gearbox arrangement is parallel shaft – planetary – planetary. For planetary stages, fixed ring gears and rotating carriers are used. Number of teeth as below: İNPUT : 1487 rpm Input state – 61/26 Medium stage – 23/62/148 Output stage – 38/49/137 recaicev@gmail.com
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Re: Unknown Frequency in Planetary Gearbox

John from PA ·
"ADIN", are you referring to the same gearbox that the OP "jvaugha" was referring to?
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Re: Unknown Frequency in Planetary Gearbox

ADiN ·
NO
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Re: Unknown Frequency in Planetary Gearbox

John from PA ·
Then start your own topic rather than highjacking this thread and potentially confusing the issue!
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

John from PA ·
I see units of mm/s. Are you using an accelerometer and integrating to velocity? It might be something as simple as integration noise. Any details on the gearbox? Drawing, tooth counts, etc.? Are you certain it is a planetary arrangement, as opposed to a solar or star arrangement (see attached)?
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

vidya Sagar ·
Hi john, Yes,it is Planetary gearbox.Gearbox Model is CPNHX - 224.It is speed reduction gearbox and gear ratio is 82.87:1 the gear teeth details is as follows Input RPM 1489 Input pinion 25 Wheel/helical stage 52 1st Stage 2nd Stage Ring Gear Teeth 131 74 Planet Gear Teeth 53 27 Sun Gear Teeth 25 18 and as you said it might noise but am getting the same in other gearbox.Here the gearbox is used for raw meal grinding in cement plant.
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

Kishore kumar ·
Dear sir , What type of equipment connected to the Gearbox and the Vibration levels of that equipment and spectrum .Did you check decoupled condition Vibration spectrum of Gearbox to its equipment . Please share ,so that we could understand the problem .
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

John from PA ·
How many planets are in each stage? You didn't answer my question...are you using an accelerometer and integrating to velocity? I'm still of the opinion that you are likely seeing integration noise further, IMO, the fact that you have it on another machine supports noise as opposed to ruling it out as you seem to indicate. Just how does this machine feel? 6 mm/s (RMS) at 3.13 Hz is a displacement of almost 0.9 mm pp (34 mils). That machine should feel very rough! Note that I also used RMS...
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

Ralph Stewart ·
You may have already done this, but,...... Instead of a 2500 Hz Fmax, can you take data with a 0 to 200 Hz Fmax and 3200 lines of Resolution? This data will not be an "expanded" spectrum from a higher Fmax setting, but an actual acquired spectrum with a setting of 0 to 200 Hz and 3200 lines. Can not tell much about the data below the 1x peak, from this 2500 Hz Fmax, except it looks as though the data at the low end might be recovering from a "skislope" pattern. A true zoom in of this area...
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

vidya Sagar ·
Hi John Yes we use a accelerometer and it integrates to velocity. coming to planets,in first stage we have three planets and in second stage we have four planets.This gearbox is a movable gearbox where some pressure is applied for grinding(Normally runs between 10 to 15 mm/sec vibration).
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

vidya Sagar ·
Hi Kishore, The Equipment is roller press used for raw meal grinding.Motor is connected to gearbox via cardan shaft and gearbox connected to roller.Motor Vibration is 2.5 mm/sec in load condition and roller vibration varies from 5 mm/sec to 9 mm/sec.Roller DE spectrums are as follows.Decoupled condition means motor with gearbox ???
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

vidya Sagar ·
Hi Ralph, I have spectrum with 320 Hz,1600 lines in axial direction but not in horizontal.will take the data as you told once the machine starts.please find the spectrum for reference.
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

Ralph Stewart ·
Re: Reason for frequencies less than 1XRPM in planetary Gearbox
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Re: Reason for frequencies less than 1XRPM in planetary Gearbox

John from PA ·
You may want to request the anticipated frequencies from the manufacturer Eichoff. Based on earlier information, the 2nd stage has ring = 74 teeth, planet = 27 teeth and the sun = 18. If your tooth counts are correct, that may mean you have a non-factorizing gearset in the 2nd stage. In a non--factorizing planetary gear train the the number of teeth on either the sun gear or ring gear is not evenly divisible by the number of planets. In your case both the sun (18T) and ring (74T) are not...
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Re: High Axial Vibration in Gearbox

Soumya Mishra ·
The problem was finally solved. The base bolt vibration in a particular bolt was 8mm/sec as compared to others of 2-3mm/sec. We went with suspecting soft foot & after blue matching of GB foot & base around 20% contact area was found. After improving surface condition the contact are was around 50-60%. After the same , the vibrations reduced drastically to 3 mm/sec. Thank you guys for your response.
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Re: High Axial Vibration in Gearbox

ramonruiz ·
Good Job..
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Re: High Axial Vibration in Gearbox

John from PA ·
Just a "general" precaution when working on a gearbox with a fabricated steel housing . When installed by a knowledgeable technician, it is not that unusual to purposely shim the bottom of the gearbox casing unevenly in an effort to improve the tooth contact. Later, a millwright then checks for soft foot and finds and corrects the apparent problem but the supposed corrective action then results in poor contact. I always advise that when you find a fabricated housing shimmed in an unusual...
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Re: High Axial Vibration in Gearbox

Syed Huzaifa Ahmed ·
Just for info: In some cases, higher 2x axial vibration can occur in case of helical gears.
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Re: High Axial Vibration in Gearbox

Accelo1 ·
Check the service records! That's pretty funny.
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Re: High Axial Vibration in Gearbox

pal ·
so finally if it is soft foot the above prediction is correct bcoz soft foot correction is a part of alignment
 
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