The major issue for premature failure in wind-turbine gearboxes is bearing failure, which leads to gearbox failure. A wind-turbine gearbox will not survive if the oil is not clean and especially if the hard ferrous particles are not removed from around the bearings.1
The LaserNet 230 particle counter and ferrous debris monitor has been shown to be an excellent analytical tool for end users to diagnose wear faults in various machine applications such as gearboxes, engines, and transmissions. The wear generated in a wind-turbine gearbox is a function of load, speed, and lubricant condition. The lubricant must be correctly specified for the turbine gearbox’s idealized operating load and speed, and its condition must be carefully monitored in order to maintain the required lubricant film thickness in these regimes.
Ever-changing wind conditions and large variations in climates make wind-turbine condition monitoring extremely challenging. As a result, careful continuous automated monitoring of these critical and expensive assets is required. The National Renewable Energy Laboratory (NREL) uses the Lasernet Fines (LNF) technology in drive-train wind-turbine monitoring. It has demonstrated and recommended that condition-monitoring using the LNF is critical to avoiding premature failures in wind turbines.2
Existing particle counter/auto sampler setups are not ideally suited for processing heavy batches of wind-turbine oil samples that also can vary considerably in contamination level. Extra dilution steps for the viscosity and the contamination levels are required, making them unsuitable compared to the standard clean oil hydraulic applications they were initially designed for.
Gearbox Wear Particles
The abnormal wear generated in any gear system typically comes from the pitch line of the gear tooth (fatigue) or the tip of the gear (severe sliding). At the pitch line, the contact is rolling, so the particles will be similar to rolling contact fatigue particles. The gear contact has an increased sliding component as the root or tip is approached, and the particles will show signs of sliding morphology.
This morphological wear data is extremely beneficial to the end user, and abnormalities in the gearboxes caused by large particle generation are easily identifiable when trends are established that can distinguish ferrous from non-ferrous material. Another critical feature of a wind-turbine gearbox is the bearings are both on the low- and high-speed stages, and any misalignment of these will induce failure.
Online techniques are offered as site solutions for customers with multiple windfarms, but the se are costly and not sensitive enough. Centralizing the testing analysis by sending samples to a regional service center offers the best cost to monitoring benefit when large volumes of turbine samples are involved. Contract labs with the right high-throughput screening tools are well-equipped to turn around data quickly and can recommend further action and/or testing if necessary.
In a high sample-throughput scenario, such as a contract lab running more than 100 samples per day, it’s important to be able to screen samples accurately so a more thorough and in-depth ferrography analysis can be done on those select samples that show abnormal LNF/ferrous readings.
Ferrography is still one of the leading root-cause analysis techniques, but it requires a complimentary screening methodology that closely links particle size distributions, morphology, and ferrous content.
LaserNet 230 and ASP Combination
By coupling a fully equipped LaserNet 230 with ferrous capability to an automatic sample processor (ASP), a full tray of 24 heavy (320cSt) wind-turbine gear-oil samples can be analyzed in about 2 1/2 hours. This continuous operation includes sample preparation and system cleaning. This all can be accomplished with no operator intervention and can yield the following results:
- Particle distribution greater than 4um (ISO 4,6,14 Codes)
- Wear Shape classification and distribution greater than 20um (p/ml)
- Percentage of large ferrous greater than 20um (p/ml)
- Total ferrous (ppm)
- Free water (Additional information on free water contamination present in the gearbox can also be reported from the water droplet classification.)
Analyzing Heavy Gearbox Oils
The ASP has been uniquely designed to complement the LaserNet 230 by using stir-and-wash sequences used to simulate the typical manual sample preparation steps like shaking and rinsing during routine LNF analysis.
The particles in the sample are homogenized using a special stir motor that rotates at an optimally selected speed. The stirring creates a vortex effect in the oil that sucks the particles from the bottom of the bottle and into the sample volume creating a homogenized sample. The speed is selected so as not to introduce excessive bubbles into the sample (the LaserNet 230 easily classifies bubbles greater than 20um and does not count them).
The stirring method using the ASP is ideally suited for heavy gear oils compared to manual shaking on a standalone system. The viscous forces of the heavy oil make manual shaking and homogenization of the particles impossible. The remaining bubbles left in the bottle also take a much longer time to be removed by vacuum degassing or ultrasonic methods.
Once the sample has been stirred, the contamination on the stirrer and sipper are cleaned using solvent spray jets in the wash tanks. The stirrer is then spin dried, so it will be ready for the next sample.
By running samples in this exact same mechanical manner over and over, the repeatability from sample to sample is excellent, and any deviation in sample data from a well-established trend can easily be identified by an analyst.
Continuous operation of the ASP/LaserNet 230 system is important when dealing with hundreds of gearbox samples a day with various levels of wear and contamination. In a typical batch of wind-turbine gearbox samples, it’s not uncommon to have high levels of water or additive breakdown often being reported as greater than 2 million particles. The LNF imaging system can easily handle such high levels of contamination without any issues, but it’s important that the next sample is not cross-contaminated.
This is achieved by using a specially developed dynamic flush sequence that varies the amount of flushing required by continuously monitoring the particle count as the flush is taking place. A cleanliness threshold is set in the software, and once the count gets below this value, the flush stops, and the sample progresses. This is important as a typical wind-turbine gearbox running on a relatively new oil may only contain 1,300 to 10,000 parts per milliliter or an ISO code from 18 to 20. The incorporation of a bubble valve into the ASP flush line simulates a manual operator adding pockets of air shown to dramatically speed up flushing. It also removes excessive contamination quicker than a straight stream of solvent.
The ASP/LaserNet 230 ferrous combo is an ideal screening solution for wind-turbine gearbox applications where sample volumes are high. The system can accurately and repeatedly identify problem samples from a trend based on particle-size distributions. The source of the wear can be identified using the shape classifier and the ferrous information.
- Andy Milburn; Milburn Engineering, Wind Turbine Gearbox Wear and Failure Modes and Detection Methods, NREL — Wind Turbine Condition Monitoring Workshop — September 19-21, 2011.
- Shawn Sheng; NREL, Investigation of Various Wind Turbine Drivetrain Condition Monitoring Techniques — 2011 Wind Turbine Reliability Workshop, August 2-3, 2011, Albuquerque, New Mexico.
Suala kuu kwa ajili ya kushindwa mapema katika magurudumu ya turbine upepo ni kushindwa bearing, ambayo inaongoza kwa kushindwa gearbox. Kioo cha turbine ya upepo haitaendelea kuishi ikiwa mafuta hayajafichwa na haswa ikiwa chembe ngumu za chuma haziondolewa kutoka karibu na magurudumu. - LaserNet 230 - Mfuatiliaji wa chembe na mchanganyiko wa chuma - imeonyeshwa kuwa chombo bora cha uchambuzi kwa watumiaji wa mwisho kugundua makosa ya kuvaa katika matumizi mbalimbali ya mashine kama vile gearbox, injini, na transmissions. Uharibifu unaotokezwa katika sanduku la gia la turbine ya upepo ni kazi ya mzigo, kasi, na hali ya lubricant. Lubricant lazima kuwa sahihi maalum kwa turbine gearbox's idealized kazi mzigo na kasi, na hali yake lazima uangalie kwa uangalifu ili kudumisha required lubricant filamu unene katika serikali hizi. Hali za upepo zinazobadilika-badilika na tofauti kubwa katika hali ya hewa hufanya ufuatiliaji wa hali ya turbine ya upepo kuwa changamoto kubwa sana. Matokeo yake, uangalifu kuendelea automatiska ufuatiliaji wa mali hizi muhimu na ghali inahitajika. National Renewable Energy Laboratory (NREL) hutumia teknolojia ya Lasernet Fines (LNF) katika ufuatiliaji wa turbine ya upepo ya gari. "Kama ilivyoelezwa hapo juu, ""Ufuatiliaji wa hali kwa kutumia LNF ni muhimu ili kuepuka kushindwa mapema katika turbines za upepo.""2 Mipangilio ya sasa ya ""particle counter"" au ""auto sampler"" haifai kwa usindikaji wa sampuli kubwa za mafuta ya turbine ya upepo ambayo pia inaweza kutofautiana sana katika kiwango cha uchafuzi." Hatua za ziada za kuyeyusha kwa viscosity na viwango vya uchafuzi zinahitajika, na kuwafanya wasifaa ikilinganishwa na matumizi ya kawaida ya mafuta safi ya hydraulic ambayo yaliundwa awali. Gearbox Wear Chembechembe ya abnormal kuvaa zinazozalishwa katika mfumo wowote gear kawaida inatokana na pitch line ya gear jino (uchovu) au ncha ya gear (kubwa sliding). Katika mstari wa pitch, mawasiliano ni rolling, hivyo chembe itakuwa sawa na rolling mawasiliano uchovu chembe. Kuwasiliana gear ina kuongezeka sliding sehemu kama mizizi au ncha ni kukaribia, na chembe itatoa ishara ya sliding morphology. Data hii ya kuvaa ya morphological ni muhimu sana kwa mtumiaji wa mwisho, na kasoro katika gearboxes zinazosababishwa na uzalishaji mkubwa wa chembe zinaweza kutambuliwa kwa urahisi wakati mwenendo unapoanzishwa ambao unaweza kutofautisha chuma na nyenzo zisizo za chuma. Sehemu nyingine muhimu ya gearbox ya turbine ya upepo ni kuwa bearing ni wote juu ya hatua ya chini na ya kasi, na yoyote misalignment ya hizi kusababisha kushindwa. Utaratibu wa mtandao wa uendeshaji wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo wa upepo. Kuunganisha uchambuzi wa majaribio kwa kutuma sampuli kwa kituo cha huduma ya kikanda hutoa gharama bora kwa faida ya ufuatiliaji wakati kiasi kikubwa cha sampuli za turbine zinahusika. Maabara ya mkataba na zana sahihi za upimaji wa high-throughput zina vifaa vizuri vya kugeuka data haraka na inaweza kupendekeza hatua zaidi na au kupima ikiwa ni lazima. Katika hali ya kiwango cha juu cha sampuli, kama vile maabara ya mkataba inayoendesha sampuli zaidi ya 100 kwa siku, ni muhimu kuwa na uwezo wa kuchunguza sampuli kwa usahihi ili uchambuzi wa ferrography kamili zaidi na wa kina uweze kufanywa kwenye sampuli hizo zilizochaguliwa ambazo zinaonyesha usomaji wa kawaida wa LNF. Ferrography bado ni moja ya kuongoza msingi sababu uchambuzi mbinu, lakini inahitaji complimentary screening mbinu ambayo karibu links chembe ukubwa usambazaji, morphology, na maudhui ya chuma. LaserNet 230 na ASP Combination: Kwa kuunganisha LaserNet 230 iliyo na vifaa kamili na uwezo wa chuma kwa processor ya sampuli ya moja kwa moja (ASP), tray kamili ya sampuli 24 nzito za mafuta ya turbine ya upepo inaweza kuchambuliwa katika masaa 2 na nusu. Uendeshaji huu wa kuendelea ni pamoja na maandalizi ya sampuli na kusafisha mfumo. Hii inaweza kufanyika bila uingiliaji wa operator na inaweza kutoa matokeo yafuatayo: - Usambazaji wa chembe kubwa kuliko 4um (ISO 4,6,14 Codes) - Uainishaji wa Umbo la Kuvaa na Usambazaji wa Zaidi ya 20um (ppm) - Asilimia ya ferrous kubwa zaidi ya 20um (ppm) - Jumla ya ferrous (ppm) - Maji ya bure (Maelezo ya ziada juu ya uchafuzi wa maji ya bure katika gearbox pia inaweza kuripotiwa kutoka kwa uainishaji wa matone ya maji). "Kuchunguza mafuta nzito ya gearbox ""ASP"" imeundwa kipekee ili kukamilisha LaserNet 230 kwa kutumia mfululizo wa ""kuchanganya na kuosha"" kutumika kuiga hatua za kawaida za maandishi ya kutayarisha sampuli kama vile kutikisa na kuosha wakati wa uchambuzi wa kawaida wa LNF." Chembe katika sampuli ni homogenized kutumia maalum stir motor kwamba inazunguka kwa kasi bora kuchaguliwa. Mzunguko huo huunda athari ya vortex katika mafuta ambayo huchukua chembe kutoka chini ya chupa na kuingia katika kiasi cha sampuli na kuunda sampuli ya homogenized. LaserNet 230 ni rahisi kwa ajili ya kuamua aina ya Bubbles kubwa kuliko 20 um, na haina kuhesabu yao. Njia ya kuchochea kwa kutumia ASP inafaa sana kwa mafuta mazito ya gear ikilinganishwa na kutikisa kwa mkono kwenye mfumo wa kujitegemea. Nguvu zenye kunata za mafuta mazito hufanya kutikisa kwa mikono na kuunganisha chembe hizo isiwezekane. Bubbles zilizobaki kushoto katika chupa pia kuchukua muda mrefu zaidi kuondolewa na vacuum degassing au mbinu ultrasonic. Mara baada ya sampuli imekuwa kutikiswa, uchafuzi juu ya stirrer na sipper ni kusafishwa kwa kutumia solvent kunyunyizia jets katika tangi kuosha. Kisha kichocheo hicho huyeyushwa, hivyo kitakuwa tayari kwa ajili ya sampuli inayofuata. Kwa kuendesha sampuli kwa njia hii sawa ya mitambo mara kwa mara, kurudia kutoka sampuli hadi sampuli ni bora, na kupotoka yoyote katika data ya sampuli kutoka kwa mwelekeo uliosimamiwa vizuri inaweza kutambuliwa kwa urahisi na mchambuzi. Uendeshaji wa kuendelea wa mfumo wa ASP LaserNet 230 ni muhimu wakati wa kushughulika na mamia ya sampuli za gearbox kwa siku na viwango tofauti vya kuvaa na uchafuzi. Katika kundi la kawaida la sampuli za gearbox ya turbine ya upepo, sio kawaida kuwa na viwango vya juu vya maji au uharibifu wa nyongeza mara nyingi kuripotiwa kuwa kubwa kuliko chembe milioni 2. LNF mfumo wa picha inaweza kwa urahisi kushughulikia viwango vya juu vya uchafuzi bila matatizo yoyote, lakini ni muhimu kwamba sampuli ijayo si msalaba-chafu. Hii ni mafanikio kwa kutumia maalum maendeleo dynamic flush mfululizo kwamba inabadilika kiasi cha flushing required kwa kuendelea kufuatilia chembechembe kuhesabu kama flushing ni kuchukua nafasi. Kiwango cha usafi huwekwa katika programu, na mara tu hesabu inapopungua thamani hii, kufulia kunasimama, na sampuli inaendelea. Hii ni muhimu kwa sababu kawaida turbine upepo gearbox kuendesha juu ya mafuta ya hivi karibuni inaweza tu kuwa na 1,300 hadi 10,000 sehemu kwa mililita au ISO code kutoka 18 hadi 20. Kuunganisha valve ya Bubble kwenye mstari wa kusafisha wa ASP huiga mwendeshaji wa mwongozo akiongeza mifuko ya hewa iliyoonyeshwa kuharakisha haraka kusafisha. Pia huondoa uchafuzi mwingi haraka kuliko mtiririko wa moja kwa moja wa kioevu. ASP LaserNet 230 ni chombo cha kuchunguza chembe za magurudumu ya turbine ya upepo ambayo inahitajika kwa kiwango cha juu cha sampuli. Mfumo unaweza kwa usahihi na mara kwa mara kutambua sampuli tatizo kutoka mwenendo kulingana na usambazaji chembe ukubwa. Chanzo cha kuvaa inaweza kutambuliwa kwa kutumia sura classifier na habari ferrous. "Mwanzilishi wa ""Mashine ya Ufuatiliaji wa Hali ya Turbine ya Upepo"" (Win-Turbine Gearbox Wear and Failure Modes and Detection Methods) wa NREL, Andy Milburn, alisema: ""Kuna uwezekano mkubwa wa kutengeneza turbine ya upepo kwa muda mrefu." "Shawn Sheng, Mkurugenzi wa Utafiti wa Vipimo vya Ufuatiliaji wa Hali ya Turbine ya Upepo, ""Workshop ya Uaminifu wa Turbine ya Upepo ya 2011,"" Albuquerque, New Mexico, Agosti 2, 2011"