1、Designation: D7917 14Standard Practice forInductive Wear Debris Sensors in Gearbox and DrivetrainApplications1This standard is issued under the fixed designation D7917; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONWear debris sensors, employing inductive sensing technologies (1, 2),2are able to quantify weardebris to classify size a
3、nd material composition (ferrous/non-ferrous) of metallic debris found inlubricating oil as a consequence of wear. Initial applications have been largely confined to industrialaero-derivative and aircraft gas turbine engine monitoring installations where the failure of high speedball and roller bear
4、ings results in significant secondary damage (2, 3). With an almost exponentialgrowth in the wind turbine industry, one engineering issue still to be resolved is the unacceptablegearbox failure rate (4). Wear debris sensors can play an important role in understanding the variedbearing failure modes
5、observed. There are thousands of inductive sensors operating in wind turbinesand other gearbox and drivetrain applications accruing millions of operational hours. While it isgenerally accepted that these sensors provide early warning of abnormal condition, the industry willbenefit from a standard pr
6、actice for data usage and interpretation.1. Scope1.1 This practice covers the minimum requirements for anonline inductive sensor system to monitor ferromagnetic andnon-ferromagnetic metallic wear debris present in in-servicelubricating fluids residing in gearboxes and drivetrains.1.2 Metallic wear d
7、ebris considered in this practice canrange in size from 40 m to greater than 1000 m of equivalentspherical diameter (ESD).1.3 This practice is suitable for use with the followinglubricants: industrial gear oils, petroleum crankcase oils, poly-alkylene glycol, polyol esters, and phosphate esters.1.4
8、This practice is for metallic wear debris detection, notoil cleanliness.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5.1 ExceptionSubsection 7.7 uses “Gs”.1.6 This standard does not purport to address all of thesafety c
9、oncerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D4175 Terminology Relating to Petrol
10、eum, PetroleumProducts, and LubricantsD7669 Guide for Practical Lubricant Condition Data TrendAnalysisD7685 Practice for In-Line, Full Flow, Inductive Sensor forFerromagnetic and Non-ferromagnetic Wear Debris De-termination and Diagnostics for Aero-Derivative and Air-craft Gas Turbine Engine Bearing
11、sD7720 Guide for Statistically Evaluating Measurand AlarmLimits when Using Oil Analysis to Monitor Equipmentand Oil for Fitness and ContaminationG40 Terminology Relating to Wear and Erosion2.2 ISO Standards:4ISO/TC 108 N 605 Terminology for the Field of ConditionMonitoring and Diagnostics of Machine
12、s1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-mittee D02.96.07 on Integrated Testers, Instrumentation Techniques for In-ServiceLubricants.Current edition approved Oct. 1, 2014. Published N
13、ovember 2014. DOI:10.1520/D7917-14.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informa
14、tion, refer to the standards Document Summary page onthe ASTM website.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Uni
15、ted States13. Terminology3.1 Definitions:3.1.1 condition monitoring, na field of technical activityin which selected physical parameters associated with anoperating machine are periodically or continuously sensed,measured, and recorded for the interim purpose of reducing,analyzing, comparing, and di
16、splaying the data and informationso obtained, and for the ultimate purpose of using interim resultto support decisions related to the operation and maintenanceof the machine.3.1.2 equivalent spherical diameter (ESD) , nthe equiva-lent spherical diameter of an irregularly shaped object is thediameter
17、 of a sphere of equivalent volume.3.1.2.1 DiscussionMetallic particles used to test and cali-brate inductive wear debris sensors are manufactured asspheres. A range of diameters, from smallest to largest sizesinvestigated, is utilized to vet the sensors capabilities andcalibrate it. Spheres ranging
18、from 40 m to 1000 m are usedfor this exercise. In vivo ferrous and non-ferrous debris willrarely be spherical; however all particles detected and countedare deemed to be spheres for reporting purposes, with thereasonable assumption that the ESD mass will be close to theequivalent mass of the non-sph
19、erical particle measured.3.1.3 inductive debris sensor, na device that creates anelectromagnetic field as a medium to permit the detection andmeasurement of metallic wear debris.3.1.3.1 DiscussionA device that detects metallic weardebris that causes fluctuations of the magnetic field. A devicethat g
20、enerates a signal proportional to the size and presence ofmetallic wear debris with respect to time.3.1.4 machinery health, na qualitative expression of theoperational status of a machine subcomponent, component, orentire machine, used to communicate maintenance and opera-tional recommendations or r
21、equirements in order to continueoperation, schedule maintenance, or take immediate mainte-nance action.3.1.5 metallic wear debris, nin tribology, metallic par-ticles that have become detached in wear or erosion processes.3.1.5.1 DiscussionThis practice declares 40 m ESD asthe lower limit of detectio
22、n for inductive debris sensors. Thishas not been shown to be a limiting factor for this real-timemonitoring.3.1.6 online sensor, na monitoring device that can beinstalled fully in-line or in a bypass loop with the lubricationsystem.3.1.6.1 DiscussionIn the former case, the sensor should becapable of
23、 allowing the full flow of the lubrication fluid totravel through unimpeded. In the latter case of the bypass loop,care must be taken to ensure a representative sample is flowingthrough the sensor.3.2 trend analysis, nmonitoring of the level and rate ofchange over operating time of measured paramete
24、rs.4. Summary of Practice4.1 An inductive sensor is fitted either in-line with, or in abypass loop of, the lubricant flow. The sensor locations andconnection method chosen will depend on the individualinstallation but should supply a representative portion of the oilflow and debris from the gearbox
25、or drivetrain through thesensor before any filtration. The minimum requirements of asystem are the detection and counting of ferrous and non-ferrous metallic wear debris carried in the oil flow. Counts areoften accumulated in one or more material channels for binnedsize ranges. Bin size ranges can b
26、e configurable, as are thenumber of bins. Example options are one to five bins, spanningthe range from an equivalent sphere diameter (ESD) of 40 mto greater than 1000 m in the case of ferromagnetic debris, orfrom 135 m to greater than 1000 m for non-ferromagneticdebris. Bins can be extended to as ma
27、ny as 20 for finergranularity and precision in particle size or mass estimates. Theupper size limits are determined by signal saturation of theparticular sensors. Estimates of cumulated debris counts and/ormass may also be calculated as a function of time. Correlationof the rate of change of accumul
28、ated counts and/or massprovides information on the health of the machinery and can beused to inform planning decisions on maintenance schedules orestimate remaining useful life (RUL).5. Significance and Use5.1 This practice is intended for the application of online,full-flow, or slip-stream sampling
29、 of wear debris via inductivesensors for gearbox and drivetrain applications.5.2 Periodic sampling and analysis of lubricants have longbeen used as a means to determine overall machinery health.The implementation of smaller oil filter pore sizes for machin-ery has reduced the effectiveness of sample
30、d oil analysis fordetermining abnormal wear prior to severe damage. Inaddition, sampled oil analysis for equipment that is remote orotherwise difficult to monitor or access is not always sufficientor practical. For these machinery systems, in-line wear debrissensors can be very useful to provide rea
31、l-time and near-real-time condition monitoring data.5.3 Online inductive debris sensors have demonstrated thecapability to detect and quantify both ferromagnetic andnon-ferromagnetic metallic wear debris (1, 2). These sensorsrecord metallic wear debris according to size, count, and type(ferromagneti
32、c or non-ferromagnetic). Sensors can be fitted tovirtually any lubricating system. The sensors are particularlyeffective for the protection of rolling element bearings andgears in critical machine applications. Bearings are key ele-ments in machines since their failure often leads to significantseco
33、ndary damage that can adversely affect safety, operationalavailability, operational/maintenance costs, or combinationsthereof.5.4 The key advantage of online metallic debris sensors isthe ability to detect early bearing and gear damage and toquantify the severity of damage and rate of progression to
34、wardfailure. Sensor capabilities are summarized as follows:5.4.1 Can detect both ferromagnetic and non-ferromagneticmetallic wear debris.5.4.2 Can detect 95 % or more of metallic wear debrisabove some minimum particle size threshold.5.4.3 Can count and size wear debris detected.5.4.4 Can provide tot
35、al mass loss.D7917 142NOTE 1Mass is an inferred value which assumes the debris isspherical and made of a specific grade of steel.5.4.5 Can provide algorithms for RUL warnings and limits.5.5 Fig. 1 (5) presents a widely used diagram to describe theprogress of metallic wear debris release from normal
36、tocatastrophic failure. This figure summarizes metallic weardebris observations from all the different wear modes that canrange from polishing, rubbing, abrasion, adhesion, grinding,scoring, pitting, spalling, and so forth. As mentioned innumerous references (6-12), the predominant failure mode ofro
37、lling element bearings is spalling or macro pitting. When abearing spalls, the contact stresses increase and cause morefatigue cracks to form within the bearing subsurface material.The propagation of existing subsurface cracks and creation ofnew subsurface cracks causes ongoing deterioration of them
38、aterial that causes it to become a roughened contact surfaceas illustrated in Fig. 2. This deterioration process produceslarge numbers of metallic wear debris with a typical size rangefrom 40 m to 1000 m or greater. Thus, rotating machines,such as wind turbine gearboxes, which contain rolling elemen
39、tbearings and gears made from hard steel, tend to produce thiskind of large metallic wear debris that eventually leads tofailure of the machines.5.6 Online wear debris monitoring provides a more reliableand timely indication of bearing distress for a number ofreasons.5.6.1 Firstly, bearing failures
40、on rotating machines tend tooccur as events often without sufficient warning and could bemissed by means of only periodic inspections or data samplingobservations.5.6.2 Secondly, because larger wear metallic debris particlesare being detected, there is a lower probability of falseindication from the
41、 normal rubbing wear that will be associatedwith smaller particles. And because wear metal debris particlesare larger than the filter media, detections are time correlated towear events and not obscured by unfiltered small particles.5.6.3 Thirdly, build or residual debris, from manufacturingor maint
42、enance actions, can be differentiated from actualdamage debris because the cumulative debris counts recordeddue to the former tend to decrease, while those due to the lattertend to increase.5.6.4 Fourthly, bearing failure tests have shown that weardebris size distribution is independent of bearing s
43、ize (2, 3, 6,12, 13).6. Interferences6.1 In order to avoid wear debris counts being invalid due topossible noise from drivetrain application environmental influ-ences such as excessive vibration and loads, unusually highelectromagnetic interferences, abnormally low oiltemperatures, and unusual oil p
44、ressure pulsations, users shouldselect a sensor having specifications that can cope with theirpossible environmental influences and have it installed and setto work in accordance with the sensor manufacturers recom-mendations.7. Apparatus7.1 Inductive wear debris sensors incorporate a magneticcoil a
45、ssembly surrounding a non-magnetic tube through whicheither full or partial oil flow from the machinery or equipmentis passed. The coil assembly concept consists of one or moresensing and excitation coils and is the heart of the sensor asshown in Fig. 3. The outer excitation coils establish analtern
46、ating magnetic field and the inner sense coils respond tothe disturbance of this alternating current magnetic field due tothe passage of a metallic debris particle. As the mechanism bywhich the metallic particle interacts with the magnetic field isdifferent in the two material classes, magnetic susc
47、eptibility inFIG. 1 Wear Debris CharacterizationFIG. 2 Typical Bearing SpallFIG. 3 Sensor Major ComponentsD7917 143the case of ferrous debris and electrical conductivity (eddycurrents) in the case of non-ferrous debris, an inherent reversalin the signal phase provides clear discrimination (Fig. 4).
48、It isimportant to note, however, that some single channel inductivewear debris sensors detect a reversal in signal amplitude ordirection to identify non-ferrous as opposed to monitoringphase angle between output channels.7.1.1 Moreover, the size of the signal is related to acharacteristic “size” of
49、the particle diameter in the case ofnearly spherical debris and an equivalent spherical diameter inthe case of other morphologies, allowing binning and classifi-cation to be readily reported. There are orientation effects in thecase of highly asymmetric particles on the signal size and,likewise, the precise material composition can also influencesignal magnitude by some degree. Nevertheless, such sensorsare able to provide accurate and consistent real-time diagnosticinformation to monitor critical gearbox and drivetrain systems.7.2 Sensor Positioning:7.2
