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EM MAIIL TIP T PS A Learn ning Publicaation from Full Spectrrum Diagno ostics
Vo ol. 82 March h 2012
Whe en Ro olling g Elem mentt Bea arings s Fail
Tra ainin ng Op ptions s Exp pand ded with w Co oncen ntrated Cours C ses
EMAIL TIPS Volume 82 March 2012
A New Look You may have noticed a new look to the Email Tips publication. We hope you like it! The hope is that Full Spectrum Diagnostics can add some real world insights into machinery maintenance and vibration analysis through a more visual format. The magazine format is provided by Issuu.com. It is our goal to promote sharing of ideas and solutions through our training side of the business and offer a view from the trenches via the field engineering and diagnostics side of the business. The publication of the February Issue of Email Tips prompted several useful responses. Mostly, the comments focused on being able to access Issuu.com on company servers, problems with SPAM filters, downloading, and printing the colorfilled format (not very ink friendly…). To address these issues, the current publication and future issues will be distributed in multiple formats. The articles will be included in the body of the email for easy black & white printing. A PDF attachment to the email should enable an easy digital download. Finally, the Issuu.com link will be included for the heavily “on-line” readers. I expect some additional distribution problems, but hopefully the most important aspect, the access to useful information will prevail. As always, your comments are welcome!
Dan Ambre [ModalGuy@aol.com] (763) 577-9959 www.fullspec.net
Features: The Time Waveform – The Beat Frequency Phenomena in the Time Waveform The Spectrum – The Peak-Hold Averaging Methods in the detection of Resonance in the Operating Speed Range Definitions: Operating Deflection Shape Analysis of Foundations and Fastened Joints – A Visual Interpretation 2012 Training Schedules Core Training Courses: • Intro (IVA) – VAI – VAII – VAIII Concentrated Training Courses: • TWF – Spectrum – Phase – Bearings Specialty Training Courses: • ODS/Modal – Precision Balancing
Cover: The cover features a large SKF 29434E cylindrical roller bearing photographed during replacement following a rapid onset of failure. The physically indirect measurement path to this bearing required a more detailed review of the vibration data and historic trends to eventually make the case to pull the unit (vertical pump application). The photo is interesting due to the angle and back lighting which reveals the rolling element’s bumpy ride on the raceway. The failure was traced to improper loading (brinelling) during the installation operations. The vertical pump system was operated for nearly two years before the unit was pulled. The backup unit has been operating for eight years without issues.
Time e Domain n Tips: A beat frequency often results s from two (or more) machin nes rotating at relative ely the sam me speed. One co ommon application is in belt driven machines with a sheave s ratio of nearly [1.0 : 1.0]. The vib bration respo onse of each h machine in ndividually may be b acceptab ble, but a summation of their amplitu ude responses may occ cur where a “beat” or pulsatio on is felt in adjacent a stru uctures at a frequency f equal to o the difference in the tw wo operating g speeds. This pu ulsation coulld be an exc citation sourrce, but is not gen nerally a ressonant respo onse in the structure, but rath her a “forced response””. The sum mmation of energy or beating g effect oc ccurs when the two sourcess’ phase ressponse add (in-phase) or o subtract (out-of--phase) inducing an n amplifica ation (or attenua ation) of ove erall energy in the mach hine. The signatu ure is very obvious o if measured m as a Time Wavefo orm, assum ming that prroper collecction time duration ns are speciified. Mathem matically, the e Beat Frequ uency is defiined as: TBEAT = [60 / ∆RPM M]
or
TBEAT = [1 / ∆H Hz] B Th he Beat Freq quency Phen nomena: Tim me & Freque ency
Frequency Domain D Tips: T Most data d collecction platforrms include e several “Averag ging” metho ods that ca an be emp ployed in measurrement captture. One of o these is th he “PeakHold” average. a Peak-H Hold Averaging techniqu ues can be a simple method d of resonan nce detectio on, especiallly for the more frrequent app plications off Variable Frequency F Drive machinery. m T range of The o operating speeds in VFD equipment has both h advantag ges and disadva antages. On n the disadvantage side of things, many VFD V systemss will force th he rotating machinery m to trave erse and am mplify natural frequencies in the operatin ng speed ra ange of the drive. d Manyy of these potentia al resonance e amplifications can be avoided if they ca an be identified. The Pe eak Hold an nalysis contiinuously sam mples the data and retains the highes st amplitude e spectral (peak) information until the me easurement is halted. By man nually “swee eping” the fre equency drivve through its norm mal operating range a spectral s sign nature can be collected. Rem member nattural freque encies are directio onal, so it is advisa able to perform an indepen ndent Peak-Hold sw weep in th he axial, horizon ntal, and verttical axes. Pe eak-Hold Avveraging Shu utdown Tran nsient Sweep p
Definitions & Nomenclature: ODS Analysis of Foundations In mechanical systems and machinery applications the vibration levels from the driving sources in the machine are significantly attenuated across fastened connections and critical joints when attached properly, or as designed. Excessive vibration response occurs when resonant amplification or mechanical looseness exists or is transmitted across the fastened joints. In rotating equipment, the vibration response is typically measured at the bearing housings (for rolling element type bearings) or at the rotor (as measured on fluid film type journal bearings). Elevated vibration levels can be related to numerous machinery malfunctions via vibration frequency analysis. Since the rotor itself is the source of the machine vibration, the amplitudes should be greatest at the bearing cap or rotor measurement locations. When the machine or structure is mapped with multiple measurements, as in Operating Deflection Shape (ODS) analysis, the transmission of that vibration energy can be evaluated. As the machine response is measured at locations further away from the rotor, the energy (vibration amplitude) should diminish. When problematic mounting conditions exist, an excessive synchronous or harmonic vibration signature will result. The first indication of a fault is expected at the machine bearing or rotor locations, where the fault may be amplified. When the malfunction is related to the foundations or mounting location(s), the vibration levels will still show an attenuation effect (at the mounts) but will exceed the typical “foundation-level” response. The overall machine response will include a lifting of the unit, usually in the vertical direction. For taller structures with higher centers of gravity an elevated horizontal “rocking” response may result. The ODS type analysis creates a visual assessment of the machinery which is exposed via computer animations. The measurement map should include numerous samples across the joints or connected (grouted) interfaces. The key response of a malfunction in a foundation typically shows a relative out-of-phase motion across the joint interfaces. As noted above, the energy in the machine will not diminish as would be expected, rather the overall machine motion may include a vertical lift or a horizontal rocking response in the structure. This “visual” evaluation is very effective when determining root cause failure in rotating machinery applications, or pin-pointing a source.
Motor “Rocking” on Faulty Mounting Frame
Grout Line Separation in Motor Mount
2012 CORE VIBRATION TRAINING SCHEDULE
2012 SPECIALTY VIBRATION TRAINING SCHEDULE
IMPLEMENTING A SUCCESSFUL PdM PROGRAM
MODAL & ODS ANALYSIS 2
JUN 19-20 Cameron, WI 2012-PdM-01
MAR 20-22 Davenport, IA 2012-ODS-01 JUL 24-26 St. Paul, MN 2012-ODS-02
Tuition: $ 945.00 / 2-day Format Proficiency Test: Included
INTRODUCTION TO VIBRATION ANALYSIS FEB 21-22 FEB 28-29 MAR 13-14 APR 17-18
St. Paul, MN Harrisburg, PA Brookfield, WI Knoxville, TN
2012-INT-01 2012-INT-02 2012-INT-03 2012-INT-04
Tuition: $ 945.00 / 2-day Format Proficiency Test: Included
St. Paul, MN Cedar Rapids, IA Wheeling, WV Chicago, IL Charlotte, NC New Orleans, LA
CONC TIME WAVEFORM ANLAYSIS JUN 05-06 Cedar Rapids, IA 2012-TWF-01 NOV 27-28 Chillicothe, OH 2012-TWF-02 Tuition: $ 945.00 / 2-day Format Proficiency Test: Included
CONCENTRATED SPECTRUM ANALYSIS
VIBRATION ANALYSIS I MAR 06-09 APR 10-13 APR 24-27 SEP 11-14 DEC 11-14 DEC 18-21
For In-Plant Training: ModalGuy@aol.com Tuition: $ 1,595.00 / 3-day Format One Month ME’scope Software Included
2012-VA1-01 2012-VA1-02 2012-VA1-03 2012-VA1-04 2012-VA1-05 2012-VA1-06
Tuition: $ 1,295.00 / 3-day Format Certification Exam: $ 200.00
JUN 26-27 Brookfield, WI 2012-CSA-01 JUL 17-18 Davenport, IA 2012-CSA-02 OCT 02-03 St. Paul, MN 2012-CSA-03 Tuition: $ 945.00 / 2-day Format Proficiency Test: Included
CONCENTRATED PHASE ANALYSIS SEP 18-19 Davenport, IA 2012-CPA-01 Tuition: $ 945.00 / 2-day Format Hands-on Exercises: Included
VIBRATION ANLAYSIS II MAR 20-23 MAY 08-11 MAY 22-25 JUL 10-13 SEP 25-28
Leesport, PA Chicago, IL Cumming, GA St. Paul, MN Cedar Rapids, IA
2012-VA2-02 2012-VA2-03 2012-VA2-04 2012-VA2-05 2012-VA2-06
CONCENTRATED RE BEARING & GEAR ANLAYSIS OCT 16-17 Cedar Rapids, IA 2012-BGA-01 Tuition: $ 945.00 / 2-day Format Proficiency Test: Included
Tuition: $ 1,395.00 / 3-day Format Certification Exam: $ 200.00
VIBRATION ANALYSIS FOR MOTOR SHOPS
VIBRATION ANALYSIS IIIa OCT 23-26 Leesport, PA 2012-VA3-01
AUG 28-30 Charlotte, NC 2012-VAM-01 DEC 04-06 St. Paul, MN 2012-VAM-02
Tuition: $ 1,595.00 / 4-day Format Certification Exam: $ 200.00
Tuition: $ 1,295.00 / 3-day Format Hands-on Exercises: Included
PRACTICAL VIBREATION ANALYSIS IIIb
PRECISION BALANCING
AUG 21-24 St. Paul, MN 2012-PVA-01
MAY 01-02 Cedar Rapids, IA 2012-BAL-02 AUG 07-08 Brookfield, WI 2012-BAL-03 NOV 13-14 Wheeling, WV 2012-BAL-04
Tuition: $ 1,595.00 / 4-day Format Certification Exam: $ 200.00
Tuition: $ 945.00 / 2-day Format Hands-on Exercises: Included
!!! NEW !!!
THE VIBRATION FAULT GUIDE The Vibration Fault Guide is a 110-page indispensable asset for every vibration analyst, as well as a helpful tool to bridge the gap between the analyst and his management staff. Some 45 Rotating Machinery Faults are Identified and defined. Conveniently sized at 3” x 6”, it easily fits in your pocket for everyday use!
GUÍA DE FALLAS DE VIBRACIÓN Este manual consta de 110 páginas y fue compilado por Full Spectrum Diagnostics como referencia rápida para la industria de Mantenimiento Predictivo y Monitoreo de Condición. La guía incluye ejemplos de espectros, formas de onda, definiciones de fallos y reglasde análisis de fase para aproximadamente unos 45 problemas que se pueden presentar en maquinaria rotativa. También incluimos varios estándares de especificaciones de vibración, guías para definición de bandas de alarmas, fórmulas y definiciones de Procesamiento de Señales. Es suficientemente pequeño como para llevarlo en la bolsa de su camisa ( 3.5” X 6.0”), pero su contenido es tan grande que podría ser considerado como una guía de referencia esencial para la industria del Monitoreo de Condición.
THE VIBRATION TECHNIQUES GUIDE The Vibration Analysis Techniques Guide is a 108-page pocket sized information treasure trove. Information on dozens of analysis techniques, specifications and data presentation formats are included. If you liked the Vibration Fault Guide, your next educational step should be the Vibration Analysis Techniques Guide get yours now at: Order now at: http://www.fullspec.net/store.html Or by Phone @ (763) 577-9959
BULK DISCOUNTS & BUNDLE PACKAGES AVAILABLE!
THE VIBRATIION ANALYSIS WALL W CHA ART This 46” 4 x 36” Fulll-Color Lam minated Vibra ation Analysiis tool is the ultimate com mpanion to the t Vibration n Fault Guide e and the Vib bration Tech hniques Guid de reference es. Over 40 dominant ro otating mach hinery proble ems are outline ed, based on: Fau ult Direction / Amplitude / Frequencyy / Phase an nd Time Wavveform Attrib butes And d categorize ed, based on n: Synchrono ous / Harmonic / Non-Syynchronous AC / DC / Aero-Hydro o and Gearin ng Groupings ore.html Orderr now at: Htttp://www.fulllspec.net/sto Or byy Phone @ (763) 577-99 959
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THE VIBRATION ANALYSIS PERIODIC TABLE This Full Color Laminated 8 ½ x 11 inch card-stock table provides a “quick-look” method of distinguishing one machinery fault from another and suggests Diagnostic Tests or formula that may be used to build a case and make the call! Faults are classified by Frequency Content and grouped in similar patterns: Synchronous / Harmonic / Sub-Harmonic Sub-Synchronous / Non-Synchronous / Modulated (Sidebands) Faults are Color classified Directionally: [ Radial ] / [ Axial ] / [ Radial & Axial ] Faults are Foot Noted to the Vibration Fault Guide for a more detailed reference. If you liked the Vibration Fault Guide, your next educational step should be the Vibration Analysis Periodic Table! Get yours now at: www.fullspec.net, or by phone at 763-577-9959