87

EMA Learn

VA

MAIning Publica

ARIABL

IL Tation from

LE SPE

TIP Full Spectr

EED O

PS rum Diagno

OPERAT

ostics

TION o

Vol

of EQU

. 87 Septem

UIPMEN

mber 2012

NT

EMVolu New

The curPaper oa close

Print

1. Sele 2. Sele 3. Sele Email Tand be as 1, 2,

This

Variabland Vib

Displac

A New

A New Review

MAme 87

White P

rrent Email Ton the Vibra-up view of t

ting This

ect the “Prin

ect “Print Pu

ect “Save Fi

Tip will DownReady for P

, 3.

Month’sle Speed Opbration Cha

cement Res

Vendor Ap

Rolling Elew

AIL TSeptem

Papers A

Tips library ition Analysisthe Table its

s Email

nt” Icon

ublication”

ile” and “OK

nload as a PPrinting. Eas

s Featurperation of aracteristics

sponse with

plication Re

ement Beari

TIPmber 201

Available

ncludes a Ws Periodic Tself.

Tip

”

PDF sy

res: Centrifuga

s

h Speed

eview

ing Pocket

PS 2

e

White able and

l Pumps

Guide

4

2012CORE ASN ISO

CONC

SPEC

Ano

The cconbinperformradial Handbpump ratios volute green high-flconditi

2 TraininE TRAININGNT: Intro (IVO: Cat I, C

CENTRATED• TWF –

IALTY & AD• ODS/M• On-site

other Loo

chart on thenation of mance curv

load cuvbook”. The

specific sand impellesystems.

to red as thow conditioions.

ng Sche SERIES: VA) – VAI –

Cat II, Cat III,

D TRAININGSpectrum –

DVANCED TModal – Prece Mentoring

ok at the

e cover wasgeneric

ves super-imves courtee load curvepeeds, imp

er/casing widThe added

he pump apons and rec

edules

VAII – VAIII, Cat IV

G TRACK: – Phase – Be

TRAINING cision Balanc

e Cover

s constructecentrifuga

mposed withsy of “Thes show vapeller/casingdth ratios fod colors exproaches cacirculation a

I

earings

cing

:

ed from a al pump h empirical he Pump ariations in g diameter or standard xtend from avitation at at low-flow

Pump

The Vsignificseveradrives efficienworld. drawbaVFD’s.

Amongproblemfrom EcurrentbearingAmplif

Figure 1

Figure 2

p Vibratio

Variable Fcant in-roadal years. Sp

has been ancy and veThere are

acks to co.

g the mms are rolElectro-Erot seeks a g racewfication fr

1.0 REB Flutin

2.0 Natural Fr

on & VFD

Frequency ds into indpeed controa key compersatility in

however, ontrolling

most comling elemeosion or path to g

ways, arom residu

ng in a VFD C

requency Amp

’s

Drive hadustry overol of inductiponent in in

the manuseveral opthese mot

mmonly dnt bearing “Fluting”

ground throand Resual unbalan

applied much frequencyThese although importantbeen dat len

npublicatio

Controlled Mo

plification from

as made r the last on motor ncreased

ufacturing perational tors with

discussed damage

as stray ough the sonance nce now

over a broader

y range. topics,

very t have

discussed gth in

numerous ons.

otor

m VFD’s

SomeelevatforcesThis squarunbala2 (ormeasuare reitself. bearinfunctiomeanbearinsignifi

Figur

Electrthat pmotorthat 2at 12determfreque(readoshouldfaults Passincan bfaults

e of the lested vibratios in the rot

response red” affectance amplir squaredured as vibeacted as This can

ng life, beinon of appls that if th

ng expectcantly

re 3.0 Unbala

rically, the provide ther health arex Line Freq

20 Hz. mine theency fromout) prior d appear indevelop (

ng, etc.). e slightly care not di

sser discuson amplitudtor as the

is knownt. If spetude is incr). The

bration on tincreased become a ng that theied load ine bearing ted Life

nce is Propor

2x Line Fr vibration unchanged

quency is nNow the

e operatim the mo

to calculatn the measuSlip, Pole This is not

confusing. ifferent from

ssed issuedes from cspeed is i

n as the ed is doureased by a

additionalhe bearingload in theproblem of

e L10 Life in the beariload is doucan be

rtional to Spe

requency sanalyst clud, except foow not a fianalyst m

ng (syncotor controting the peurement spPassing, R

t a difficult Again, not

m a non-V

es include centrifugal ncreased.

“speed-ubled, the a power of “forces” housings e bearing f sufficient s a cubic ing. This ubled, the

reduced

eed Squared

signatures ues to the or the fact ixed value must first chronous) ol center eaks that ectrum as Rotor Bar

task, but e that the

VFD motor

but the signatures will vary with the control frequency.

Some lesser-discussed issues on the driven side of the machine are also introduced with variable frequency drives and the associated variable speed control. When the motor drives a centrifugal pump, a compressor, a fan or a blower several performance problems may result. In a pump operated at “low-flow” conditions recirculation can occur. In pumps operated at very high-flow conditions, cavitation may result. Both problems are erosion inducing problems. The pump is designed with parameter known as the “Best Efficiency Point” (BEP). The VFD operating speed has an influence on how much variation exists away from the desired BEP.

In VFD driven fans, similar performance issues exist. Variations in speed can influence stable operation resulting in problems such as Stall, Rotating Stall, and fan Surge.

Some extended problems related to the earlier mentioned Resonance Amplification include the Critical Speed class of problems. Resonance typically implies excitation of a static or non-rotating natural frequency structure. A Critical Speed is defined as an excitation of a rotor (rotating) natural frequency. Operating at a Critical Speed is especially problematic, in that, sensitive clearances in bearings and seals can be eliminated by the rotor deflections. A typical result is rotor-stator rub, rotor instabilities and possibly bent shafts and rotors.

Some other specialized problems known as “Roll Chatter” or “Roll Barring” can occur in paper machine press rolls, textile calendar systems, and sheet metal forming applications when operating speeds are increased into resonant ranges of the equipment. When residual unbalance forces are increased with elevated speed operation, driving forces of sufficient energy are created to excite structural natural frequencies. In these cases roll damage can be the result.

Figure 4.0 Centrifugal Pump Design Curve Alarms

Figure 5.0 Fan & Blower Design Curves

Figure 6.0 Roll Barring / Roll Chatter Issues

Displacement Limits

The Table (below) is constructed as a severity guideline for Fluid Film Journal type bearings. The displacement severity profiles are not a function of machine type as normally presented in vibration trending with a velocity parameter. Rather the critical displacement levels are closely associated with bearing internal clearances. An operating displacement level in excess of 50% of the bearing diametrical clearance indicates a fast approaching instability threshold. The displacement amplitude parameter varies with speed, thus in the table below greater permissible amplitudes are found at lower speeds. The allowable amplitudes are reduced as speed is increased. An equivalent (seismic) velocity (inches per second) level is presented in the table left hand column for a severity reference. The more commonly circulated Rathbone Chart for Displacement is found to the right. This chart shows the variations of amplitude with frequency, again note the trend of greater allowable amplitudes as frequency (rotor speed) is reduced.

ProduCommwww.Co Full Spea Beta diagnosAnalyzeinclude:

The latefull blowintuitive or tutorifull-featuPhase, easily tras a preas a Unaccess not perfeis abundand engof firmw The appthis yeapackagedirectly. Full Spectbooks, pathis newsopinions o

uct Reviemtest Instru

ommtest.com

ectrum DiagnoTest group

stic applicationer unit. The

Rotor BalancOrbit PlottingBump TestinCoast-down /Cross-channLong Time WTime Synchr

est addition town Experimen

firmware appng to get up ured and incluReal, Imagin

ransferred to e-formatted siversal File Fto ME’scope ect, thus the dantly apparegineering was

ware diagnosti

plication is schar. Sometimees. For mo

trum Diagnosticsapers, reference sletter. All of thof Full Spectrum

ews: ments Ltd.

m

ostics was refor a new ans in the 4-c

current vb8

cing g ng

/ Run-up nel Phase Waveform ronous Averag

o the existing ntal Modal Aplication requto speed. Thude all FRF p

nary, and Cohthe vb8 Asc

series of plotsFormat (UFF)

for animationreasoning be

ent that consids applied. It ic applications

heduled to bees big things rore informati

s has no financiamaterials, or a

he reviews of thDiagnostics’ ana

equested to baddition to thhannel Comm

8 firmware ap

ging

set of applicAnalysis platfired minimal he graphic disparameters (Mherence). Thcent databases, and can befile for those

n. No, the apphind a “beta” derable upfros a nice fit fos.

e ready for rereally do comon contact

al connection witpplication notes

hese materials aalysts and instruc

e a part of e suite of mtest vb8 pplications

ations is a form. The instruction splays are

Magnitude, he data is e software e exported who have

plication is test, but it

ont thought or the suite

lease later me in small

Commtest

th any of the reviewed in

are first-hand ctors.

LiterReliabwww.R Full Sppocketb120 pa “RollinIdentifis nowSpectru This punomencontambackgrof pracdesign corpora There abearingand pra The ghandlinwww.Rphone

rature Revbility SolutiReliabilitySol

pectrum Diagbook publicage 3.5 x 6.0 i

ng Elemenfication and w available aum Diagnosti

ublication is pclature, de

mination and ound of the actical experie

engineer fation.

are a lot of pug manufactureactical aspect

uides retail ng. More ReliabilitySolut

at 218-729-4

views: ions lutions.us

gnostics formation from Rench spiral bo

nt BearinVibration A

at the Reliabcs websites.

packed with iesign and vibration failuauthor, Tomaence in the pfor a large

ublications proers, but nonets in a single

for $19.95 information

tions.us and 646 and 612-

mally announeliability Soluund guide title

gs: Failurnalysis Poc

bility Solution

information frfits to

ure modes. as Brown, incpaper industry

bearing ma

ovided by roll that merge thconcise guide

each plus n can be

www.fullspec-875-9959, re

nces a new utions. The ed:

re Mode cket Guide” ns and Full

rom bearing lubrication,

The unique cludes years y and as a anufacturing

ling element he technical e.

postage & found at

c.net, or by espectively.

REMAINING: 2012 CORE VIBRATION TRAINING SCHEDULE IMPLEMENTING A SUCCESSFUL PdM PROGRAM IN-PLANT COURSES AVAILABLE Tuition: $ 945.00 / 2-day Format Proficiency Test: Included INTRODUCTION TO VIBRATION ANALYSIS IN-PLANT COURSES AVAILABLE Tuition: $ 945.00 / 2-day Format Proficiency Test: Included VIBRATION ANALYSIS I DEC 11-14 Charlotte, NC 2012-VA1-05 DEC 18-21 New Orleans, LA 2012-VA1-06 Tuition: $ 1,295.00 / 3-day Format Certification Exam: $ 200.00 VIBRATION ANLAYSIS II SEP 25-28 Cedar Rapids, IA 2012-VA2-06 Tuition: $ 1,395.00 / 3-day Format Certification Exam: $ 200.00 VIBRATION ANALYSIS IIIa IN-PLANT COURSES AVAILABLE Tuition: $ 1,595.00 / 4-day Format Certification Exam: $ 200.00 PRACTICAL VIBREATION ANALYSIS IIIb IN-PLANT COURSES AVAILABLE Tuition: $ 1,595.00 / 4-day Format Certification Exam: $ 200.00

REMAINING: 2012 SPECIALTY VIBRATION TRAINING SCHEDULE MODAL & ODS ANALYSIS 2 IN-PLANT COURSES AVAILABLE For In-Plant Training: ModalGuy@aol.com Tuition: $ 1,595.00 / 3-day Format One Month ME’scope Software Included CONC TIME WAVEFORM ANLAYSIS NOV 27-28 Chillicothe, OH 2012-TWF-02 Tuition: $ 945.00 / 2-day Format Proficiency Test: Included CONCENTRATED SPECTRUM ANALYSIS

OCT 02-03 St. Paul, MN 2012-CSA-03

Tuition: $ 945.00 / 2-day Format Proficiency Test: Included CONCENTRATED PHASE ANALYSIS IN-PLANT COURSES AVAILABLE Tuition: $ 945.00 / 2-day Format Hands-on Exercises: Included CONCENTRATED RE BEARING & GEAR ANLAYSIS OCT 16-17 Cedar Rapids, IA 2012-BGA-01 Tuition: $ 945.00 / 2-day Format Proficiency Test: Included VIBRATION ANALYSIS FOR MOTOR SHOPS DEC 04-06 St. Paul, MN 2012-VAM-02 Tuition: $ 1,295.00 / 3-day Format Hands-on Exercises: Included PRECISION BALANCING !!! NEW !!! NOV 13-14 Wheeling, WV 2012-BAL-04 Tuition: $ 945.00 / 2-day Format Hands-on Exercises: Included

THE V

The Vibindispewell as analyst

Some 4and defeasily f

GUÍA

Este mcompilareferenMantenCondicespecty reglaaproximpueden

Tambiéespecifdefinicidefinicisuficienla bolsacontenconsideesenciaCondic

THE V

The Vib108-pagInformaspecificinclude

If you lieducatiAnalys Order n Or by P

BULK

VIBRATIO

bration Faultnsable assea helpful too

t and his ma

45 Rotating fined. Convfits in your po

A DE FAL

manual constado por Full

ncia rápida pnimiento Preción. La guíaros, formas sde análisis

madamente n presentar e

én incluimosficaciones dión de bandaiones de Prontemente pea de su camido es tan gerado como al para la ind

ción.

VIBRATIO

bration Anage pocket si

ation on dozecations and dd.

ked the Vibrional step sh

sis Techniqu

now at: httpPhone @ (7

K DISCOUNA

ON FAUL

t Guide is a et for every vol to bridge tnagement s

Machinery Fveniently desocket for eve

LAS DE V

ta de 110 páSpectrum D

para la indusedictivo y Moa incluye ejede onda, de de fase parunos 45 proen maquinar

s varios estáe vibración, as de alarmaocesamientoequeño como

misa ( 3.5” X rande que una guía de

dustria del M

ON TECH

alysis Technized informaens of analydata present

ration Faulthould be theues Guide g

p://www.fulls63) 577-995

NTS & BUNAVAILABL

LT GUIDE

110-page vibration anathe gap betwtaff.

Faults are Idsigned at 3” xeryday use!

VIBRACIÓ

áginas y fue Diagnostics cstria de onitoreo de emplos de efiniciones dera oblemas queria rotativa.

ndares de guías para as, fórmulas

o de Señaleso para llevar6.0”), pero spodría ser

e referencia Monitoreo de

HNIQUES

niques Guidation treasureysis techniqutation forma

t Guide, you Vibration get yours no

pec.net/store59

NDLE PACLE!

E

alyst, as ween the

entified x 6”, it

ÓN

como

e fallos

e se

s y s. Es rlo en su

e

GUIDE

de is a e trove.

ues, ts are

ur next

ow at:

e.html

KAGES

THE The VoveramacheffectWhenanalys Order Or by BU P

VIBRATI

Vibration Anall Alarm chainery faults.ively allow th

n combined sis loop. We

r now at: Htty Phone @ (

ULK DISCACKAGE

ION ANA

alysis Wall Carts in the . The faulthe analyst towith the Vib

eather you r

tp://www.full763) 577-99

COUNTS &ES AVAIL

LYSIS W

Chart is a 46center of tht groupings o “narrow-dobration Faurequire one c

lspec.net/sto959

& BUNDLLABLE!

WALL CHA

6” x 36” Fullhe chart are

include freown” the potlt Guide, thechart or a ne

ore.html

LE

ART

-Color Lamie surroundeequency contential sourcee Vibration eed to wall-p

nated Refered by groupntent and des and zeroAnalysis W

paper your o

rence for youpings of ovedominant dir-in on curren

Wall Chart coffice, we can

ur drab officer 40 dominrectional resnt vibration pompletes then help!

ce wall. Theant rotatingsponse thatproblem. e diagnostic

e g t

c

TH This“quicand case Thisby Fvibrameaclas IndivGuidGuidAna Get BUAV

E VIBRAT

s Full Color Lck-look” metsuggests D

e and make

s Chart is a “Frequency Cation sourceasurement dsify faults ac

vidual Faultsde for a morde is valuab

alysis Perio

yours now a

LK DISCVAILABLE

TION ANA

Laminated 1thod of distiniagnostic Tthe call!

“Logical” anaContent and es are instanata. The Taccordingly.

s are Foot Nre detailed reble, your nexdic Table!

at: www.full

OUNTS &E!

ALYSIS P

3 x 17 inch nguishing on

Tests or form

alysis tool thDirectional R

ntly reduced able “forces”

ote Refereneview. If yoxt educationa

lspec.net, o

& BUNDL

PERIODIC

card-stock tne machinermula that ma

hat classifiesResponse. Tbased on ththe user to

nced to the Vu think the Val step shou

or by phone a

LE PACKA

C TABLE

able providery fault from ay be used t

s vibration prThe potentia

he analyst’s cthink logical

Vibration FaVibration Fauld be the Vib

at 763-577-9

AGES

es a another to build a

roblems al current lly and

ault ault bration

9959

INSTRUCTORS:

Full Spectrum Diagnostics’ Lead Instructor & Seminar Author is Dan Ambre. Dan is a graduate of The University of Iowa with a Bachelor’s degree in Mechanical Engineering, and has completed additional graduate level course work in Engineering Dynamics from The University of Illinois at Chicago, and Florida Atlantic University. Dan is a Certified Vibration Analysis Level III Instructor (Category IV) with over 16 years of Vibration Training and Certification Experience.

Dan’s 25+ years of vibration experience in the Aviation & Aerospace Industries comes from positions at Sundstrand Aviation Corporation and Pratt & Whitney (United Technologies Corporation). This fieldwork includes Vibration & Acoustic testing, Rotor Dynamics analysis of high speed Rotor Systems, Experimental Modal, and Finite Element Analysis.

His consulting experience base comes from positions at Technical Associates and Full Spectrum Diagnostics, which he founded in June of 2000. He is a Registered Professional Engineer in the States of North Carolina and Minnesota.

Dan can be contacted by phone at (612) 875-9959, or via Email at ModalGuy@aol.com

ModalGuy@aol.com

In 2004, after years of close association, Louis G. Pagliaro joined Full Spectrum Diagnostics. Lou fulfills multiple roles as our Seminar Sales Coordinator, Senior Instructor and course content co-author. Lou is a certified Level III Vibration Analyst (since 1996) and was recently re-certified by American Society of Nondestructive Testing as an ASNT PdM Level III in Vibration Analysis (Category IV). He has over 30 years of varied industrial experience, including Maintenance Management, Vibration Analysis, Vibration Training, Certification, and course development in areas of Noise Control, Precision Maintenance, Precision Alignment, Preventive Maintenance, and Maintenance Skills Enhancement. His worldwide teaching credentials include instruction of TAC, Update International, CSI, Entek and SKF customers in eight countries. Louis is a graduate of Niagara College in Welland, Canada. Lou can be contacted by phone at (704) 577-3953, or via Email at Lpagl@aol.com.

LpagL@aol.com