Georgia Southern University Department of Mechanical Engineering
Professor: Dr. alentin Soloiu
!A"LE #$ %#&!E&!S
1) Intro Introdu ducti ction on 2) Key Ter Terms ms 3) Back Backgr grou ound nd a. Balance b. Alig Alignm nmen entt 4) Use of of i!tu i!turla rlaser ser "#$ "#$ a. $b%e $b%ect cti& i&e e b. 'afety c. Intr Introd oduc ucti tion on d. (o (ou unting ing e. roce rocedur dure e of Alignmen Alignmentt rogr rogram am *) +omen +omencla clatur ture e ,) -efer eferen ence ces s
'&!(#DU%!'#& In ractically e&ery mac/inery0 all t/e necessary stes taken to ensure uality of t/e material0 t/e surface nis/0 and recision in tolerance0 can mean not/ing if comonents are not balanced and aligned it/in t/e limits of t/e articular alication. Unbalanced0 rotating arts roduce centrifugal force0 creating e!cessi&e &ibration. (ac/inery it/ misaligned s/afts creates rotat rotatio ion n outsi outside de its collin collinear ear a!is0 a!is0 causin causing g t/e rotat rotation ion to becom become e t/ree t/ree dimensional. Unbalanced andor misaligned arts lead to remature failure in bearings0 coulings0 seals0 and t/e s/aft t/emsel&es. T/e ob%ecti&e for t/is lab is to instruct /o to do a roer s/aft alignment in order to re&ent all t/e t/e cons conse eue uenc nces es t/at t/at come come from from a misa misali lign gnme ment nt.. 5ase 5aserr alig alignm nmen entt euime euiment nt from from #ibrali #ibralign gn ill be used to facilita facilitate te t/is rocedur rocedure. e. 5aser 5aser alignment /as o&ertaken t/e industry due to its deendability and faster nature comared to traditional s/aft alignment0 /ic/ consisted of using dial gauges and /and calculations. )E* !E(MS (otor6 An electrically dri&en oer unit. '/af '/aft6 t6 A long long smoot smoot/7s /7sur urfac faced ed iece iece of metal metal it/ it/ a circul circular ar cross cross section. um6 A de&ice for mo&ing liuid or gas by decreasing or increasing t/e ressure on it. -otor6 A small rotating ca7like unit at t/e end of t/e distributor s/aft. 8ouling6 A connecting de&ice used beteen to ob%ects so motion of one ill be imarted to t/e ot/er9 it may be mec/anical0 /ydraulic0 or electrical. Alignment6 t/e ractice of aligning to or more s/afts it/ eac/ ot/er to it/in a tolerated margin. :uasi7static6 /aening so sloly as to aear to be static.
"A%)G(#U&D Unbalanced arts /a&e an une&en distribution of mass rotating about its centerline. T/e une&en distribution of mass may be due to t/e material;s orosity0 &oids0 and ot/er imerfections. '/aft misalignment can occur due to oor oor insta installa llatio tion n ract ractice ices0 s0 found foundati ation on settle settlemen ment0 t0 and and loose looseni ning ng of /ardare. cie e>ciency ncy and and redu reduce ce energy consumtion. To minimi=e maintenance cost and dontime0 condition moni monito tori ring ng of t/e t/e mac/ mac/in iner ery y s/ou s/ould ld be in lac lace e in addi additi tion on to init initia iall installa installatio tion n correc correction tions0 s0 suc/ as balanci balancing. ng. redi redicti& cti&e e mainten maintenance ance is t/e analysi analysis s of en&iron en&ironmen mentt and conditio conditions ns of t/e oeratin oerating g mac/iner mac/inery y. 'uc/ 'uc/ analysis can be done by monitoring &ibration0 /ic/ can indicate bearing ear and s/aft alignment.
BA5A+8" An unbalanced unbalanced rotor is t/e une&en distribution distribution of its mass. Ideally0 a balanced system /as its mass concentration and t/e center of rotation ?8$-) eual to eac/ ot/er as muc/ as ossible. As t/e rotor sins in a mac/ine0 a centrifugal force is e!erted. T/e folloing euation reresents t/e force6 F =mε ω
2
?1)
igure 1 dislays t/e centrifugal force due to center of gra&ity acting outard from t/e geometrical center.
$igure +. %ross sectional vie, of an unbalance- rotor
T/e force causes t/e comonents comonents to undergo undergo stress as t/e articles e!tend out and aay from t/e 8$-. An unbalanced system may be due to t/e material material;s ;s non7uni non7unifor form m density density structur structure0 e0 nis/ nis/ surface surface and toleran tolerance ce uality0 symmetry0 and distortion during oeration suc/ as t/ermal grot/. T/e folloing gure is an e!aggerated e!aggerated image of before before and after a turbine blade undergoing centrifugal force.
$igure . "efore /soli-0 an- after /-ashe-0 e1ect of centrifugal force on a turbine bla-e
T/ere are t/ree rimary tyes of unbalanced unbalanced conditions6 conditions6 static0 coule0 and dynamic. 'tatic unbalance unbalance refers to a condition condition t/at is caused by a oint mass at some distance aay from t/e 8$-. T/e rincial a!is of inertia ?AI) is o@set o@set and and aral arallel lel to t/e 8$8$-.. T/is T/is condi conditio tion n is corre correcte cted d by addi adding ng eig/ts to counter t/e unbalance. T/is situation is ideal for rotating arts0 suc/ as a y/eel0 it/ most of t/eir mass concentrated around one lane. AI
8$-
$igure 2. %orrecting static unbalance ,here M is the mass of the ,heel3 r is the ra-ius3 an- m is the a--e- mass. T/e unbalance unbalance ?U) can be found using t/e folloing relations/i6 U = mr
?2)
T/e secic unbalance unbalance ? u) is found using "uation ?3)6 u=
mr M
?3)
8oule unbalance unbalance refers to an eual unbalance unbalance t/at are 1CD aart and at oos osit ite e ends ends of t/e t/e rotor otor.. To cor correct ect t/e t/e unba unbala lanc nce0 e0 &ibr &ibrat atio ion n measurements must be taken /ile t/e rotor is sinning and masses are added in to lanes.
$igure 4. %orrecting couple unbalance at t,o planes
Eyna Eynami mic c unba unbala lanc nce e may may be rod roduc uced ed by an a!ia a!iall loca locati tio on of t/e t/e unbalanced mass on t/e rotor. It can occur on t/e rotor or in t/e case of uasi7static unbalance0 /ic/ is a subset of dynamic unbalance0 occur on a comonent suc/ as a couling. T/e AI and t/e 8$- do not coincide.
$igure 5. %orrecting -ynamic unbalance by a--ing ,eights that are not -iametrically -iametrically oppose- an- correcting 6uasi7static unbalance by a--ing ,eight to an unbalance- coupling.
A5IF+("+T It is tyically desired for t/e s/afts to rotate about a collinear a!is. T/e collinear a!is is t/e 8$- of to s/afts0 /ic/ is not t/e same as t/e 8$- of eac/ indi&idual s/aft. In most cases0 it is imossible for bot/ t/e s/afts to s/are t/e e!act same 8$-. Eeending on t/e alication0 a certain degree of misal misalign ignme ment nt is acce accetab table le or reui reuire red. d. T/er T/ere e are are t/ree t/ree tyes tyes of s/aft s/aft misalignment.
$igure 8. Shaft alignment
T/e rocess rocess of aligning a s/aft eit/er during installation or for correction correction reui reuire res s measu measurin ring g t/e osit ositio ion n at se&er se&eral al locat locatio ions ns along along t/e s/aft s/aft in refer eferen ence ce to t/e t/e syst system em;s ;s 8$ 8$-. Tradi raditi tion onal ally ly00 t/e t/e roc roces ess s as as time time consuming0 as t/e measurements ere taken manually it/ dial indicators. Any Any misa misali lign gnme ment nt as as t/en t/en cor correcte ected d it/ it/ /and /and calc calcul ulat atio ions ns.. 5ase 5aserr tec/nology /as enabled t/e s/aft alignment rocess to be comleted it/ /ig/er accuracy and at a faster rate. Tyically it/in a system0 t/e dri&ing com comon onen entt is cons consid ider ered ed as t/e t/e mo&e mo&eab able le elem elemen ent0 t0 and and t/e t/e dri& dri&en en como comone nent nt is consi consider dered ed as t/e statio stationa nary ry elemen element. t. T/e T/e locat locatio ion n of t/e refe eferenc ence oi oint must be deter termined ined00 /i /ic/ is t/e t/e lane of oer transmission. Fenerally0 t/is is at t/e center of t/e couling. T/e mo&eable element must be aligned to t/e stationary element by adding or remo&ing s/ims s/ims for &ertic &ertical al ad%ust ad%ustme ments nts00 and and mo&in mo&ing g t/e eleme element nt side7t side7to7s o7side ide by utli=ing %ackscres for /ori=ontal ad%ustments. BA8K5A'G Backl Backlas/ as/ is t/e unint unintend ended ed mo&em mo&ement ent t/at t/at occur occurs s /en /en rotat rotatin ing g t/e s/afts during an alignment rocess. It can cause errors in measurement and non7reeatable readings. To control backlas/0 s/aft s/ould be rotated in t/e direct direction ion of rotat rotatio ion n duri during ng mac/in mac/ine e oera oeratio tion. n. T/e T/e coul coulin ing g s/oul s/ould d be reloaded before =eroing by keeing t/e couling /alf of t/e s/aft on t/e mo&a mo&abl ble e mac/ mac/in ine e in t/e t/e lead lead..
$BH"8TI#"
'tudent must rite a tec/nical reort folloing t/e comletion of t/e e!eriment. T/e lab reort must include6 an introduction of t/e e!eriment ?background) along it/ dening keyords0 rocedure0 and stes taken during t/e e!eriment0 tables of any data taken0 discussion of results0 a conclusion /ere results are stated0 and an abstract. Be sure to include any error t/at mig/t /a&e occurred during t/e e!eriment. 'A"T Eo not disassemble0 modify or use t/e euiment in ot/er ays t/an e!lained in t/e oerating instructions. 8lass 2 is considered safe for its intended use it/ only minor recautions reuired. T/ese are6 • •
+e&er stare directly into t/e laser transmitter. +e&er s/ine t/e laser directly into anyone else;s eyes.
I+T-$EU8TI$+ '/aft alignment6 Eetermine and ad%ust t/e relati&e osition of to mac/ines t/at are connected0 suc/ as a motor and a um0 so t/at t/e rotational centers of t/e s/afts are collinear0 /en t/e mac/ines are orking in a normal oerating condition. 8orrection of /ori=ontal s/aft alignment is done by mo&ing t/e front and t/e rear air of one mac/ine;s feet0 &ertically and /ori=ontally0 until t/e s/afts are aligned it/in t/e gi&en tolerances. A tolerance table is a&ailable in t/e system. T/e tolerances are not standardi=ed but are utili=ed it/in #ibralign. T/e i!turlaser i!turlaser "#$ system /as /as to measuring measuring units t/at t/at are laced laced on eac/ s/aft by using t/e !tures sulied it/ t/e system. After rotating t/e s/afts into di@erent measuring ositions t/e system calculates t/e relati&e distance beteen t/e to s/afts in to lanes. T/e distances beteen t/e to measuring lanes0 distance to t/e couling and distances to t/e mac/ine feet are entered into t/e system. T/e dislay bo! t/en s/os t/e actual alignment condition toget/er it/ t/e osition of t/e feet. Ad%ustment of t/e mac/ine can be made directly0 according to t/e dislayed &alues. ($U+TI+F T/e sensor mark marked ed J( s/ould be mounted mounted on t/e mo&able mo&able mac/ine mac/ine and t/e sensor marked J' on t/e stationary mac/ine. T/e block are marked it/ an ' and ( to indicate /ere t/e sensors are laced. T/e sensors s/all
be assembled on t/eir #7block !ture0 and laced on eac/ side of t/e couling. Gold t/e #7block !ture urig/t and mount it on t/e s/afts of t/e measurement ob%ect ?igure L).
$igure . Positioning of Sensor.
5ift t/e oen end of t/e c/ain ?igure )0 tension it so t/at t/e slack is remo&ed and attac/ it to t/e /ook.
$igure ;. Securing the sensor.
irmly tig/ten t/e c/ain it/ t/e tensioning scre ?igure M). If necessary0 use t/e sulied tensioning tool. Eo not o&er tig/ten. If t/e s/aft diameter is too large t/e c/ains can be e!tended it/ e!tension c/ains.
$igure < !ensioning Scre,
Ad%ust t/e /eig/t of t/e sensor by sliding it on t/e osts until a line of sig/t is obtained for bot/ lasers ?igure 1C). 'ecure its osition by locking bot/ claming de&ices on t/e back of bot/ units.
$igure += Sensor A->ustment an- po,er button
T/e laser of of t/e (7sensor can can be ad%usted ad%usted it/ t/e ad%ustment ad%ustment scre on t/e to of t/e unit. T/ere is normally no need to ad%ust t/e laser0 but t/is mig/t be necessary /en measuring at long distances.
-$8"EU-" $ A5IF+("+T -$F-A( 1) Turn on t/e monitor monitor and ait for t/e rogram rogram to boot u. Also turn on t/e sensors. 2) 'tart t/e alignment alignment rogram rogram by touc/ing t/e Gori=ontal Gori=ontal '/aft Alignment icon in t/e (ain (enu. T/e Trioint met/od ill be used for a arameter setting of MCC rm.
TriointN TriointN met/od met/od In t/e Trioint met/od0 t/e alignment condition can be calculated by taking t/ree oints /ile rotating t/e s/aft at least ,CD. In t/is met/od all oints are taken manually.
$igure ++ Shaft Alignment )it
"nter dimensions
$igure + !ouch button to start logging measurements.
3) T/e screen screen dislays dislays t/e mo&able mo&able mac/ine. mac/ine. T/e tra>c lig/ts lig/ts s/o green /en t/e laser /its t/e detector. 'elect dimension bo!es to enter dimensions ?igure 12). 4) (easure (easure and enter dimensions dimensions using t/e tae tae measure measure ro&ided ro&ided ?igure 13).
$igure +2 Measuring -istance bet,een sensors
*) ou must enter t/e t/e distance beteen beteen t/e sensors0 and t/e t/e distance beteen t/e center of t/e couling and t/e (7sensor. ?If you only is/ to c/eck s/aft alignment0 t/ese are t/e only necessary distances).
$igure +4 Measuring -istance for the motor feet
,) T/e distance distance beteen t/e t/e (7sensor and and t/e rst air air of feet and t/e distance beteen t/e rst and t/e second airs of feet can be entered no or later ?t/ese distances are necessary to ro&ide t/e feet &alues). ?igure 14) (easurement oint registration
$igure +5 !ouch icon for ?rst rea-ing
L) 'et t/e sensors at aro aro!imately !imately t/e same same rotational rotational angle at t/e rst rst measurement osition. Touc/ t/e register icon. T/is registers t/e rst reading.
$igure +8 (otate shaft to,ar-s green area
) -otate -otate t/e s/afts to t/e ne!t ne!t osition ?igur ?igure e 1,). Use t/e side /eels to /el it/ t/e rotation of t/e s/aft. T/e s/afts must be rotated o&er a minimum of 4*D. Freen sector s/o ermitted ositions. -ed sector s/o forbidden ositions. T/e -egister icon is not s/on if t/e rotation is less t/an 4*D.
$igure + !ouch icon for secon- rea-ing
M) Touc/ t/e register register icon. T/is registers registers t/e second reading. reading. -otate -otate t/e s/afts to t/e t/ird osition.
$igure +; Move shaft to last position in green area
1C) 1C) Touc/ ouc/ t/e t/e reg regis iste terr ico icon. n. T/is T/is regis egiste ters rs t/e t/e t/i t/irrd rea readi ding ng..
(easurement results
$igure +< %orrections that nee- to be -one for alignment
T/e (easuremen (easurementt -esult -esult screen s/os couling couling &alues &alues and foot &alues &alues in bot/ t/e &ertical and /ori=ontal direction. T/e symbol to t/e left of t/e
couling &alues indicates t/e angular direction and o@set0 and also if t/e &alues are it/in tolerance.
$ut of double tolerance ?red and in&erted).
T/e mac/ine mac/ine icture icture itself also indicates indicates t/e couling couling alignment. alignment. "&aluating t/e result T/e angle angle and o@set o@set &alues are are used to determine determine t/e t/e alignment alignment uality. T/ese &alues &alues are comar comared ed it/ t/e alignmen alignmentt tolerances to determine determine /et/er correction is necessary. If suitable tolerances are selected in t/e tolerance table0 t/e symbols described abo&e indicate if t/e angle and o@set &alues are it/in tolerance or not. T/e foot &alues indicate t/e mo&able mac/ine;s foot ositions /ere corrections can be made. 11) Fo to '/imm imming by tou touc/in /ing t/e t/e s/i s/im icon con and t/e t/e rogram ill s/o t/e otion of /o many s/ims /a&e to be allocated to balance t/e s/aft. T/e s/ims are to be inserted /ere t/e t/reads of t/e knobs are located on t/e attac/ed late ?igure 21). '/ims are already found belo t/e lates to ro&ide an easier access to t/e inserting t/e additional s/ims reuired belo. It is not recommended to remo&e t/e e!isting laced s/ims. Use t/e s/ims in an orderly manner. 5oosen t/e knobs before inserting s/ims and be sure lace t/inner s/ims beteen t/icker s/ims for easier lacement.
$igure = Program sho,ing the shim length to be a--e- in inches
$igure + Presentation an- positioning of shims
Alignment 12) 12) If t/e t/e mac mac/i /ine ne /as /as bee been n ad% ad%us uste ted d &er &erti tica call lly y in in t/e t/e s/im s/immi ming ng screen0 go directly to alignment in t/e /ori=ontal direction. If t/e mac/ine /as not been ad%usted in t/e s/imming screen0 alignment in t/e &ertical direction /as to be done rst. ?It is safe to ski t/e s/imming screen as if a mistake is made0 corrections can be made by obser&ing t/e li&e alignment /ic/ ill ro&ide feedback suc/ as if backlas/ is taking lace.)
$igure Live vertical alignment /si-e7vie,0
13) 13) -otat otate e t/e t/e s/af s/afts ts to t/e t/e 12 12 or or , o;cl o;clo ock osi ositi tion on to mak make ad%ustments in t/e &ertical direction. T/e angle guide /els you to reac/ t/e rig/t osition. Ad%ust t/e mac/ine &ertically until t/e &alues for bot/ angular and arallel alignment are it/in tolerance ?igure 22). T/e arros at t/e feet s/o in /ic/ direction t/e mac/ine s/all be mo&ed.
$igure 2 Live @oriontal alignment /top7vie,0
14) 14) -otat otate e t/e t/e s/af s/afts ts to t/e t/e 3 or M o;cl o;clo ock osit ositio ion n to mak make ad%ustments in t/e /ori=ontal direction. T/e angle guide /els you to reac/ t/e rig/t osition. Ad%ust t/e mac/ine /ori=ontally until t/e &alues for bot/ angular and arallel alignment are it/in tolerance ?igure 23). T/e arros at t/e feet s/o in /ic/ direction t/e mac/ine s/all be mo&ed. Be careful it/ maniulating t/e s/aft because any sudden mo&ements ill cause angular misalignment and more corrections ill /a&e to be carried out.
$igure 4 Shaft Aligne- /,ithin tolerance0
If not gi&en enoug/ tension0 t/e s/aft ill not /old t/e sensor at t/e 3 o;clock osition so be sure to /old t/e s/aft at t/e couling to re&ent t/e sensor from /itting t/e table.
$igure 5 @ol-ing the shaft to prevent bacBlash an- sensors moving -o,n
1*) 1*) -otat otate e t/e t/e s/af s/afts ts back back to t/e t/e 12 12 o;c o;clo lock ck osi ositi tio on and and c/ec c/eck k t/a t/att t/e mac/ine is still it/in tolerance. Alignment is no comleted. To conrm t/e result0 re7do t/e measurement. 1,) -e7 measure.
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