Tes wawancara Rotating equipment Engineer.pdf

5/25/2018 Tes wawancara Rotating equipment Engineer.pdf

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ROTATI NG EQUI PMENT ENGI NEER

28 J AWABAN

SOAL TESWAWANCARA

by:

Ei ra Patri ansyah Ari efrotati ngengi neer@gmai l . comhttp: / / rotati ngengi neer. bl ogspot. com


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28 J awaban Soal Tes Wawancar a by ei r a 2

Pengantar

Assal amu al ai kumwr. Wb.

e- book 28 J awaban Tes Wawancara i ni di maksudkan untuk membantu

para peserta tes sel eksi Rotati ng Equi pment Engi neer. Namun, e-

book i ni dapat j uga bermanfaat bagi para mahasi swa Tekni k Mesi nti ngkat akhi r yang i ngi n mempersi apkan di ri nya sej ak di ni untuk

memasuki duni a kerj a berprofesi sebagai Rotati ng Equi pment

Engi neer. Pi hak-pi hak sel ai n dari pada dua gol ongan di atas

dapat pul a menggunakannya untuk menambah i l munya ataumemanfaatkannya untuk menyel esai kan suatu tugas.

Soal - soal i ni benar-benar di ambi l dari soal tes masuk sebagai

Rotati ng Equi pment Engi neer yang sebenarnya pada suatu

perusahaan mi gas di Ti mur Tengah. Penul i s berusaha membuatj awabannya dari berbagai l i teratur.

Soal dan (sebagi an) j awabannya sengaj a penul i s tul i s dal am

bahasa I nggri s di karenakan bahasa I nggri s merupakan kemampuanyang sangat mendasar yang harus di mi l i ki ol eh seorang Rotati ng

Equi pment Engi neer. J uga wawancara tes sel eksi Rotati ng

Equi pment Engi neer hampi r 100% di l akukan dalambahasa I nggri s.

Penul i s harapkan e- book i ni dapat membantu dal ammenghadapi tes

wawancara dan memberi kan seki l as gambaran mengenai ketrampi l andasar yang harus di mi l i ki ol eh seorang Rotati ng Equi pment.

Ti dak ada gadi ng yang ti dak retak, penul i s mohon maaf j i ka ada

kekurangan dal am penul i san dan penul i s dengan senang hati

meneri ma kri ti k dan saran. Korespondensi dapat di ki ri mkan ke:

rotati ngengi neer@gmai l . com.

Depok

Dzul qai dah 1428 H

November 2007


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1. St at e any 3 r easons f or not pumpi ng ofpl unger ( r eci pr ocat i ng) pump

Excessi ve suct i on l i f t , not enough suct i on pr essur e above

vapor pressur e, ai r i n l i qui d, Suct i on str ai ner / f i l t er

bl ocked, no l i qui d suppl y, br oken val ve spr i ng, val ves st uckopen, bypass val ve l eaki ng, wor n val ves, l eaki ng, pump not

r ot at e due t o br oken coupl i ng or bel t .

2. Dr aw si mpl e sket ch of back t o back ar r angement of angul arcont act bal l bear i ng

not e t hat wi de l i p of

out er r i ngs ar e mat ed


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3. St at e 5 r easons f or mechani cal seal f ai l ur e1. mi shandl i ng ( di r t y, chi pped, scrat ched, ni cked, or ot her

damages dur i ng assembl y)

2. I ncor r ect seal assembl y3. I ncor r ect seal sel ect i on/ wr ong appl i cat i on.4. I mpr oper st ar t up.5. I nadequat e i nst r ument at i on, t ubi ng, and cont r ol syst em.6. Fl ui d cont ami nat i on.7. Poor equi pment condi t i on. Excessi ve shaf t r unout ,

def l ect i on, vi brat i on.8. Wornout seal . Compl et ed l i f et i me.

4. Name some of t he seal f l ushi ng pl ans i n API and dr aw a l i nedi agr am of any t wo of t hose

a. I nt egr al ( i nt er nal ) r eci r cul at i on f r om pump di schar ge t oseal . Pl an 1


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b. Reci r cul at i on f r om pump case t hr ough cycl one separat ordel i ver i ng cl ean f l ui d t hr ough cool er t o seal and f l ui dt r ough cool er t o seal and f l ui d wi t h sol i ds back t o pump

suct i on. Pl an 31

c. Pl an 32, i nj ect i on t o seal f r om ext er nal sour ce of cl eanf l ui d.

d.

Pl an 2, Dead-ended seal chamber wi t h no ci r cul at i on off l ushed f l ui d.

e. Pl an 11, r eci r cul at i on f r om pump di schar ge t hr ough a f l owcont r ol or i f i ce, when necessar y, t o t he seal . The f l ow

ent er s the seal chamber adj acent t o t he mechani cal sealf aces, f l ushes t he f aces and f l ows acr oss t he seal back

i nt o the pump.

f . Pl an 21, Reci r cul at i on f r om pump di schar ge t hr ough a f l owcont r ol or i f i ce, when necessary, and a cool er and i nt ot he seal chamber .

g. Pl an 41, r eci r cul at i on f r om pump di schar ge t hr ough anor i f i ce, when necessar y, t o a cycl one separ at ordel i ver i ng t he cl ean f l ui d t o t he seal chamber . Thesol i ds ar e del i ver ed t o t he pump suct i on l i ne.

5. What i s t he purpose of pumpi ng r i ng?Pr ovi de an easi l y and economi cal l y r enewabl e l eakage j oi ntbet ween pump i mpel l er and pump casi ng.


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6. What i s vi br at i on? St ate uni t of measurement of t he sameVi br at i on i s per i odi c back- and- f or t h mot i on of t he par t i cl es

of an el ast i c body or medi um. I t i s usual l y a r esul t of t he

di spl acement of a body f r om an equi l i br i um condi t i on,

f ol l owed by the body' s r esponse to t he f or ces t hat t end t or est or e equi l i br i um. Free vi br at i ons occur when a syst em i s

di st ur bed but i mmedi at el y al l owed t o move wi t hout r est r ai nt ,

as when a wei ght suspended by a spr i ng i s pul l ed down andt hen rel eased. For ced vi br at i ons occur when a syst em i s

cont i nuousl y dr i ven by an exter nal sour ce.

Di spl acement [ mi l s peak t o peak]

Vel oci t y [ i nch per second r ms/ peak]Accel er at i on [ g peak]

7. How do you i dent i f y a l eak i n a dr y gas seal and st ate 3r easons f or dr y gas seal f ai l ur e

Normal l y onl y 0. 3 3 f t 3/ mi n. Above t hat means l eaki ng. Worn

f ace, wor n l abyr i nt h, weak spr i ng.

8. Ment i on any 3 pr oper t y of a l ubr i cantVi scosi t y, pour poi nt , f l ash poi nt , col or , speci f i c gravi t y,

vi scosi t y i ndex.

9. What i s oi l wedge?Hydr odynami c f or ce cr eat ed by l ube oi l due t o shaf t r ot at es

t hat suppor t s t he shaf t and r el ocat es i t wi t hi n j our nalbear i ng cl ear ances. Hydr odynami c

pr i nci pl es, whi ch ar e act i ve as t he

shaf t r ot at es, cr eat e an oi l wedge

t hat suppor t s t he shaf t and r el ocat esi t wi t hi n t he bear i ng cl ear ances. I n

a hor i zont al l y spl i t bear i ng t he oi l

wedge wi l l l i f t and suppor t t heshaf t , r el ocat i ng t he cent er l i nesl i ght l y up and t o one si de i nt o a

nor mal at t i t ude posi t i on i n a l ower

quadr ant of t he bear i ng. The normal

at t i t ude angl e wi l l depend upon t heshaf t r ot at i on di r ect i on wi t h a cl ockwi se r ot at i on havi ng an

Lat t i t ude angl e

Oi l

Wedge

Bear i ng CL

ournal

CL


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at t i t ude angl e i n t he l ower l ef t quadr ant . Ext er nal

i nf l uences, such as hydr aul i c vol ut e pr essures i n pumps orgener at or el ect r i cal l oad can pr oduce addi t i onal r el ocat i ng

f or ces on t he shaf t at t i t ude angl e and cent er l i ne posi t i on.

10. Dr aw gener al appear ance of per f or mance curve of acent r i f ugal compr essor .

11. Dr aw gener al appear ance of per f or mance curve of acent r i f ugal pump.

Per hat i kan bahwa f l owr at e semaki n t i nggi maka head pompa

( TDH) akan t urun/ semaki n r endah. NPSHR akan semaki n t i nggisei r i ng dengan meni ngkatnya f l owr at e pompa. Ef i si ensi pompat i dak t erus menerus nai k dengan meni ngkatnya f l owr at e, akan

t et api memi l i ki suat u ni l ai opt i mum, Best Ef f i ci ency Poi nt

( BEP) . Ber i kut i ni adal ah t ypi cal kur va cent r i f ugal pump I SO

st yl e dan US st yl e.

I sent ropi c

head

f l owr at e

ef f i ci encySur ge

Speed 1

Speed 2

Speed 3

f l owr at e

Ef f i ci encyTDH

BHP

GP

NPSHR


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12. What i s st at i c and dynami c unbal ance?St at i c unbal ance = one pl ane unbal ance. Exi st when t wounbal ance wei ght s l i ne up wi t h each ot her ( i n- phase

unbal ance wei ght s) .

Dynami c unbal ance = t he unbal ance wei ght s are nei t her 0o

apar t as wi t h st at i c unbal ance, nor ar e t hey 180o apar t aswi t h coupl e unbal ance. Thi s unbal ance t ype i s t he most common

unbal ance f ound i n t he f i el d. Thi s i s combi nat i on of st at i c

and coupl e ( 180o apart unbal ance wei ght s) unbal ance.


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13. What are the saf et y pr ecaut i ons t o be take bef ore begi nni ngj ob i n a hydr ocar bon f aci l i t y?Know what t o do and how t o do t hat , Task r i sk assessment and

work permi t appr oval

14. Expl ai n sur ge and st al l !Sur ge = condi t i on of f l ui d f l ow t hr u ai r f oi l t hat becomet ur bul ence due t o excessi ve angl e of at t ack. St al l = unst abl e

condi t i on due t o excessi ve sur ge.

15. How t o check l abyr i nt h cl ear ance f or a bar r el compr essor ?I nboar d and out boar d bear i ng l i f t up measurement ( di amet r al

cl ear ance) , and end pl ay check ( axi al cl ear ance) .

16. How do you cent r e a cent r i f ugal compr essor r ot or?Dur i ng r ot or assembl y t her e i s a pr ocess j acki ng/ t ensi oni ng

r ot or st udshaf t . Then dur i ng i nst al l at i on t her e i s a checki ngof bear i ng cl ear ance ( axi al [ endpl ay] and r adi al [ l i f t up] )between af t and f orward bear i ng.

17. What i s pol yt r ophi c head?The Pol yt r opi c Head i s an express i on used f or dynami ccompr essors t o denote t he f oot - pounds of work r equi r ed per

pound of gas. A Pol yt r opi c Pr ocess i s def i ned i n

Ther modynami cs as an i nt er nal l y r eversi bl e process, whi ch

conf or ms t o t he r el at i on PVn = Const ant .

18. How t o check over speed t r i p ( OST) i n a smal l st eam t ur bi ne?Mani pul at e t he gover nor , movi ng the st em/ l ever i n and out

manual l y sever al t ur ns on t he hand wheel .

19. How t o set nozzl e cl ear ance i n a st eam t ur bi ne?Cl ean casi ng and nozzl e r i ng seal i ng sur f ace. Appl y a t hi n

coat of past e t ype seal er and pl ast i c st r i ng compound t o

t he nozzl e r i ng seal i ng sur f ace on t he st eam end t ur bi necasi ng. Appl y ant i - gal l i ng compound t o t he t hr eads of t he

nozzl e r i ng bol t s. Bol t t he nozzl e r i ng t o t he t ur bi ne

casi ng. Be sur e t hat l ockwasher s ar e used wi t h al l bol t s.Pl ace l ockwasher s on t he rever si ng bl ade assembl y bol t s andappl y ant i - gal l i ng compound t o t he bol t s t hr eads. Put t he

bol t s t hr ough t he hol es i n t he rever si ng bl ade assembl y and

sl i p t he spacer s over t he bol t s. Posi t i on t he r ever si ng

bl ade assy i n t he t ur bi ne casi ng and bol t i t t o t he nozzl er i ng. Ret ur n t he r ot or assy t o t he t ur bi ne casi ng.


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20. What i s TTV?St at e i t s f unct i onTr i p and Throt t l e Val ve. To cont r ol st eam t urbi ne speed by

cont r ol l i ng t he amount of st eam go i nt o st eam t ur bi ne. I t

i s a saf et y devi ces.

21. What i s a governor ? and St at e some t ypes of gover norEqui pment t o mai ntai n engi ne speed.

I soc = mai nt ai n engi ne at const ant speed but var i abl e l oad.

anddr oop = const ant l oad, var i abl e speed.

22. Name some of t he i nt er nat i onal st andar d of st eam t ur bi ne.a. API 611- Gener al Pur pose St eam Tur bi nes.b. API 612- Speci al Pur pose St eam Tur bi nes.c. ASTM D 4248- St andard Pract i ce f or Desi gn of St eam Tur bi ne

Gener ator Oi l Syst ems.

23. What i s bump cl ear ance at r eci pr ocat i ng compr essor ? How t omeasur e and set ?

Bump cl ear ance = di st ance bet ween pi st on head and i nner wal l

of cyl i nder headMeasur ed by open val ve housi ng, put t i n wi r e, r otat e

cr ankshaf t unt i l pi st on move t o TDC or BDC. Rot etae backward

t he cr ankshaf t so we can pul l out t he t i n wi r e. Measur e the

t hi ckness of t hi n wi r e ( t hi ckness = bump cl ear ance) . Set i t

by r ot at e t he l ocknut at pi st on r od and cr osshead.

24. How t o check r od def l ect i on i n r eci pr ocat i ng compr essor ?Posi t i on t wo di al i ndi cat or s st em agai nst pi st on r od cl ose t o

packi ng case. Set i ndi cat or t o zer o wi t h t he pi st on t owar dcr ankend. Readi ng ar e t o be t aken i n ver t i cal and hor i zont al

di r ect i on. Bar crankshaf t . Measur e t he r eadi ng of di al

i ndi cat or whi l e pi st on at mi d st r oke and at t he head end.

25. What i s t i p cl earance Aer i al f an cool er and how t o measur e?Di st ance bet ween t i p end of f an cool er bl ade and i t ci r cul ar

guar d/ cover. Usi ng T di al gage. Or , i f t he bl ade i s bi genough so cur vat ur e er r or can be negl ect ed, we can use f i l l ergage.

26. Gener al l y what shal l be t he f i ta) Bet ween i nner r ace of ant i f r i ct i on bear i ng and pump shaf t ?

I nt er f erence f i t


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b) Bet ween out er r ace of t he bear i ng and housi ng? Press f i t

c) Bet ween coupl i ng and shaf t of a cent r i f ugal pump? Wr i ngi ngf i t

27. Wr i t e sequent i al act i vi t i es- st ep i nvol ve i n bear i ngr epl acement on a si mpl e back pul l out pump

Remove coupl i ng spacer and coupl i ng nut . Tap pump hal fcoupl i ng of f i t s t aper ed seat . Unbol t bear i ng housi ng. Remove

cap scr ews bet ween bear i ng housi ng and end cap and l oosen

socket head scr ews i n def l ect or s. Sl i de def l ect or and end capagai nst sl eeve nut . Li f t oi l r i ng over oi l r i ng col l ar t o

cl ear housi ng. Sl i de bear i ng housi ng of f bear i ngs. Remove i n

sequence: oi l r i ng, bear i ng l ock nut , bear i ng l ockwasher , oi l

r i ng col l ar , bal l bear i ng, oi l r i ng, oi l r i ng col l ar . Sl i deend cap and def l ect or f rom shaf t . I nstal l at i on: s l i de

def l ect or s on shaf t agai nst sl eeve l ocknut . Sl i de end cap

over shaf t agai nst def l ect ors. I nstal l oi l r i ng col l ars ( f ort hr ust bear i ng) , oi l r i ng, oi l r i ng col l ar , bear i ng l ockwasher , bear i ng l ock nut , and oi l r i ng. Pl ace gasket over

i nboard end cap and push bear i ng housi ng over bear i ng (be

car ef ul wi t h oi l r i ngs) . I nser t dowel and bol t i nt o pl ace.

Br i ng i nboar d end cap f orward and t i ght en cap sr ews. Wi t houtpl aci ng gasket , sl i de out boar d housi ng over bear i ng, br i ng

endcap f orwar d and t i ght en cap scr ews bet ween endcap and

housi ng f i nger t i ght . Measur e gap bet ween housi ng and endcap

and r emove bear i ng housi ng f r om bear i ng. I nser t gasket wi t h

t hi ckness of 0. 003 gr eat er t han measur ed gap. Push bear i nghousi ng over bear i ngs, i nser t dowel s and bol t i nt o pl ace.

Br i ng out boar d end cap f orward and t i ght en cap scr ews. Check

shaf t assy f or endpl ay. Shoul d be 0. 002. Sl i de def l ect or

i nt o pl ace and l ock t o shaf t wi t h socket head set scr ews.Rot at e shaf t t o check t hat i t i s f r ee t o r ot at e and does not

bi nd.

28. I n at 3rd st age r eci pr ocat i ng compr essor , 2nd st age pr essur e i shi gh, what coul d be pr obl em and how you wi l l r ect i f y?

I t i s caused by f l ow f r om 2nd st age t o 3rd st age bl ocked, t hen

pr essure bui l d up at 2nd st age.And i t can be due t o ei t her s: 3rd st g suct i on val vebl ocked/ st uck, or 3rd st g pi st on r i ng br oken, or 2nd stg

di schar ge val ve bl ocked/ st uck, or i nt er cool er bet ween 2nd st g

and 3rd st g bl ocked. I t can be ver i f i ed by measur i ng 3rd st ge

suct i on and di schar ge pr essur e and t emper at ur e, and


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compr essor over al l gas f l ow r at e ( check i f t her e i s any gas

f l ow r educti on) .

Documents

Tes wawancara Rotating equipment Engineer.pdf