final intership report.docx

7/24/2019 FINAL INTERSHIP REPORT.docx

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FINAL INTERSHIP REPORT

Executive summary

This fnal internship report included brie history o the company,

organizational structure, work ow, row materials, suppliers and customers,

products, Mission, vision, objectives o the company and overall sections:

spinning section, weaving section and fnishing section! "t also included

di#erent types o machines such as:warping machine, sizing machine,

bleaching machine, $tenter machine, jigger machine, drying and washing

machine, printing machine, calendaring machine etc! including their

operation and unction! This report also include how three phase induction

motor repaired in winding section o the company, machine starting andcontrol mechanisms, boiler room, air compressor and conditioning system,

waste removal system, overall control plant o the company which includes

programmable logic control % relay logic system, and some basic electrical

protective devices such as: sensor, contactor, relay, rectifer, inverter, and

uses! &astly, we include our project and contributions to the company which

ocuses' on winding $ection and an internship e(perience gained which helps

us to improve a lot o skills like )ractical, communication and team playing

skills, also to understand some work eth


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CHAPTER ONE

INTRODUCTION

1.1BAC!ROUND

*ahir +ar Te(tile $hare ompany is vertically integrated te(tile company,

manuacturing -../ cotton products including yarns and abrics! "t was

established in -012 3! rom the und o "talian war reparation in the town o

*ahir +ar, north south o 4ddis 4baba, 3thiopia.5hen the company was

established, there were 167 3thiopian employees o which 76. males and

8.7 emales! The initial capacity o the mills was 8.,... spindles, 76. looms

together with processing plant with the total output o -. million meter

s9uire abric per year! The legal shape o the company was given in May,

-012! 5hen the company was registered as public corporation, in the name

o *ahir +ar te(tile mills $hare ompany with a capital o 3th! *irr 0,620,6..!

4s o $eptember -00., the actory changed rom a public enterprise to share

company and it was fnancially restructured! The name o the ompany isagain *ahir +ar te(tile share ompany and its capital amount at present was

16,.,7;0 3th! *irr! 4ter the leased period, the company's management

made viable two things: structural adjustment and e(pansion and renovation

project, worth o more than 1..million 3th *irr! Most o the e(isting old

machineries such as spinning, weaving and fnishing were replaced by the

integrated +raw


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The business missions o *+T$ are:

)roducing 9uality products o abrics % yarns and being low cost

provider, to be preerred company in domestic and e(port markets

and proftable! *y $atisying customer needs, contribute oreign currency or the

country!

%isi()

The *usiness vision o the ompany is to see being competitive in the

domestic and e(port markets in 9uality % low cost providing o te(tile

products!

O*+ective (, t-e c(ma)y

The main objectives o the actory are:

To manuacture yarn % all kinds o fnished clothes rom cotton!

To produce goods or household use!

To sell its products locally % abroad!

To engage generally in any other trade or business conducive to the

4ttainment o its objectives!

1./ Or0a)iati()a2 Structure (, t-e C(ma)y4n @rganizational structure o *+T$ shows the scope o acceptable

behavior within the company, its line o authority and accountability, and to

some e(tent the organizational relationship with its e(ternal environment!


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Table 1.1 responsibility of organizational structure of BDTSC


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Organizational structure Responsibility

Aeneral manager &eads all over the company activity!


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fnancial sources the company!

Marketing and sale +epFt )lan and budget to the council o general

manager!

4nnouncement o the product o company

4udit % inspection ontrolling the management, fnal applying by

selling% buy

)urchasing % matter $orting di#erent type o output the transport in

selling it

+etermines cost!

Cespecting the customer polling to e(panding

Marketing studying $tudy the 9uality, purchasing prices, marketing

system, and sailing

@ the output!

4nnounce the products o the company or

marketing study place!

Technical manager ontrol the technical problem, solve problem

with their sub division organs

Mechanical % related

5orkshop

reate the work plan, give the responsibility,

control the materials which inter work shop,

+etermines the spare parts in the company

work shop!

3lectrical workshop Made electrical maintenance

Table1.1 responsibility of organizational structure

1.3 4ey sta4e-(25er (, t-e c(ma)y

4ny person or entity interested in a particular business is called a

stakeholder! They are a#ected by the business activity, and they may be part


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o the core decision making team! "nternal and e(ternal stakeholders may

have di#erent interests and priorities, possibly leading to conicts o interest!

"nternal stakeholders are owners, managers, and workers!

3(ternal stakeholders are the customers and the suppliers!

The owner o *+T$ is 3thiopian government itsel and takes about 00/ o

the total shareG thereore the key stake holders o *+T$ are owners and

customers who are the most responsible person in the ompany!

1.6Pr(5ucti() r(cess (, t-e c(ma)y

Pr(5ucts

*ed sheetingH local and e(port=dyed and printed>

4bu ?edi

kuta

yarn on hank

Cust(mer (r e)5 user (, r(5uct

The company supplies its products to the local and e(port markets! The

company produces many products which having di#erent 9uality parameters

based on the customer needs! $ome o the main customers o *+T$ are:

GINAD PLC

FKM PLC

Addis Fana PLC

Sayat PLC

Ambasel Trading House

1.7Raw Material and Accessory suppliers

1.7.1Types of Raw material

The major inputs o production are lint cotton, chemical, and dyestu#s! &intcotton is ound locally which 7;. km away rom the actory site! hemicals %

dyestu#s are imported rom abroad! The inputs are available at any time!

The main ra material used !or "DTSC is #$$% &otton and a&&ording to some do&umented

and oral in!ormation tell us the su''lier o! the main ra material (&otton) is as shon belo *+


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#) Hiot Farm De,elo'ment Com'any

-) Des Pri,ati.ed Limited Share Com'any

/) Abobo Farm De,elo'ment Com'any

0) A!ri&a Pri,ati.ed Limited Share Com'any

1) Abdul2adir Ahmed and Cotton 3esults

4) 3a5a !arm de,elo'ment India

6) Al2ader Ahmed Farm de,elo'ment

The 'ur&hased bale &otton stored to the bale room by identi!ying its 7uality 'arameters8 these

'arameters are tested by the high te&hnology and 9olume Instrument: The tester ma&hine tests

'arameters o! &otton: Su&h as;

Maturity

Fineness

Trash &ontent

1.7." Tyes (, Access(ries a)5 t-eir Su2iers

A&&essories are materials hi&h are used in the &om'any in addition to ra materials to'er!orm a

&om'lete or2 Su&h materials are dye sta< &hemi&als8 greases8 oil8 s'are 'arts and si.ing

ingredients: The 7uality o! te=tile 'ur&hased materials should be !ul>lled the !olloing*

3eliability

Ser,i&eability

Durability

Con!orman&e

A) Sizing Ingredients

Si.ing ingredient materials are used !or si.ing 'ro&ess in ea,ing se&tion o! the &om'any is*

P9A

Mai.e

Arabi& gum

Ma5or Si.e ingredient su''lier


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Asrat ?our !a&tory ("ahir Dar)

@e2unu ("ahir Dar)

B) Chemicals

"DTSC uses many &hemi&al 'rodu&ts !or >nishing 'ro&ess in the 'rodu&tion se&tion: Some o!the

&hemi&als ingredients used !or >nishing 'ro&ess are*

Hydrogen 'er o=ide(H--)

Detergent

'ti&al brightener

Betting agent

hemicals and pigments supplier* Addis Ababa(AA)

C) Spear parts

The !a&tory 'ur&hases many industrial s'ear 'arts !or 'rodu&tion ma&hinery in s'inning8

ea,ing and >nishing se&tions: Thus are;

le&tri&al materials ("elgium E Italy)

P9A E rotary s&reen(Indian E China)


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Chapter 2

!erall Internship "#perience

2$% &'ecti!e of the Internship

2$%$% (eneral &'ecti!e+ebre Markos Iniversity aims that this internshi' 'rogram enables engineeringstudents

under the institute to relate their theoreti&al 2noledge to the real orld: Internshi'sill 'ro,ide

students the o''ortunity to test their interest in a 'arti&ular &areer be!ore 'ermanent &ommitments

are made: Sothat it is more im'ortant be&ause*

The general ob5e&ti,e o! internshi' 'rogram is to de,elo' students in 'ra&ti&al o! the

students theoretical knowledge to get know the interns or2 en,ironment:

Internshi' students ill de,elo' s2ills and te&hni7ues dire&tly a''li&able to their&areers:

Internshi's ill 'ro,ide students ith an in+de'th 2noledge o! the !ormal !un&tional

a&ti,ities o! a Parti&i'ating organi.ation:

Internshi's ill 'ro,ide students the o''ortunity to de,elo' attitudes &ondu&i,e toe


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"." !reeti)0 a)5 %isiti)0 (, t-e C(ma)y

Be ere a''ly an internshi' re7uest 'a'er !or "DTSC in ?IJ3 8..; 3!8 a!ter a month

through a long 'ro&ess e ere sele&ted among thus students ho ha,e a''lied !rom the same

'ur'ose !rom dirst grou' to s'inning

se&tion8 se&ond grou' to ea,ing se&tion ,thirdgrou' to >nishing se&tion%the last group in

garment section: A!ter to ee2sea&h grou' ill rotates and submit a re'ort about or2ing

&onditions8 2noledge gained andre&ommendation !rom ea&h se&tion o! the &om'any:

"./ Overa22 system C(m()e)ts a)5 Oerati() (, t-e C(ma)y

"./.1 8(r4 Secti()s

*ahir +ar te(tile $hare ompany has our sections these are spinning,

weaving , fnishing and Aarment sections! These sections have their own

di#erent machines which perorm di#erent tasks in the production process o

actory!


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"./.1.1 Si))i)0 Secti()

$pinning is manuacturing process or creating polymer fber !it is conversion

o a large 9uantity o individual, unordered fbers o relatively short length

into a linear, ordered product =yarn> o very great length using suitable

machine and devices!

"n *+T$ $pinning section includes cotton processing machines it include

rom bale store to open ending machine or short staple fber ,and or long

staple fber the process includes rom bale store to ring machine!


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ber !ragments and dust 'arti&les

sed to se'arate the tidy or use!ul 'art o! &otton !rom aste 'art


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It !eeds the &lean &otton to the nimi=er ma&hine

ber:

3emo,e dust !rom the >re >lter:

1) nistore Machine

The nistore is used as a storage8 dedu&ting and !eeder ma&hine:

Its main 'ur'ose is to 'ro,ide intermediate storage !or materials in order to ensure trouble+!ree

blo room o'eration:

The integration o! a mesh s&reen >lter inside the nistore eliminates the trans'ort air8 and &reates

an e&ient dedu&ting:

It stores the mi=ed &otton !or reser,e during interru'tion o! ta2ing &otton b uni?o& and trans!er to

&arding as &om'ensation to a,oid any or2 ga' beteen ma&hines:


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) 3aste feeder machine

"n blow room section some useul cotton removed rom di#erent machines

during mi(ing, opening and waste removal process! This useul cotton should

recycle in order to get high productivity in the company production process

so, removed cottons eeds to the waste eeder and it will go through to the

unioc machine path:

;< U)ic()tr(2 mac-i)e

This ma&hine uses the un&ommand hi&h or2s on an ele&troni& basis8 and is a &ombination o!

ni&ontrol ma&hine is used to &ontrol e,ery a&ti,ity o! blo room in the s'inning se&tion: PLCs

and PCS ith a &entral &ontrolling unit: This ma&hine shos the statues o! blo room ma&hine8 an

o'erator &an able to &ontrol all an a&ti,ity in the blo room:

4) .loc5ed clearer roller cleaning machineThis ma&hine is used to &lean roller o! ro,ing ma&hine: In in&reasing the 'rodu&ti,ity o! ro,ing

ma&hine the ?o&2ed roller should be &leaned ith good 7uality:

It &an o'erate easily ith dire&t motor starting me&hanism:

Highly e&ient and !ast &leaning:

Lo 'oer &onsum'tion and noiseless o'eration:

Carding Section

Carding is a me&hani&al 'ro&essing that disentangles8 &leans and intermi=es >ber to 'rodu&e a

&ontinuous eb or sil,er suitable !or subse7uent 'ro&ess: In &ardingma&hines la's are !eedand

sli,ers are re&ei,ed as an end 'rodu&t in &ans or bo=es:

.unction of carding machine

Mi=ing

'ening

Sli,er Formation

limination o! im'urities and dust

In "DTSC &arding se&tion there are to ma&hines !or &arding >ber this are dra !rame ma&hine

and integrated dra !rame ma&hines (IDF):

.unction of /raw .rame Machine

a) 7uali.ing

b) Paralleli.ing


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&) "lending

d) Dusting remo,al

/rawing Section

Draing is a 'ro&ess in hi&h di


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neness is a&hie,ed

Tist the dra!t strand to !orm yarn o! re7uired &ount and strength

Binding the tisted yarn on to the bobbin !or suitable storage8 trans'ortation and !urther

'ro&essing

3inding machine

5inding is the most important operation, which is the creation o large yarn

package that can be easily unwound! The yarn unwound rom package

passes through yarn tensioned and control system, and with the help o a

grooved cylinder, is wound evenly around the packageG the yarn enters the

recess in the cylinder, thus rotary movement o the cylinder corresponds to

the translation o the yarn:

2$,$%$2 3ea!ing Section

5eaving is the interlacing o two sets o yarns, i!e! warp and wet yarns at

right angle to each other! "n *+T$ weaving section includes warping up toinspection machines:


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To ma2e reusable ne=t 'ro&ess

Formation o! suitable 'a&2age !or ar'ing

Che&2ing and &learing the yarn !rom s'inning


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7ooming process

A!ter the re7uired number o! ar' yarns in the !abri&s ound onto the ea,ers beam8 thear'

beam ends are then 'assed through the dro' ires8 the heddles o! the harness !rames and the dent

o! the reed: This a&hie,ed by draing or tying in the &hoi&e de'ending u' on hether or not the

ne ar' is di


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Air +et ica)(2

mac-i)e

S(met :eavi)0

mac-i)eBe!ts mo,ement through

ar' is'neumati&ally

For e!t mo,ement uses

ele&tri&al system

Controlled by 'l&: System ontrolled manually

Not &ontinuously sto'

or2ing

Continuously brea2 its

!un&tion

It is more e&onomi&al "t less economicalIt is

more e&onomi&al

It 'rodu&es relati,ely good7uality &ess 9ualityproduction

Table : di#erence between air jet picanol % somet weaving machine

2$,$%$, .inishing Section

Finishing is the 'ro&ess used in manu!a&turing o! >ber8 !abri&8 or &loth in order to im'art the

re7uired !un&tional 'ro'erties to the >ber or !abri&8 its &ustomary to sub5e&t the material to

di


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/escription of the wor5 flow in finishing section

Inspection machine

Inspection is an iportant aspect followed prior to garent anufacturing to a!oid re"ects due to

fabric #uality and facing with une$pected loss in anufacturing. Its done for fault rate% fabric

construction% fabric weight% shrinkage% color% hand feel% print defect and appearance.

Roller to Batch Machine

This ma&hine is used to &hange the &loth roller that &oming dire&tly in the ins'e&tion ma&hine8

&lothes in the ins'e&tion ma&hine &ut by an o'erators due to a de!e&t on it8 thus &utted &loth rolled

in to bat&h:

*ot 3ashing 8/esizing) Machine

Desi.ing re!ers to the remo,al o! star&hes and si.es !rom the !abri& be!ore the !abri& is set !or

u'&oming 'ro&ess: The insoluble star&h is bro2en don to soluble 'rodu&t hi&h &an be ashed

out: The si.ing material 'resents on the ar' yarns &an a&t as a resist toards dyesand &hemi&al in

te=tile et 'ro&essing: It must be remo,ed be!ore any subse7uent et'ro&essing the !abri&:

+ad:roll Bleach Machine

"lea&hing is a 'ro&ess o! remo,ing all the residual &oloring matter in te=tiles $ "lea&hing ith

'ero=ides the blea&hing bath is &om'osed o! hydrogen 'ero=ides (/1% or 1$% by t:) as the

blea&hing agent8 an a&ti,ator (usually al2ali) and stabili.er:

/yeing machine

In te=tile >nishing 'ro&esses8 a!ter 'retreatment the dyeing 'ro&esses is ta2es 'la&e it is the

'ro&esses o! shading the !abri& by using dyes:

(round;7ighter Shade

This 'ro&ess is done by a''lying &olor8 binder and soa' hi&h shades the !abri& lighter:

9igger /yeing Machine

igger or dyeing ma&hine is one o! the oldest dyeing ma&hines used !or &loth dyeing o'erations:

igger ma&hine is suitable !or dyeing o! o,en !abri&s8 u' to boiling tem'erature ithout any


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&reasing: It has to main rollers hi&h re,ol,e on smooth bearings and are atta&hed to ith a

suitable dri,ing me&hanism8 hi&h &an be re,ersed hen re7uired: The !abri& is ound on one o!

the main rollers and!ed !rom the other:

nishing &hemi&als and also shade ,ariation is ad5usted:


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.unction of Stenter machine

Stret&h the !abri& and re&o,er the idth

Bidth o! the !abri& is &ontrolled by the Stenter

Finishing &hemi&al a''ly on !abri& by the Stenter

+rinting Machine

In "DTSC 'rinting ma&hine uses a &ylindri&al s&reen that rotates in a >=ed 'osition rather than a

?at s&reen that is raised and loered o,er the same 'rinting lo&ation so its naedJimmer rotary

'rinting ma&hine:In rotary 'rinting8 the !abri& tra,els at a &onsistent s'eed beteen the s&reen and

a rubber im'ression roller immediately belo the s&reen: The im'ression roller ser,es the same

!un&tion as the 'ress bed on a ?atbed 'ress: As the !abri& 'asses through the rotary unit8 the s&reen

s'ins at a rate that identi&ally mat&hes the s'eed o! substrate mo,ement: The s7ueegee on the

rotary 'ress is in a >=ed 'osition ith its edge ma2ing &onta&t the inside sur!a&e o! the s&reen

're&isely at the 'oint here the s&reen8 substrate8 and im'ression roller &ome together: In2 is

automati&ally !ed into the &enter o! the s&reen and &olle&ts in a edge+shaped &well fored by the

loading side of the s#ueegee and the screens interior surface.

'ig( printing achine

Calendaring Machine

It is the modi>&ation o! the sur!a&e o! the !abri& by the a&tion o! heat and 'ressure: It ta2es stem as

a sour&e8 and then this stem is &onne&ted ith di


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More ?e=ibility

In&reased reliability

asier to troubleshooting

Ma'or Components . +7C

Central Pro&essing nit (CP)

In'utout'ut (I)

Poer Su''ly

Programming De,i&e


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'oer to the >eld de,i&es: Bith larger systems8 'oer to >eld de,i&es is 'ro,ided by e=ternal

alternating &urrent (AC) or dire&t &urrent (DC) su''lies

C) +rocessor

The 'ro&essor module &ontains the PLC mi&ro'ro&essor8 its su''orting &ir&uitry8 and its mainmemory system: The main !un&tion o! the mi&ro'ro&essor is to analy.e data &oming !rom >eld

sensor through the in'ut module8 ma2es de&isions based on the user de>ned &ontrol 'rogram and

return signal ba&2 through out'ut module to >eld de,i&e:

d) +rogramming de!ice

This de,i&e is used to 'ro,ide to enter the desired 'rogram that ill determine the se7uen&e o!

o'eration and &ontrol o! 'ro&ess e7ui'ment or dri,en ma&hine:

+7C operation

A Ty'i&ally PLC system o'erates on by reading all >eld de,i&es ,ia the in'ut inter!a&e8 e=e&ute the

user 'rogram stored in a''li&ation memory8 then based on hate,er &ontrol s&heme has been

'rogrammed by the user8 turn the >eld out'ut de,i&es on or o


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Step ,6 Chec5ing and Correction of output status

Finally8 a PLC &he&2s u' out'ut signals and ad5ust it has needed: Changes are 'er!ormedbased on

the in'ut status that had been read during the >rst ste' and based on the result o! the 'rogram

e=e&ution in ste' to !olloing e=e&ution o! ste' three PLC returns a beginning o!the &y&le and

&ontinually re'eats these ste's:

2$,$- +rotection and Control /e!ices

2$,$-$% "lectrical Circuit Brea5er

A &ir&uit brea2er is a 'rote&ti,e de,i&e that interru'ts &urrent ?o in a !ault &ondition: It is

not intended !or routine use to turn the load on and oed abnormal &ir&uit &onditions8

su&h as those o! a short &ir&uit:

Components of Circuit &rea5er

The >,e basi& &om'onents o! a &ir&uit brea2er are*

Frame8 or &ase made o! metal8 or some ty'e o! ele&tri&al insulation

le&tri&al &onta&ts

'erating me&hanism

Tri' unit8 &ontaining either a thermal element8 or a magneti& element or both

peration of circuit &rea5er

In order to allo 'oer to 'ass through the brea2er8 the o'erating le,er is 'la&ed in the N

'osition: This me&hani&ally &loses the &onta&t in the brea2er: Bhen &urrent 'ass through the

de,i&e; a magneti& >eld is de,elo'ed in the bar: The intensity o! this >elds !o&uses through a large

'ie&e o! metal at the end o! mo,able arm: Bhen the &urrent e=isted as 'redeterminedamount8 the

magneti& >eld ill 'ull to the right8 releasing the le,er and the tri' me&hanism8alloing the s'ring

to 'ull &onta&t o'en:

.unction of Circuit &rea5er

1< Circuit *rea4ers as s:itc-

Sit&hes ('ass8 but do not &onsume ele&tri&al energy) are &onsidered as being &ontrol de,i&es8 thus one mayalso say that a brea2er is a &ontrol de,i&e8 or a &ontroller: A &ir&uit brea2er &an &ontrol and 'rote&t anele&tri&al &ir&uit and 'eo'le o'erating the utili.ation e7ui'ment:


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2) As current le!els to &e &ro5en

In &urrent 7uantity brea2er must be able to o'en ,erload le,el &urrents : ,erloads8 !or our

'ur'oses8 &an be understood the re7uirements !or o,erload 'rote&tion !or motors:

,) As o!er current protection

Any &urrent in e=&ess o! the rated &urrent o! the e7ui'ment or the &a'a&ity o! a &ondu&tor: ,er

&urrent &onditions are &aused by de!e&ti,e &ondu&tor insulation8 e7ui'ment8 or an e=&essi,e

or2load burden 'la&ed u'on the utili.ation e7ui'ment and its ele&tri&al &ir&uit:Cir&uit brea2ers

'ro,ide a le,el o! sa!ety against o,er &urrent &onditions in ele&tri&al &ir&uits!

2$,$-$2 Contactor

Conta&tor is ha,ing only one 'osition o! rest8 o'erated ele&trome&hani&ally and &a'able o! ma2ing8&arrying and brea2ing &urrents under normal &ir&uit &onditions8 in&luding o,erload o'erations: A&onta&tor does not 'ro,ide o,erload 'rote&tion: Conta&tors are used toele&tri&ally turn on or o=ed &onta&ts together: Bhen the &onta&tor &oil is deenergi.ed8 gra,ityor a s'ring returns the ele&tromagnet &ore to its initial 'osition and o'ens the &onta&ts:

2$,$-$, !erload Relay3elays &ontrol &urrent ?o in a &ir&uit based on signals obtained !rom an in!ormation sour&e: A relay is asim'le ele&trome&hani&al sit&h made u' o! an ele&tromagneti& &oil and a set o! &onta&ts: An ele&tri& signal(9oltage) gets sent to the &oil &reating a magneti& >eld8 &losingthe armature8 hi&h &loses Normally 'en(N::) and o'ens Normally Closed (N:C:)Conta&ts:

peration principle of !erload Relay

4 relay is an electromagnetically operated switch! "t consists o an operating coilwound around an electromagnet pole piece, a moving armature and one or moresets o contacts! 5hen a voltage o the correct value is applied across the coilterminals, the resulting current ow through the coil produces a magnetic feldsimilar to a bar magnet! The armature is attracted by the magnetic feld and so

moves a small distance!

2$,$-$- "lectrical .use

In ele&troni&s !use is a ty'e o! lo resistan&e resistor that a&ts as a sa&ri>&ial de,i&e to 'ro,ide o,er &urrent'rote&tion8 o! either the load or sour&e &ir&uit: Its essential &om'onent is a metal ire or stri' that meltshen too mu&h &urrent ?os8 hi&h interru'ts the &ir&uit in hi&h it is &onne&ted: Short &ir&uit8o,erloading8 mismat&hed loads or de,i&e !ailure are the 'rime reasons !or e=&essi,e &urrent:

2$,$-$0 In!erter

An in,erter is a motor &ontrol element that ad5usts the s'eed o! an AC indu&tion motor: It does this by

,arying the !re7uen&y o! the AC 'oer to the motor: An in,erter also ad5usts the ,oltage to the motor: Mostin,erters do their 5ob by 'er!orming to main !un&tions* >rst they &on,ert the in&oming DC into AC8 andthen they ste' u' the resulting AC to mains ,oltage le,el using a trans!ormer: The goal o! the designer is toha,e the in,erter 'er!orm these!un&tions as e&iently as 'ossible8 so that as mu&h as 'ossible o! the energydran !rom thebattery or solar 'anel is &on,erted into mains ,oltage AC8 and as little as 'ossible is astedasheat:


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2$,$-$1 Rectifier

A 3e&ti>er is an ele&tri&al de,i&e that &on,erts alternating &urrent (AC)8 hi&h 'eriodi&ally re,ersesdire&tion8 to dire&t &urrent (DC)8 hi&h ?os in only one dire&tion: The 'ro&ess is 2non as re&ti>&ation:Physi&ally8 re&ti>ers ta2e a number o! !orms8 in&luding semi&ondu&tor diodes8 sili&on+&ontrolled re&ti>ersand other sili&on+based semi&ondu&tor sit&hes: 3e&ti>ersha,e many uses8 but are o!ten !ound ser,ing as&om'onents o! DC 'oer su''lies and high,oltagedire&t &urrent 'oer transmission systems: "e&ause o!the alternating nature o! thein'ut AC sine a,e8 the 'ro&ess o! re&ti>&ation alone 'rodu&es a DC &urrentthat8 thoughunidire&tional8 &onsists o! 'ulses o! &urrent: 3e&ti>ers are used in ,arious de,i&es8 in&lude*

DC 'oer su''lies

A sour&e o! 'oer instead o! generating &urrent

High+,oltage dire&t &urrent 'oer transmission systems

2$,$-$ "lectrical switch

le&tri&al sit&h &ontrols a me&hani&al or ele&tri&al or ele&troni& de,i&e !or ma2ing or brea2ing or &hangingthe &onne&tions in a &ir&uit: In ele&tri&al sit&h is an ele&tri&al &om'onent that &an brea2 an ele&tri&al&ir&uit8 interru'ting the &urrent or di,erting it !rom one&ondu&tor to another:The most !amiliar !orm o!sit&h is a manually o'erated ele&trome&hani&al de,i&e ith one ormore sets o! ele&tri&al &onta&ts8 hi&hare &onne&ted to e=ternal &ir&uits: a&h set o! &onta&ts&an be in one o! to states* either &losed meaningthe &onta&ts are tou&hing and ele&tri&ity &an ?o beteen them8 or o'en8 meaning the &onta&ts arese'arated and the sit&h is no&ondu&ting:

2$,$-$< Transformer

The trans!ormer used on the &ontrol system is normally ste'+don trans!ormers: They are used to ste' the,oltage don !rom the line ,oltage to the &ontrol &ir&uit ,oltage: sed in thisay8 the trans!ormer is &alled a&ontrol 'oer trans!ormer or CPT:

2$,$-$4 Sensor

A sensor is a de,i&e that measures a 'arti&ular &hara&teristi& o! an ob5e&t or system: It is also a de,i&e thatdete&ts and res'onds to some ty'e o! in'ut !rom the 'hysi&al en,ironment: Thes'e&i>& in'ut &ould be light8heat8 motion8 moisture8 'ressure8 or any one o! a great number o! other en,ironmental 'henomena:Theout'ut is generally a signal that is &on,erted to human+readable dis'lay at the sensor

lo&ation or transmitted ele&troni&ally o,er a netor2 !or reading or !urther 'ro&essing: Some sensors are'urely me&hani&al8 but most sensors are ele&troni&8 returning a ,oltage signal that &an be &on,erted into ause!ul engineering unit: Sensors ta2e ad,antage o! the me&hani&al orele&tri&al res'onse o! its &om'onentsto relate the res'onse to a rele,ant 7uantity:

Some Types of "lectrical sensor

%) "lectrical Sensor3lectrical sensors e(amine the change in electrical or magnetic signals based on anenvironmental input! 3(amples o electrical sensors are metal detectors, C4+4Csystems and even simple electrical meters such as voltmeters and ohmmeters!Magnetometers are widely used in traKc intersections to detect the presence o avehicle!


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2) ptical Sensor

@ptical sensors use principles o light to 9uantiy object characteristics! The mostcommon optical sensor is the electric eye, which uses a beam o light to detect thepresence o an object! )hoto detectors and motion detectors act as switches to turnlighting systems on and o#! "t has advantages with regard to visual appearance othe yarn! @ne dimensional sensor comes to very close to observation o human eyeG

whereas, two dimensional @ptical sensor o#ers advantages or the determination othe roundness and the density o the Larn:

,) Chemical Sensor

Chemi&al sensor measures the 'resen&e and 7uantity o! a s'e&i>& &hemi&al in an en,ironment: Some&hemi&al sensors in&lude radon and &arbon mono=ide dete&tors8automobile o=ygen sensors and 'H sensors:Some &hemi&al sensors are designed to dete&t as'e&i>& &om'ound or ion !or s'e&iali.ed testing o'erations:It is a''li&able in blea&hingma&hine8 'rinting ma&hine !or adding o! dyeing &hemi&als!

-) Temperature Sensor

Tem'erature sensor sim'ly re'orts the tem'erature o! a 'art or en,ironment: The most&ommon ty'e o!tem'erature sensor is the thermo&ou'le8 hi&h relies on ,oltage &hanges based on dissimilar metal5un&tions: Thermo&ou'les are a,ailable !or a ide range o! tem'eratures8 !rom ambient en,ironmentaltem'eratures through high tem'eratureen,ironments8 su&h as 5et engines:

0) Mechanical Sensor

Me&hani&al sensor measure the &hange in a me&hani&al 'ro'erty o! an ob5e&t or system: The 'rimaryme&hani&al sensor is the strain gauge8 hi&h !orms the basis o! se,eral di


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de'endent on the !re7uen&y o! the ele&tri&al sour&e and the number o! indings8 or 'oles8 in the stator:Three+'hase AC indu&tion motor are idely used in many >elds: They are &lassi>ed in to

&ategories*

S7uirrel &age motor

Bound+rotor motor

Ad!antages of Induction Motor

The most &ommon ad,antages o! AC indu&tion motor are*

3ugged &onstru&tion

3eliable o'eration

Lo initial &ost

asy o'eration and sim'le to maintenan&e

Sim'le &ontrol gear !or starting and s'eed &ontrol

High e&ien&y

/isad!antage of Induction Motor

3elati,ely 'oor starting tor7ue

Bants to turn at &onstant s'eed (1$H. di,ided by hal! the number o! 'oles)

Cannot turn !aster than #1$$r'm (0+'ole motor)

Dras a massi,e starting &urrent8 or is ine&ient8 or both

Kind o! big and bul2y !or the 'oer it de,elo'

Specifications of MotorThe main s'e&i>&ations o! a three 'hase indu&tion motor !or designing 'ur'oses are*

#: 3ated out'ut in H:P or K:B 4: S'eed

-: Fre7uen&y 6: Ty'e/: 9oltage : Poer !a&tor0: Conne&tion : Tor7ue

1: Current

2$,$1$2 Construction of Three phase Induction Motor

Three phase induction motor is robust and, because o its simplicity and trouble reeeatures, it is the type o motor most commonly employed or industrial use! "t has

si( essential main parts, namely*

#) n&losure 0) "earings-) Stator 1) Conduit "o=/) 3otor 4) ye "olt

%) "nclosure

i: Holds 'arts together:

ii: Hel's ith heat dissi'ation:


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iii: In some &ases8 'rote&ts internal &om'onents !rom the en,ironment:

2) Stator 83indings)

i: Stationary 'art o! the motor sometimes re!erred to as the indings:

ii: Slotted &ores made o! thin se&tions o! so!t iron are ound ith insulated &o''er ire to !orm one ormore 'airs o! magneti& 'oles:

,) Rotor

i. ,-otating part of the otor.

ii. /agnetic field fro the stator induces an opposing agnetic field onto the rotor causing the

rotor to ,push away fro the stator field:

-) Bearings

a) Slee!e Bearings &) Ball 8Roller)Bearings

i: Standard on most motors i: Su''ort sha!t in any 'ositionii: Ouiet ii: Grease lubri&ated

iii: Hori.ontal sha!ts only iii: Many &ome sealed re7uiring no maintenan&ei,: il lubri&ated

0) Conduit Bo#* )oint of connection of electrical power to the otors stator windings.

1) "ye Bolt6 sed to li!t hea,y motors ith a hoist or &rane to 're,ent motor damage:

"./.= I)5ucti() #(t(r C()tr(22er

4 motor controller is the actual device that energizes and deenergizes the circuit tothe motor so that it can start and stop! Motor controllers may include some or all othe ollowing motor control unctions:

starting, stopping, overcurrent protection, overload protection, reversing,speed changing, jogging, plugging, se9uence control, and pilot lightindication!

ontrollers range rom simple to comple( and can provide control or onemotor, group o motors, or au(iliary e9uipment such as brakes, clutches,solenoids, heaters, or other signals!

There are di#erent types o three phase motor controlling methods! These are:1. #a)ua2 m(t(r C()tr(2: ontrol is considered to be manually operated when

someone must initiate an action in order or the circuit to operate! $omeone mighthave to ip the switch o a manual $tarter to start and stop a motor!". Aut(matic m(t(r Oerati()>#a0)etic m(t(r c()tr(22er9 5hile manualoperation o machines is still common practice, many machines are started andstopped automatically!/. C(m*i)e5 (erati(): There is a combination o manual and automatic control!4 process may have to be started manually, but may be stopped automatically!


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C(m()e)ts (, c()tr(2 circuit

*eore going to the design o control circuits it is necessary to have an idea o thedi#erence type o control circuit's components! The ollowing are some o theimportant components used in contactor control circuits! $ome o the important

components are: "! )ush *utton ""! ontactors"""! @verload Celays

"./.1? I)5ucti() #(t(r Starter

4 7phase induction motor is theoretically selstarting! The stator o an inductionmotor consists o 7phase windings, which when connected to a 7phase supplycreates a rotating Magnetic feld! This will link and cut the rotor conductors which inturn will induce a current in the rotor conductors and create a rotor magnetic feld!

The magnetic feld created by the Cotor will interact with the rotating magnetic feld

in the stator and produce rotation!Thereore, 7phase induction motors employ a starting method not to provide astarting tor9ue at the rotor, but because o the ollowing reasonsG -> Ceduce heavy starting currents and prevent motor rom @verheating! 8> )rovide overload and novoltage protection!

There are many methods in use to start 7phase induction motors! $ome o thecommon methods are:

+irect @n&ine $tarter =+@&>

$tar+elta $tarter

4uto Transormer $tarter

Cotor "mpedance $tarter

"./.11 B(i2er System

"n *+T$ some electrical machines like printing machine, drying machine,calendaring, and sizing machine needs boiled water or manuacturing process! 4boiler is basically a closed vessel into which water is heated until the water isconverted into steam at re9uired pressure

8(r4i)0 Pri)ci2e (, B(i2er

The basic working principle o boiler is very simple and easy to understand! Theboiler is essentially a closed vessel inside which water is stored! is burnt in a urnace and hot gasses are produced! These hot gasses come in

contact with water vessel where the heat o these hot gases transer to the waterand conse9uently steam is produced in the boiler! Then this steam is piped to theturbine o thermal power plant! The boiled water pumped out through long tubes toevery section o the company! There are many di#erent types o boiler utilized ordi#erent purposes like running a production unit, sanitizing some area, sterilizinge9uipment, to warm up the surroundings o the working sections o the company!


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"./.1" Air C(mress(r System

4ir compression is achieved by the interaction o a f(ed and orbiting scroll! 4ir atinlet pressure enters the compression chamber at the e(terior side o the scrollelement! @nce air is drawn in, the orbiting scroll seals o# the inlet port! 4s the scrollcontinues to orbit, the air is progressively compressed into an increasingly smallerpocket'! 4 continuous ow o compressed air leaves the scroll element through adischarge port in the center o the f(ed scroll! This process is continuouslyrepeated, resulting in the delivery o pulseree compressed air! The producedcompressed air is stored in the air storage tanker, and then pumped out to thecompany sections by using high pressure valve tubes! This high pressure aircompressed to the specifc electrical machinery to perorm a task!

"./.1/ Air C()5iti()i)0 System

Coving, ring, picanol and somet machine o the actory uses blowing apparatus toproduce a signifcant 9uantity to y they also continually stir it up! This necessitatesa corresponding e#ort to keep installation clean! To relieve attendants at least partlyo this burden, traveling blowers are now increasingly being used! These consistessentially o a powerul an that moves back and orth on rails above the machine!

"./.13 8aste a)5 Dust Rem(va2 System

The company use highpressure vacuum systems to collect waste rom every areain a te(tile mill! These systems use automatic valves at airhandling separators suchas flter bags, fber separators, condensers, fnedust flters and cyclones The valvesare controlled by a programmable controller and collect waste directly at the site osome production e9uipment, including cleaning lines, cards, traveling cleanercollection bo(es and spinning rame suction bo(es!"n the fberrecovery room, various waste categories are conveyed to the wasteroom by high vacuum and collected in the appropriate fber receivers, which areautomatically emptied into waste receptacles! The fne dust passing through theseparator screen o the waste receiver is collected in the fnedust pulsejet flter,rom which the dust can be manually or automatically emptied! The vacuum pumpis an economically operated centriugal e(hauster, sized or specifc millre9uirements! The vacuum pump is a centriugal e(hauster that uses amperageaccording to air volume! Twin automaticdischarge fber receivers =primaryseparators> operate together to produce a constant vacuum or separately as singlereceiver systems! 5aste is separated by a sel cleaning stainlesssteel separatorscreen and is automatically discharged to a waste receptacle! 4 patented, rotatingcompressedair mechanism cleans the separator screen, which is easily removed byway o a special litup top section i servicing is re9uired! The pulsejet flter is afnedust flter that operates as a secondary separator to collect the dust enterstangentially and drops rom the air stream to a plenum or manual or automaticcollection! ompressed air Nenturis clean the fltration media! These units are selcleaning and selemptying! The centralized dustcollection system automaticallycollects dust rom airhandling and vacuum dust flters throughout a mill! This dustis conveyed to a special pulsejet flter or automatic disposal through a valvesystem to a compacting auger, plastic bag!


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".3 #a+(r Duties (, t-e I)ter)

The major responsibilities that we had done as an intern in *+T$ are: 5riting a report on each section o the company every two weeks

4ssisting company operators

Cespect rules and regulations o the company

Making problem solving projects in each section 5orking as a motor repair man

".6 C-a22e)0es Face5 a)5 #easures

".6.1 C-a22e)0es

5e were perorming di#erent tasks in our intern period and the ollowing problemsare aced:

Most o company worker are uneducated and are not voluntary to answerany 9uestions that are related to the task they worked on!

5e were unable to get inormation about machines manual and some useuldocuments about the company!

Digh sound pollution in the weaving section o the company challenging usto get inormation related to this section and it may cause hearing loss!

There is a high amount o dust in spinning section that causes unable to see!

".6." T-e #easures Ta4e) t( S(2ve t-e C-a22e)0es

5e take di#erent measurement in order to solve the challenge:


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C-ater /

Be)e@ts !ai)e5 ,r(m t-e I)ter)s-i

/.1 U0ra5i)0 t-e T-e(retica2 )(:2e50e

The contribution o the internship program is not only or practical but it also

upgrades our theoretical knowledge! "t increases the ability to apply systematic

design procedure to open ended problem and how to analyses something

technicallyG so it upgrades our theoretical knowledge the same as the practical one!

"nternship memorizes the important conceptual theoretical parts that we have

learned among the important ones that the internship upgrades our theoretical

parts include:

Inderstanding the wiring diagram o the machine

The power distribution o the company

The operation o di#erent electric devices like transormer, cont actor, and

generator

5e have seen the real practical world and understood the work ow and interaction

between di#erent levels o the organization! 5e saw the procedures and ways o

e(periment tests or the 9uality control and assurance and we are also work as an

operator in each section measures like machine setting, machine element changing,

maintenance in the power control plant, etc! are taken to correct aults according to

the 9uality control oKce report! The e#ects are o raw material 9uality, mechanical% electrical conditions o machines, lack o skillul operators air conditioning and

cleaning on production and waste is a great impact!

/." Imr(vi)0 I)terers()a2 C(mmu)icati() s4i22

Ceally, we have seen that without e#ective communication skills, an employee

cannot succeed in the workplace! " communication can ail or i a message can be


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understood in di#erent ways, it will be understood in the way which does the most

harm! Aenerally we have gained the ollowing interpersonal communication skillsG

&istening skill


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4lso learns some solve any problems developed

/.6 Deve2(i)0 8(r4 Et-ics

The beneft o the internship program was interesting in improving ethical work

habit! 4lthough it is diKcult to memorize all benefts that are gained about work

ethics, it is important to mention the ollowing:

&earning and respecting o any work tasks that were important in order to do

those tasks e#ectively % eKciently

*e on time at work and leave work by the right time =punctuality>

*e responsible in analyzing and interpreting gathering o data

*eing loyal and honest when doing judgments on work

Aood work ethics oten inspire others to act in similar ways! Many people consider

eKcient production a hallmark o good work ethics! )roductivity doesnOt have tomean a huge outputG it could mean consistent 9uality yield as well!

/.7 E)trere)eurs-i

3ntrepreneurship is the ability o a person to create business or an enterprise o

hisEher own! This internship program develops our creativity and we detect that the

private sector is better than the public sector to get better business! To be good

entrepreneur, the ollowing abilities or skills are needed!

a! Cisk management

b! $el confdence

c! "nnovative skills

d! Market understanding ability

e! 3ducational background


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CHAPTER FOUR

PROJECT

PRO&ECT TITLE 9 I#PRO%E#ENT OF FOR8ARD RE%ERSE #OTOR

USIN! TI#E DELA' RELA'

ABSTRACT

"nduction motor is the most important part that makes this project success!

This motor is chosen because it simple, rugged construction, easy

maintenance! "t's commonly used especially or higherpowered motors!


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Peywords: "nduction motor, Timer=Time delay relay>,3lectromechanical

relay=ontactor>, 3lectrical motor control

4.1 ITRO!"CTIO

3.1." BAC !ROUND

)ower distribution systes used in large coercial and industrial applications can be cople$.

)ower ay be distributed through switchgear% switchboards% transforers% and panel boards.

)ower distributed throughout a coercial or industrial application is used for a !ariety of

applications such as heating% cooling% lighting% and otor0dri!en achinery. nlike other types

of power distribution e#uipent% which are used with a !ariety of load types% otor control

centers priarily control the distribution of power to electric otors.

2here!er otors are used% they ust be controlled. In Basics of Control Coponents!arious

control products are used to control the operation of otors. 'or e$aple% the ost basic type of

3C otor control% in!ol!es turning the otor on and off. This is often accoplished using a

otor starter ade up of a cont actor and an o!erload relay. The cont actor4s contacts are closed

to start the otor and opened to stop the otor. This is done electro echanically and often

re#uires using start and stop pushbuttons and other de!ices wired to control the cont actor.

The forward re!erse otor control is used where forward and backward or upward anddownward o!eent in the operation is needed. The clockwise +forward5 and counterclockwise

+re!erse5 rotation of a otor can be caused by interchanging the connection of any of the two of

its three terinals

To change the direction a three phase induction achine rotation% two of its phae$changed% thus

changing the phase se#uence for% say 3BC to CB3. This can be accoplished by using two

contact ors% one for the forward or C2 rotation and one for the re!erse or CC2 rotation. The

forward and re!erse cont actors are echanically interlocked i.e.% if one of the is closed the

other cannot close. This is done to a!oid dead short circuit in case both the cont actors closing

siultaneously. 3lso electrical interlocking could be pro!ided using the cont actors controlcontacts. the instruents are three phase induction otor %tie delay relay% o!er load relay

%fuse%electroechanical relay

the otor circuit also uses the o!erload input% which will shut down the otor. The norally

closed o!erload contacts are prograed as norally open in the logic dri!ing the otor starter


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outputs. The forward and re!erse otor coands will operate norally if no o!erload

condition e$ists because the o!erload contacts will pro!ide continuity

3.1." PROBLE# STATE#ENT

"n order to become economical you must have everything must be used in

manageable or controllable way !these motor control would minimize actors

like decreasing the working age o splitting table,ma(imize the suitability o

labor worker by decreasing the noise in case when the roller hit the splitting

wall and when the roller is not stopped by the wall it damages the labor

worker and spent money or medical as well as it becomes dependent on

others!

3.1./ O*+ective

to show the power circuit

to show control circuit

how to integrate the power circuit and control circuit

To change the direction of a three phase induction otor rotation.

3.1.3 SI!NIFICANCE

3fter de!eloping this pro"ect

a!oid In"ured labor worker

increase the working age of the table which is used for split the

fabric

stop the roller without huan interface

3.1.6 LI#ITATION OF THE PRO&ECT

This project operates by push button orward, reverse and stop buttons !i t

works using time delay relay in order to stop the orward reverse movement

o the motor which rotates the roller !when we press the orward pushbutton

it will run up to predetermined amount o time and when we press reverse

push button it will run in reverse direction! "t does not return by itsel it

needs an operator!


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3." RE%IE8 LITRATUREcranes for speed and direction% also for raising and lowering of the crane hoist. 6lectric -ailway

systes utilize this technology for forward and re!erse speed control. This specific e$aple is

suitable to use for a /odel -ailway application% howe!er there are other circuit ethods which

use a single )ort )in for )icpatch 7otor control8 This technology is used on a uch larger scale

for tra!erse control of 'orward 9 -e!erse Speed control. 3 coon switch echanis used in

these applications is the :oy0Stick control ethod. The hand o!eent control action of the

:oystick should correspond with the direction of o!eent and speed of the crane gantry% hoist

or locooti!e engine. /o!ing the :oystick handle to the right would o!e the crane to the right%

or o!ing the :oystick forward will o!e the train forward etc

/uhaad akurzab B/ zuai7three phase otor controller8 The de!elopent of induction

otor controller pro"ect is a part of three phase induction otor control syste that will be

designed based on icro0controller using /C;?


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3./#ATERIALS AND #ETHDOLO!'

3./.1 #ATERIALS

3./.1.1 INDUCTION #OTOR


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@ne o the most common electrical motorused in most applications which is

known as induction motor! This motor is also called as asynchronous otor

because it runs at a speed less than synchronous speed! "n this, we need to

defne what synchronous speed is! $ynchronous speed is the speed o

rotation o the agnetic field in a rotary machine and it depends upon the

re9uency and number poles o the machine! 4n induction motor always runs

at a speed less than synchronous speed because the rotating agnetic field

which is produced in the stator will generate u( in the rotor which will make

the rotor to rotate, but due to the lagging o u( currentin the rotor with u(

current in the stator, the rotor will never reach to its rotating agnetic field

speed i!e! the synchronous speed! There are basically two types o induction

motor that depend upon the input supply 0 single phase induction otorand three

phase induction otor. Single phase induction otoris not a sel starting motor! and

three phase induction otoris a selstarting motor! Jow in general we need to

give two supply i!e! double e(citation to make a machine to rotate!


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a covering and provide protection and mechanical strength to all the inner

parts o the machine! The rame is either made up o die cast or abricated

steel! The rame o three phase induction motorshould be very strong and

rigid as the air gap length o three phase induction motor is very small,

otherwise rotor will not remain concentric with stator which will give rise to

unbalanced magnetic pull!

" Stat(r c(re: The main unction o the stator core is to carry alternating u(! "n

order to reduce the eddy currentlosses the stator core is laminated! This laminated

type o structure is made up o stamping which is about .!2 to .!1 mm thick! 4ll the

stamping are stamped together to orm stator core, which is then housed in stator

rame! The stamping are generally made up o silicon steel, which reduces the

hysteresis loss!/ Stat(r :i)5i)0 (r @e25 :i)5i)0:The slots on the periphery o stator

core o the three phase induction motorcarries three phase windings! This

three phase winding is supplied by three phase ac supply! The three phases

o the winding are connected either in star or delta depending upon which

type o starting method is used! The s9uirrel cage motor is mostly started by

star R delta stator and hence the stator o s9uirrel cage motor is delta

connected! The slip ring three phase induction motorare started by inserting

resistances so, the stator winding can be connected either in star or delta!

The winding wound on the stator o three phase induction motor is also

called feld winding and when this winding is e(cited by three phase ac

supply it produces rotating magnetic feld!

R(t(r:The rotor is a rotating part o induction motor! The rotor is connected

to the mechanical load through the shat!

3./.1.1." T'PES OF THREE PHASE INDUCTION #OTOR

+epending upon the type o rotor used the three phase induction motorare

classifed as

- $9uirrel cage induction motor
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8 $lip ring induction motoror wound induction motoror phase wound

induction motor

3./.1.1./ 8ORIN! PRINCIPLE OF INDUCTION #OTOR

5hen we are giving the supply to the stator winding, u( will generate in the

coil due to ow o currentin the coil! Jow the rotor winding is arranged in

such a way that it becomes short circuited in the rotor itsel! The u( rom

the stator will cut the coil in the rotor and since the rotor coils are shortcircuited, according to , )ulse Aenerator, @ne $hot, @nE@# +elay, and Memory &atch! !

Time delay relays have a broad choice o timing ranges rom less than one
http://www.electrical4u.com/electric-current-and-theory-of-electricity/http://www.electrical4u.com/faraday-law-of-electromagnetic-induction/http://www.electrical4u.com/electric-current-and-theory-of-electricity/http://www.electrical4u.com/electric-current-and-theory-of-electricity/http://www.electrical4u.com/electric-current-and-theory-of-electricity/http://www.electrical4u.com/faraday-law-of-electromagnetic-induction/http://www.electrical4u.com/electric-current-and-theory-of-electricity/http://www.electrical4u.com/electric-current-and-theory-of-electricity/


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second to many days! There are many choices o timing adjustments rom

calibrated e(ternal knobs, +") switches, thumb wheel switches, or recessed

potentiometer! The output contacts on the electromechanical output relay

are direct wired to the output terminals! The contact load ratings are

specifed or each specifc type o time delay relay! Time delay relays are

simply control relays with a time delay built in! Their purpose is to control an

event based on time! The di#erence between relays and time delay relays is

when the output contacts open %close: on a control relay, it happens when

voltage is applied and removed rom the coilG on time delay relays, the

contacts will open or close beore or ater a perselected, timed interval!

Time delay is arranged to stop at -; seconds ater the motor have been

started!

'ig @.A( tie delay relay

3./.1./ E2ectr(mec-a)ica2 re2ay C()t act(r, such as lights, heaters and motors! The unction o the

contactor is always the sameG to make and break all power supply lines


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running to a &oad or, as defned by J3M4, to repeatedly establish and

interrupt an electrical power circuit!

3./.1.3 Over 2(a5 Re2ay

4 relay that opens a circuit when the load in the circuit e(ceeds a presetvalue, in order to provide overload protectionG usually responds to e(cessive

current, but may respond to e(cessive values o power, temperature, or

other 9uantities! 4lso known as overload release! 4 relayin the circuit o a

motor which causes the motor to be disconnected rom its source o power i

the current to the motor e(ceeds a predetermined value!

3./.1.6 Fuse


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3./."./ FOR8ARD RE%ERSE #OTOR CONTROL

'[email protected]( o!er all forward re!erse otor control

final intership report.docx

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