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PHYSICSPHYSICSPROJECTPROJECT
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Certifcate
Acknowledgement
AIM
Principle
Introduction o transormer
Construction
Theory and working
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Energy losses
Material required
Circuit diagram
Procedure
Oser!ation conclusion
Precaution
"ources o error
#ses o transormer
iliography
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This is to certiy that the pro$ect work titled %To
investigate the relation between input and output
voltage of a TRANSFORMER %eing sumitted as aPro$ect &eport or the ulfllment o curriculum o
CE'T&A( )OA&* O+ "ECO'*A&, E*#CATIO'
-C)"E./ is a record o a onafde work carried out
y Sanskriti rom 0ueen Mary1s "chool/ 'orthend
under my guidance and super!ision during the
session April 2345 6 March 23478
E9AMI'E&Mrs8 'eha :hannaP;T -Physics. Teacher0ueen Mary1s "choolModel Town/ *elhi
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To investigate the
relation between theratio of
i) Input and Output
voltage
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ii) u!ber of turns in
the se"ondar# "oil andpri!ar# "oil of a self
designed transfor!er$
% transfor!er "onsistsof two ele"tri"all#
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isolated "oils and
operates on &arada#'sprin"ipal of (!utualindu"tion* in whi"han E+& is indu"ed in
the transfor!ersse"ondar# "oil b# the!agneti" ,u-generated b# the
voltages and "urrents,owing in the pri!ar#"oil winding$
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I'T&O*#CTIO'
O+
T&A'"+O&ME&A transformer is an electrical device that is
used to convert alternating current at low
voltage or visa versa, through electromagnetic
induction. If it increases the input voltage
then it is called step-up transformer and if it
decreases the input voltage then it is called
step-down transformer. It is based on mutual
inductancebetween two or more winding that is
responsible for transformation action in anelectrical transformer.
https://en.wikipedia.org/wiki/Electromagnetic_inductionhttps://en.wikipedia.org/wiki/Electromagnetic_inductionhttps://en.wikipedia.org/wiki/Electromagnetic_inductionhttps://en.wikipedia.org/wiki/Electromagnetic_induction -
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A varying current in the transformer's primary
winding creates a varying magnetic fluxin the
transformer core and a varying magnetic fieldimpinging on the transformer's secondary
winding. This varying magnetic fieldat the
secondary winding induces a
varying electromotive force(!"# or voltage in
the secondary winding. !a$ing use
of "araday's %awin con&unction withhigh magnetic permeabilitycore properties,
transformers can thus be designed to
efficiently change Avoltages from one
voltage level to another within power networ$s.
ince the invention of the first
constant potentialtransformer in )**+,
transformers have become essential for the
Atransmission, distribution, and utiliation of
electrical energy./
A wide range oftransformer designs is encountered in
electronic and electric power applications.
Transformers range in sie
https://en.wikipedia.org/wiki/Magnetic_fluxhttps://en.wikipedia.org/wiki/Magnetic_fieldhttps://en.wikipedia.org/wiki/Electromotive_forcehttps://en.wikipedia.org/wiki/Faraday's_law_of_inductionhttps://en.wikipedia.org/wiki/Permeability_(electromagnetism)https://en.wikipedia.org/wiki/Alternating_currenthttps://en.wikipedia.org/wiki/Potential_energyhttps://en.wikipedia.org/wiki/Electric_power_transmissionhttps://en.wikipedia.org/wiki/Electric_power_distributionhttps://en.wikipedia.org/wiki/Transformer#cite_note-Bedell_.281942.29-3https://en.wikipedia.org/wiki/Magnetic_fluxhttps://en.wikipedia.org/wiki/Magnetic_fieldhttps://en.wikipedia.org/wiki/Electromotive_forcehttps://en.wikipedia.org/wiki/Faraday's_law_of_inductionhttps://en.wikipedia.org/wiki/Permeability_(electromagnetism)https://en.wikipedia.org/wiki/Alternating_currenthttps://en.wikipedia.org/wiki/Potential_energyhttps://en.wikipedia.org/wiki/Electric_power_transmissionhttps://en.wikipedia.org/wiki/Electric_power_distributionhttps://en.wikipedia.org/wiki/Transformer#cite_note-Bedell_.281942.29-3 -
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from 0"transformers less than a cubic
centimeter in volume to units interconnecting
the power gridweighing hundreds of tons.
A transormer consists o a rectangular shatiron core made o laminated sheets/ wellinsulated rom one another8 Two coils p4< p2and s4< s2are wound on the same core/ ut
are well insulated with each other8 'ote thatoth the coils are insulated rom the core/ thesource o alternating E8M8+88 is connected to p4< p2/ the primary coil and a load resistance &is connected to s4s2/ the secondary coilthrough an open switch "8 Thus there can eno current through the secondary coil so longas the switch is open8
+or an ideal transormer/ we assume that theresistance o the primary < secondarywinding is negligile8 +urther/ the same =u>
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links oth the primary and secondary coil as!ery little =u> escape rom the core i8e8energy loss is also negligile8
T?EO&, A'*
@O&:I'; O+T&A'"+O&ME&@hen an altering E8M8+88 is supplied to the primary
coil p4p2/ an alternating current starts alling in it8The altering current in the primary coil produces a
changing magnetic =u>/ which induces altering
!oltage in the primary as well as in the secondary
coil8 In a goodtransormer/ whole o the magnetic
=u> linked with primary coil is also linked with thesecondary coil8 Then the induced E8M8+88/ induced in
each turn o the secondary coil is equal to that
induced in each turn o the primary coil8
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Thus i Epand Ese the instantaneous !alues o the
E8M8+881s induced in the primary coil and the
secondary coil8
(et 'pand 'sare the no8 o turns o the primary
and secondary coils o the transormer respecti!ely8
dB dt rate o change o magnetic =u> in each
turn o primary and secondary coil at a time t
The induced E8M8+88 in the primary coilD
Ep 'pdBdt -4. And
The induced E8M8+88 in the secondary coilD
Es 'sdBdt -2.
"ince the ao!e relations are true at e!ery instant/so y di!iding 2 y 4/ we get
EsB Ep 'sB
'p: -.
@here : Transormation &atio
As Epis the instantaneous !alue o ack E8M8+8induced in the primary coil p4/ so the instantaneous
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current in primary coil is due to the diFerence -E 6Ep. in the instantaneous !alues o the applied andack E8M8+88 +urther i &pis the resistance o p4p2
coil/ then the instantaneous current Ip in theprimary coil is gi!en y
Ip E 6 EpB &p
E 6 Ep Ip&p
@hen the resistance o the primary coil is small/ &p< Ipcan e neglected so thereore
E 6 Ep 3 or Ep E
Thus ack E8M8+8 input E8M8+8
?ence equation -. can e written as
EsB Ep EsB E
output E8M8+8 B inputE8M8+8
'sB 'p :
@here : is constant/ called turn or transormationratio8
In a step up transormer
EsG E so : G 4/ hence 'sG 'p
In a step down transormer
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EsH E so : H 4/ hence 'sH 'p
I/
Ip !alue o primary current at the same instant t
And/
Is !alue o sec8 current at this instant/ then
Thereore/
Input power at the instant t EpIp
And/
Output power at the same instantEsIs
I there are no loss o power in the transormer
-433 eJciency./Then/
Input power output power
EpIp EsIs
EsB Ep IpB Is 'sB 'p :
In a step up transormer
As k G 4/ so IpG Isor IsH Ip
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i8e8 current in secondary coil is weaker whensecondary coil1s !oltage is higher and numer oturns is greater than that o the primary coil8
?ence/ whate!er we gain in !oltage/ we lose incurrent in the same ratio8
"imilarly it can e shown/ that in a step downtransormer/ whate!er we lose in !oltage/ we gainin current in the same ratio8
Thus a step up transormer in reality steps downthe current < a step down transormer steps up thecurrent8
EJciencyDEJciency o a transormer is defned as the ratio ooutput power to the input power8 i8e8
output power B input power
EsIsB EpIp
Thus in an ideal transormer/ where there is nopower losses/ 48 )ut in actual practice/ thereare many power lossesK thereore the eJciency o
transormer is less than one8
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Energy lossesDI8 +lu> (eakageD
There is always some =u> leakageK that is/ not all
o the =u> due to primary passes through thesecondary due to poor designs o core or the airgaps in the core8 It can e reduced y winding theprimary and secondary coils one o!er the other8
II8 &esistance o the windingsD
The wire used or windings has some resistance or
so/ energy is lost due to heat produced in the wire-I2&.8 In high current/ low !oltage windings/ theseare minimiLed y using thick wires8
III8 Eddy currentsD
The alternating magnetic =u> induces eddycurrents in the iron core and causes heating8 ThiseFect is reduced y ha!ing a laminated core8
I8 ?ysteresisD
The magnetiLation o the core is repeatedlyre!ersed y the alternating magnetic feld8 Theresulting e>penditure o energy in the core
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appears as heat and is kept to a minimum yusing a magnetic material which has a lowhysteresis loss8
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MATE&IA(&E0#I&E*
An Iron rod
Copper wires o diFerent gauge
-diameter. Two A8C8 !oltmeter
Two A8C8 Ammeters
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48 Take a thick iron rod and co!er it with athick paper and wind a large numer oturns o thin Cu wire on thick paper8 This
constitutes primary coil o the transormer828 Co!er the primary coil with a sheet o
paper and wound relati!ely smallernumer o turns o thick copper wire on it8
This constitutes the secondary coil8 It is astep down transormer8
8 Connect P4P2to A8C8 mains and measurethe input !oltage and current/ using A8C8!oltmeter and ammeter respecti!ely8
N8 "imilarly/ measure the output !oltage andcurrent through "4"28
58 'ow connect the "4"2to A8C8 mains andagain measure !oltage and current
through primary and secondary coil ostepup transormer8
78 &epeat all steps or other sel madetransormer y changing numer oprimary turns in secondary coils8
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48 (east count o A8C8 !oltmeter
28 ero error o !oltmeter
8 &ange o !oltmeter
N8 (east count o A8C8 ammeter
58 ero error o ammeter
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78 &ange error o ammeter
Q8 Applied A8C8 !oltage
O)"E&ATIO' TA)(E
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4.
The output !oltage o the transormer across
the secondary coil depends upon the turn
ratio -'"B'P. w8r8t8 input !oltage8
2. The output current o the transormer
across the secondary coil depends upon
the turn ratio -'"B'P. w8r8t8 input current8
. There is loss o power etween input and
output coil o a transormer8
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PrecautionsA8 :eep sae yoursel rom the high
!oltage8
)8 @hile taking the readings ocurrent and !oltage/ the A8C8 mainsupply should remain constant8
"ources oerrorA8 alues o current can e changed
due to heating eFect o current8)8 The eddy current can change the
readings8
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#"E" O+
T&A'"+O&ME&
o A transformer is used in almost all A.C.
operations
In voltage regulator for T.V., refrigerator,
computer, air conditioner etc.
In the induction furnaces. A step down transformer is used for welding
purposes.
A step down transformer is used for obtaining
large current.
A step up transformer is used for the
production of X-Ras and !"#!
advertisement.
Transformers are used in voltage regulators
and stabili$ed power supplies.
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Transformers are used in the transmissions of
A.C. over long distances.
%mall transformers are used in Radio sets,telephones, loud spea&ers and electric bells etc.
)I)(IO;&AP?,
)ooksD
.$Co!prehensive Pra"ti"al Ph#si"s b# /a-!iPubli"ations 0P) /td$
1$CERT Ph#si"s "lass 2II3$/ab +anual Ph#si"s b# Saraswati Publi"ations
@esitesD
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.$ https455en$wi6ipedia$org5wi6i5transfor!ers
1$ www$s"ien"edire"t$"o!5s"ien"e5arti"le5p
ii3$ http455www$ele"troni"s$"o!5transfor!er7"onstru"tion$ht!l
8$ http455www$ele"tri"al8u$"o!5what7is7transfor!er7de9nition7wor6ing7prin"iple7of7transfor!er5
https://en.wikipedia.org/wiki/transformershttps://en.wikipedia.org/wiki/transformershttps://en.wikipedia.org/wiki/transformershttp://www.sciencedirect.com/science/article/piihttp://www.sciencedirect.com/science/article/piihttp://www.electronics.com/transformer-construction.htmlhttp://www.electronics.com/transformer-construction.htmlhttp://www.electrical4u.com/what-is-transformer-definition-working-principle-of-transformer/http://www.electrical4u.com/what-is-transformer-definition-working-principle-of-transformer/http://www.electrical4u.com/what-is-transformer-definition-working-principle-of-transformer/https://en.wikipedia.org/wiki/transformershttps://en.wikipedia.org/wiki/transformershttp://www.sciencedirect.com/science/article/piihttp://www.sciencedirect.com/science/article/piihttp://www.electronics.com/transformer-construction.htmlhttp://www.electronics.com/transformer-construction.htmlhttp://www.electrical4u.com/what-is-transformer-definition-working-principle-of-transformer/http://www.electrical4u.com/what-is-transformer-definition-working-principle-of-transformer/http://www.electrical4u.com/what-is-transformer-definition-working-principle-of-transformer/