transformer 1 w 2
TRANSCRIPT
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Transformer Construction
Basic Component of single phase transformerLaminated iron core
Primary winding
NP
Secondary winding
NS LoadSupply
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Transformer
Configuration of single phase transformer
PrimaryWinding
SecondaryWinding
Multi-layerLaminatedIron Core
X1X2H1 H2
WindingTerminals
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Transformer
Construction of a small transformer a) Lamination b) Iron coreand winding
Iron core
Terminals
Secondarywinding
Insulation
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Transformer Dry-type 3 phase
transformer
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Transformer
Oil insulated type transformer withcooling system
Winding
Iron corebehind the steel
bar
Radiator
Steeltank
Insulation
Bushing Metal bar
Exteriorporcelain tube
Interior porcelain tube
Flange
Porcelain
transformer bushing
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Transformer
High VoltageTransformer withCooling System
Oil tank
Cooling
radiators
High voltagebushing
Low voltagebushing
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Transformer Core Material
B(H) Magnetising Curve
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 500 1000 1500 2000 2500
Magnetic Field Intensity, H (A-turn/m)
M a g n e t
i c F l u x
D e n s i
t y , B
( T
Cast Iron
Cast Steel
Ordinary Sheet Steel
Quality Sheet Steel
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Transformer Magnetic Circuit
Transformer Polarity
0 5 10 15 20100
0
100
Vp t( )
Vs t( )
t
milli s
0 5 10 15 20100
0
100
Vp t( )
Vs t( )
t
milli s
H1
H2
X2
X1
V p Vs
H1
H2 X2
X1
V p Vs
(a) (b)
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Transformer Magnetic Circuit
Amperes Law
Flux Density
Flux
N m
I m
E
A
H N I mm =
H B =
A B=Magnetic Circuit
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Voltage Induced in a Transformer
Voltage Induced
Modifying the above equation:
Voltage Induced
dt d
N E m
=
( ) ( )dt
I d N A N I
dt d
N Adt
H d N A
dt A Bd
N E mmmmmmm
2
=
===
dt
I d L E m=
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Transformer Inductance andMagnetic Energy
Inductance
Magnetic Energy
2m N A L
=
2
2m I L Energy =
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Core measurementw = 3in, h = w, a = 1in, b= 1.5in
Im = 2A, Nm = 20, f =
60Hz, Magnetic path length
and areaLm = 2 (w + a) + 2 (h + a)Acore = a b Magnetic field intensity Rajah 13: Litar Magnetik
Hm
Im Nm
Lm:= H m 98.425
A
m
=
Transformer Magnetic CircuitAnalysis
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Magnetic Circuit
Transformer Magnetic CircuitAnalysis
Magnetic flux density
free space or air permeability
Magnetic flux intensity (H)
B m o r H m:=
o 4 107
Hm:=
H m 98.425A
m=
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Transformer Magnetic Circuit Analysis
Magnetic flux
Or
Magnetising sinusoidal current
m Bm Acore:=
m o rAcore Nm
Lm Im:=
Imag t( ) 2 I m cos t( ):=
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Transformer Magnetic Circuit Analysis
Magnetic Flux a function of time
Maximum Flux :
Flux a function of time :
max 2 o rA core Nm
Lm
I:=
mag t( ) o rAcore Nm
Lm 2 Im cos t( )( ):=
mag t( ) max cos t( ):=
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Voltage Induced in a Transformer
RMS VoltageErms
Nm max
2:=
Eind t( ) Nm tmag t( )dd
:=
Eind t( ) Nm t max cos t( )( )d
d:=
Eind t( ) Nm max sin t( ):=
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Voltage Induced in a Transformer
Voltage Induced
Voltage Induced :
Erms 4.443 f Nm max:=
Eind t( ) Lind tImag t( )
d
d
Nm tmag t( )
d
d Lind t
Imag t( )d
d
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Transformer Inductance
Lind
Nm mag t( )
Imag t( )
LindNm rms
Im
LindNm max cos t( )( )
2 Im cos t( )
Lind
Nm 2 o rA core Nm
Lm
Im
2 Im:=
Lind o rAcore Nm2
Lm:=
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Typical Magnetising Curve B/H
Linear Region, material permeability is constant. Knee region , material permeability almost reaching
saturation. Saturation region.