Transformer 1 w 2

8/13/2019 Transformer 1 w 2

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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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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

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.

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Transformer 1 w 2