1. INFORMATIONAL TECHNOLOGY IN EDUCATION
Name: Farah Eliza Binti Mansor
Matrix: db130320
Name:Nurul Qurraisyia Binti Zulkafli
Matrix: DB130085
Name: Fatinnazihah Binti Abdul Rahman
Matrix: DB130322
Name: Faridah Zahirah Binti Ismail
Matrix: Db130321

2. CONTENTS No Title 1 1.0 Introduction 2
2.0 Basic Construction Of A Transformer
2.1 Core
2.2 Windings 3
3.0 Operation Of Transformers
3.1 Winding Ratio
3.2 Voltage Ratio
3.3 Current Ratio 4
4.0 Loss And Efficiency Of Transformers
4.1 Ideal Transformers
4.2 Non-ideal Transformers
4.3 Transformers Efficiency 5
5.0 Application Of A Power Transformer 6
Quiz

3. INTRODUCTION OF TRANSFORMER Self inductance Mutual inductance
Electrical device that transfers electrical energy from one
circuit to another
Made up of two electromagnetic coils
Self inductance
Mutual inductance
Only operate with AC or DC that is constantly changing

4. 2.0 BASIC CONSTRUCTION OF A TRANSFORMER
Consist of 2 conductor wound around a core as shown in Figure 1.2.1
Figure 1.2.1
Core is wounded with insulated copper conductor with specific number of turns

5. 2.1 CORE
Constructed by : laminated sheets of silicon steel insulated from each other
:soft iron , powdered iron and ferrite
Thickness of the laminated sheets : between 1mm – 5 mm
Charecteristics : robust , low hysteresis
Made up of thin layers (Avoid power loss by the build-up of eddy currents )
Two major construction of the core of transformer
Shell-type form ( E-I)
Core-type form (U-I)

6. 2.2 WINDINGS Transformer consist of 2 kind of windings around the core
Winding that is connected to the voltage source ( primary winding )
Winding that is connected to load circuit and is the output path for the transformer ( secondary winding )
In an auto transformer , one winding serves as both the primary and secondary winding . The secondary winding is tapped from the primary winding
Types of winding methods :
Common winding
Coupling winding

7. TYPES AND SYMBOLS OF TRANSFORMERS
Transformer Name
Air-core Transformer
Iron-core Transformer
Iron
Powder-core Transformer
Auto Transformer
Centre-tapped Transformer
Multiple Winding Transformers
Types Of Core
Air-core
Iron-core
Powdered
Symbol

8. BASIC OPERATION OF TRANSFORMERS
3.1 WINDING RATIO
Ratio of number of turn in the primary winding to the number of turn in the secondary winding
winding ratio , n = 𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒕𝒖𝒓𝒏𝒔 𝒊𝒏 𝒕𝒉𝒆 𝒑𝒊𝒎𝒂𝒓𝒚 𝒘𝒊𝒏𝒅𝒊𝒏𝒈 𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒕𝒖𝒓𝒏𝒔 𝒊𝒏 𝒕𝒉𝒆 𝒔𝒆𝒄𝒐𝒏𝒅𝒂𝒓𝒚 𝒘𝒊𝒏𝒅𝒊𝒏𝒈 = 𝑵 𝟏 𝑵 𝟐
Step up transformer : number of turns in secondary winding exceed the number of turns in the primary winding
Step down transformer : number of turns in primary winding exceed the number of turns in the secondary winding
Isolation transformer : same number of turns in primary and secondary winding

9. 3.2 VOLTAGE RATIO 3.3 CURRENT RATIO
Ratio between the primary voltage , V1 and the secondary voltage V2 is called the voltage ratio of a transformer
Formula of voltage ratio : 𝐩𝐫𝐢𝐦𝐚𝐫𝐲 𝐯𝐨𝐥𝐭𝐚𝐠𝐞 𝐬𝐞𝐜𝐨𝐧𝐝𝐚𝐫𝐲 𝐯𝐨𝐥𝐭𝐚𝐠𝐞 = 𝐕 𝟏 𝐕 𝟐
Voltage ratio is related to the winding ratio.
Formula of voltage ratio : 𝑽 𝟏 𝑽 𝟐 = 𝑵 𝟏 𝑵 𝟐 = n
3.3 CURRENT RATIO
When AC supply is connected to transformer’s primary winding , the existing flux around the winding produces self – induction
Flux shifts to secondary winding through the transformer core to produce inductance at the secondary winding
This indicates the emf at the secondary winding is equivalent to the emf of the primary winding

10. LOSS AND EFFICIENCY OF TRANSFORMERS
4.1 IDEAL TRANSFORMERS
An Ideal Transformer is an imaginary transformer which does not have any loss in it, means no core losses, copper losses and any other losses in transformer. Efficiency of this transformer is considered as 100%.
4.2 NON-IDEAL TRANSFORMER
We can replace a nonideal transformer with an idealized transformer by including a lumped resistance equal to the winding resistance of series with each winding
The efficiency is less than 100% because power losses in corand its primary windings.
Power loss : iron & copper

11. 4.3 TRANSFORMER EFFICIENCY
For an ideal transformer, the power received by the load is equivalent to the power transferred by the primary winding
Non-ideal transformer does not reach 100% efficiency because there is power loss that is unavoidable in the core and winding
By choosing an optimum size for your winding wire and designing a suitable core that reduces iron loss to minimum, up to 99.5% efficiency can be achieved
Transformer efficiency, 𝒏= ( 𝒐𝒖𝒕𝒑𝒖𝒕 𝒑𝒐𝒘𝒆𝒓 ) 𝒊𝒏𝒑𝒖𝒕 𝒑𝒐𝒘𝒆𝒓 𝒙 𝟏𝟎𝟎%
Non-ideal transformer ,𝐡= 𝐨𝐮𝐭𝐩𝐮𝐭 𝒑𝒐𝒘𝒆𝒓 𝐩𝐨𝐰𝐞𝐫 𝐥𝐨𝐬𝐬 + 𝐨𝐮𝐭𝐩𝐮𝐭 𝒑𝒐𝒘𝒆𝒓 𝒙 𝟏𝟎𝟎% OR 𝒏= 𝑰 𝟐 𝑽 𝟐 𝒄𝒐𝒔 𝜽 ( 𝑷 𝒄𝒐𝒑𝒑𝒆𝒓 + 𝑷 𝒊𝒓𝒐𝒏 ) + 𝑰 𝟐 𝑽 𝟐 𝒄𝒐𝒔 𝜽 𝒙 𝟏𝟎𝟎%
V2 = Output voltage or secondary voltage I2 = Secondary current
Cos = power factor at the load P copper = copper loss
P iron = iron loss

12. 5.0 APPLICATION OF POWER TRANSFORMER
The most important uses and applications of a transformer are:
It can rise or lower the level of level of Voltage or Current
It can increase or decrease the value of capacitor, an inductor or resistance in an AC circuit.
It can act as an impedance transferring device.  
It can be used to prevent DC from passing from one circuit to the other. 
It can isolate two circuits electrically

13. QUIZ CHECK ANSWER SCHEMES
By referring to the figure , calculate the winding ratio of the transformer .
Answer : 4:3
2. A step up transformer as shown in figure below has a turns ratio of 1:4 and is connected to a voltage source of 240 V , 50 Hz . Calculate :
The secondary voltage
The numbers of turn in the secondary winding if the number of turns in the primary winding is 480
Answer : a) 960V b) 1920
CHECK ANSWER SCHEMES

14. 3. Figure shows a transformer with a turn ratio of 3:2 is connected to a 240V voltage source . If a resistive load of 1Ω is connected to the terminal of the secondary winding , calculate the quantities below : a)Secondary voltage b)Secondary current c)Primary current Answer : V2 = 160V , I2 = 0.16A , I1 = 0.11A 4. A 20kVA transformer with 0.8 power factor has a power loss comprising of 400W iron loss and 600W copper loss . Calculate the efficiency of the transformer operating at (a) full load (b) half load Answer : a) 94.1% b) 91.95% CHECK ANSWER SCHEMES

15. THE END HAPPY LEARNING !