A transformer is a device that changes alternating current (AC) electric power from one voltage level to another. It consists of two coils wound around an iron core, and works through electromagnetic induction. Transformers are necessary in power systems to increase voltage for efficient long-distance transmission, and then decrease voltage for safe distribution and usage. They allow power to be transmitted at high voltages to reduce transmission losses, then stepped down for domestic and industrial use.

1. UNIT-II
TRANSFORMER
P.MARIA SHEEBA
AP/ECE
MZCET

2. 2.1 Introduction to Transformer.
 Transformer is a device that changes ac electrical power at
one voltage level to ac electric power at another voltage
level through the action of magnetic field.
Block Diagrams of Transformer.
2

3. 1.2 Applications of Transformer.
Why do we need transformer?
The Power Grid
3

4. 1.2 Applications of Transformer.
Why do we need transformer?
(a) Step Up.
In modern power system, electrical power is generated at
voltage of 12kV to 25kV.
Transformer will step up the voltage to between 110kV to
1000kV for transmission over long distance at very low lost.
The Power Grid
The Transmission Tower
4

5. 1.2 Applications of Transformer.
Why do we need transformer?
(b) Step Down.
The transformer will stepped down the voltage to the 12kV
to 34.5kV range for local Distribution.
In homes, offices and factories stepped down to 240V.
The Power Grid
The Substation
The Utility poles
5

6. .
A transformer is a device for increasing or decreasing an ac voltage.
Introduction2.1
MZCET/ECE/III Sem/EE6352- Unit 2 6

7. • A transformer consists of a primary coil and a
secondary coil, both wound on an iron core.
• The changing magnetic flux produced by the
current in the primary coil induces an emf in
the secondary coil.
Introduction2.1
MZCET/ECE/III Sem/EE6352- Unit 2 7

8. • A transformer is a
device that changes ac
electric power at one
voltage level to ac
electric power at
another voltage level.
Introduction2.1
MZCET/ECE/III Sem/EE6352- Unit 2 8

9. 1. Transfers electric power from one circuit to
another
2. It does so without a change of frequency
3. It accomplishes this by electromagnetic
induction
Introduction2.1
MZCET/ECE/III Sem/EE6352- Unit 2 9