A transformer transfers energy between two circuits through electromagnetic induction. It has a primary winding connected to an alternating current source and a secondary winding connected to a load. The number of turns in each winding determines the ratio of voltages induced. If the secondary winding has more turns than the primary, it is a step-up transformer and increases the voltage. If the secondary has fewer turns, it is a step-down transformer and decreases the voltage. Transformers operate by inducing voltages in each winding through a changing magnetic field created by the primary current in the transformer's core.

1. Mehran University
Of Engineering & Technology,
SZAB Khairpur Mirs Campus
Mehran University
Of Engineering & Technology,
SZAB Khairpur Mirs Campus
TRANSFORMER

2. INTRODUCTION
 A transformer is an electrical device that transfers energy between
two or more circuits through electromagnetic induction.
 A varying current in the transformer's primary winding creates a
varying magnetic flux in the core and a varying magnetic field
impinging on the secondary winding.
 This varying magnetic field at the secondary induces a varying
electromotive force (emf) or voltage in the secondary winding.
 Making use of Faraday's Law in conjunction with high magnetic
permeability core properties, transformers can thus be designed to
efficiently change AC voltages from one voltage level to another
within power networks.
 transformers have become essential for the AC transmission,
distribution, and utilization of electrical energy.
 The winding connected to the a.c. source is called primary winding
(or primary) and the one connected to load is called secondary
winding (or secondary).
 The alternating voltage V1 whose magnitude is to be changed is
applied to the primary.

3. Depending upon the number of turns of the primary (N1) and
secondary(N2), an alternating e.m.f. E2 is induced in the secondary.
This induced e.m.f. E2 in the secondary causes a secondary current I2
Consequently, terminal voltage V2will appear across the load.
 If V2> V1 , it is called a step up-transformer.
On the other hand, if V 2< V1 , it is called a step-down transformer.

4. WORKING PRINCIPLES
 When an alternating voltage V1 is applied to the primary, an
alternating flux is set up in the core.
 This alternating flux links both the windings and induces
e.m.f.s E1and E2 in them according to Faraday’s laws of
electromagnetic induction.
 The e.m.f. E1is termed as primary e.m.f. and e.m.f. E2 is
termed assecondary e.m.f.

5. CONSTRUCTION

7. Ideal Transformer On No Load
An ideal transformer is one that has
(i) no winding resistance
(ii) no leakage flux i.e., the same flux links both the windings
(iii) no iron losses (i.e., eddy current and hysteresis losses) in the core

10. Ideal transformer on load

12. PRACTICAL TRANSFORMER ON NO LOAD

14. PRACTICAL TRANSFORMER ON NO LOAD
I)TRANSFORMER WITH NO LEAKAGE AND RESISTANCE LOSSES

16. II)TRANSFORMER WITH LEAKAGE AND RESISTANCE LOSSES