single phase transformer

1. DEPARTMENT OF ELECTRICALAND ELECTRONICS ENGINEERING
TECHNICAL SEMINAR
DESIGN OF SINGLE PHASE TRANSFORMER
PRESENTED BY
V.RAHUL
2065FA0206

2. DEFINITION AND FEATURES OF TRANSFORMER
 Definition:-
 It is a static device transfer power from one circuit to another
circuit .
 Features:-
 It is a constant frequency device.
 Constant power device .
 It is a constant flux device .
 It is a 180 degree phase shift
 It is an electromagnetic energy conversion device(internal energy
conversion).

3. CONSTRUCTION OF TRANSFORMER
We have mainly two parts.
1. Transformer core.
2. Transformer winding.

4. 1-PHASE TRANSFORMER.

5. TRANSFORMER CORE
 Low reluctance.
 High permeability.
 Feromagnetic material.
 Low iron loss.
‘si’ steel iron+carbon=steel
By adding 4% to 5% of silicon
Silicon Steel

6. HOW SHOULD BE THE CORE
 Consider a solid core.
 The current carrying capacity is
depend the cross sectional are of
conductor.
 Eddy current losses takes place in
the form of heat.
 Due to induced emf in the core eddy current flows(Ie)
 Each and every material offers some amount resistance.
 So, finally due to this Ie^2Rc losses produces. (Rc= Core resistance)

7. CONSIDER A LAMINATED CORE.
 In order to over come the drawbacks of solid core we need to
make the laminations.
 Cros sectional area of the core is reduced.
 Insulating medium is oxide paint, chaina clay, Japan varnish.

8. SHAPE OF SILICON STEEL
 Crystal structure called BCC –(BODY CENTRE CUBIC
STRUCTRE)
 In silicon steel we have lakhs of cubes/grains.
 This are all microscopic pictures.

9. EDGES AND DIAGONELS
In this cubic structure we have edges and
diagonals.
12-Edges.
04-Diagonals.

10. CONSIDER DIAGONAL PATH
Diagonal is the shortest path .
But to air gap it offers high reluctance path.

11. CONSIDER A SMALL PIECE OF SILICON STEEL
Normal silicon steel:
 There is non-orientation of cubes/grains.
 As compare to the length of the silicon material, the flux
is taking more length of the path.

12. DRAWBACKS OF SILICON
 Due to increase in length of the flow of flux.
 Reluctance of the steel little increases.
 But compare with any other material silicon is
best(offers low reluctance path to magnetic
flux).
 We can reduce the reluctance further .
 By converting non-oriented grains into oriented
grains.

13. PROCESS TO COVERT NON- ORIENTED GRAINS
INTO ORIENTED GRAINS
 In Mechanical Engineering we have two
process.
1.Hard Rolling Process.
2.Cold Rolling Process.
 In order to achieve orientation of
cubes/grains we need to go for cold rolling.

14. Cold Rolling Process
 The cold rolling process is performed under some
temperature and pressure.
 As compare to hard rolling process it is very low
(60degrees to 100degree Celsius).

15. Conclusion
 By the cold rolling process the silicon steel is
converted into cold rolled grain oriented steel
(CRGO STEEL).
 As path of flux is reduces .
 Reluctance is reduced.
 Reduced losses.
 Higher efficiency.

16. Thank You