This document summarizes the summer training completed by Shashank Bhadouria at Crompton in Jaipur from June to July 2022. The training covered the manufacturing process of distribution transformers including preparing the core from CRGO steel sheets, winding the low and high voltage coils, insulating and assembling the core and coils, filling the tank with oil, and performing quality control tests. The objectives were to apply theoretical knowledge, observe the manufacturing process, and develop career skills relevant to distribution transformers.

1. Birla Institute Of Technology
Mesra , Jaipur Campus
SUMMER TRAINING
[1st June – 28th July 2022]
Name- Shashank Bhadouria
EEE-VII -SEM

2. Contents…..
⮚ Objective
⮚ Company Profile
⮚ Basic Theories
⮚ Working Principle of Transformer
⮚ Distribution Transformer
⮚ Oil immersed distribution Transformer
⮚ Manufacturing of 3-Phase Distribution Transformer
⮚ Recommendations

3. objeCtives…..
⮚To apply theoretical knowledge in the practical field
⮚ To observe the manufacturing process of distribution transformer, testing
⮚Collecting knowledge regarding distribution transformer
⮚Developing skills and techniques relevant to our careers

4. Company profile….
⮚ Name: Crompton
⮚ Factory location: DLF Phase III, DLF Cyber City, DLF Phase 2, Sector 24, Gurugram,
Haryana
⮚ Ownership: Crompton Greaves Consumer Electricals Limited

5. Working Principle of
transformer….

6. Distribution
transformer…..
⮚ Used for distribution of electrical energy
⮚ Generally, operates at low voltage as less than 33KV in
industrial purpose and 440v-220v in domestic purpose
⮚ Three phase distribution transformers ,widely used in
11kv distribution
line to step down the voltage level.

7. Basic Theories..
7
1. Transformer is an electrical device that
transfer electric power from one circuit to
another
2. It does so without a change of frequency
3. It accomplishes this by electromagnetic
induction
4. Where the two electric circuits are in
mutual inductive influence of each other

8. oil immersed distribution transformer….

9. Manufacturing of 3-Phase
Distribution Transformer

11. ⮚ Active Part :
The ferromagnetic core
and windings

12. Transformer manufacturing proCedures….

13. Core material….
⮚ The mostly used core
material is CRGO-Cold
Rolled Grain Oriented steel
sheets of 3% of Silicon
⮚ Thickness of the CRGO
sheets usually 0.27 mm
⮚ Oxide coating is provided
for CRGO laminations to
reduce eddy current losses

14. Core Cutting….
Straight type core cutting

15. Core jointing on Channel….
⮚ This is the simplest form of joints
⮚ The flux leaves and enters at the joint in
perpendicular

16. ⮚ Placing laminated sheets by hand or
hammer manually
⮚ No air gap between the joints of two
consecutive sheets
⮚ The entire assembly is done on a frame
commonly known as core channel
⮚ These frames being used as a clamping
support of the core assembly

17. Covering Copper wire with insulating tape…..
⮚ The mostly used
material for winding
wires or strips is
copper .
⮚ The copper wires or
strips are wrapped by
insulating tape or DPC
paper.

18. low voltage windings…..
Vertical machine is used to prepare the
LV winding
The helical and double layers
Number of turns varies on KVA
rating

19. low voltage windings…..
Starting End
Finishing End
Gape between two layers
⮚ Greater simplicity in fitting
cooling ducts
⮚ More even heat
distribution through the
windings

20. high voltage windings….
⮚ Horizontal machine is used to prepare the
HV winding
⮚ HV windings are of layered construction
⮚ The conductors are made of more round
wires, either with an insulating paper
⮚ The insulation between the layers
consists of DPC paper

21. high voltage windings…..

22. Contd.
Insulation between two layers :
Insulation between two layers of
DPC paper

23. Core-Coil assembly…..
Opening the upper yoke

24. Insulating between core and LV
winding
Cotton tape
Press board
Contd.

25. Placement of LV
Winding:
⮚ The LV windings in the
core limb .
⮚ They are fitted tightly in all
three limb using pressed board.
Contd.

26. Contd.
Press Board Cutting DPC Paper
Isolating HV from LV
winding:

27. Contd.
Before inserting the HV winding

28. Placement of HV
Winding:
Contd.
⮚This coil is placed on LV winding as
second layer of core
⮚ First LV coil then HV coil
⮚The gap between the LV and HV coil
is filled with runner of pressed board

29. ConneCtions…..
HV Side ( Delta Connection) LV Side (Star
Connection)

30. Contd.

31. Vector grouping.....
The vector grouping in NEL is Dyn
11:
⮚ Delta connected HV winding
⮚ Star connected LV winding
⮚ Neutral brought out
⮚ LV is leading HV with 30°
(11 o’clock)

32. taap Changer…..
⮚ Tapping is terminated
just bellow oil level
⮚ External
handle
⮚ Taping is done on HV
winding
⮚ Used to regulate the
output voltage to
required levels
Tap Changer
Exterrnal Handle

33. Taping Wires
Connected to HV
coils
Changer
How Tapping done:
p
e

34. moisture Control…..
⮚ The whole active part of the transformer
in the heat chamber
⮚ Keeping it there for 72 to 96 hours with
a continuous heating temperature of
100° - 141° C to clean the moistures in it
⮚ Bringing it out after getting proper
insulation

35. the tank…..

36. Functions of Transformer Tank...
⮚ A container for the cooling
liquid
⮚ Providing shielding
against electromagnetic
field leakage

37. radiator….
⮚ Made steel like
tank
⮚Attached with the
tank
⮚Radiate the heat
from insulating oil
and makes the oil
cool

38. inserting the aCtive part into the tank…..
⮚ Whole active part is covered by
press board
⮚ Crane is used to lift the active part
⮚ By handling a chain the active part
is put slowly in the tank

39. bushings….
⮚ Counteracting the electrical field
strength
⮚ Insulating the incoming or outgoing
conductor into or out of the transformer
tank
Conductor
Insulator

40. Conservator….
⮚ Providing adequate space for
expansion of oil inside the tank
⮚ It also acts as a reservoir for the
insulating oil.
⮚ The oil level indicator indicates the
oil level
⮚ Oil level should not fall below
minimum limit

41. filling oil…..

42. funCtion of transformer oil….
⮚ Providing dielectric strength
to the insulation system
⮚ Providing efficient cooling
⮚ Protecting of the transformer
core and coil from chemical
attack

43. QC tests….
Testing of Distribution Transformer:
⮚ Insulation test
⮚ Ratio test
⮚ Open circuit test
⮚ Short circuit test

44. Ready To Deliver..