A REPORT ON OUR VISIT TO UTTAM TRANSFORMERS

1. INDUSTRIAL VISIT REPORT- UTTAM
TRANSFORMERS
Departmentof Electrical Engineering,PoornimaCollege of Engineering organized an industrial visit
on 25th
March 2017 to Uttam (Bharat) Electricals Private Limited, addressed at B-189/A, Road No.
9(F), Vishwakarma Industrial Area, Jaipur for students of the Branch. The visit was organized with
priorpermissionandguidance of Dr.VirendraSangtani,Headof Department.Total40studentsalong
with faculty members Mr. Rohit Sharma and Mr. Amba Lal as coordinators visited the same.
We started from the college at 9:15 AM. and it took us approximately two hours to reach our
destination via College transport.
The main objective of the visitwastoknow theoretical termswithindustrial(practical) exposure and
working of Uttam Transformers.
An engineer at Uttam transformers welcomed all of us at the entrance and took us in batches to
explain the manufacturing process and working of Transformers in detail.
COMPANY PROFILE:
Uttam Bharat) Electricals Private Limited is an ISO 9001:2008 certified leading manufacturer of
PowerandDistributionTransformers from 5KVA to 12500 KVA upto 11-22-33 KV class, Single-Three
Phase having a turnover of approx. 112 crores.
The company hasmachine facilitiestoDesign,Manufacture andtestTransformersasperIS:2026/BS-
171/IEC-76 international standards.Transformersupto12500 KVA rating33 KV classhave beentype
tested for Short circuit and Impulse test at CPRI and other government approved laboratories.
The company has received SE2B rating by CRISIL which denotes high performance capability
adjudged in relation to other SSI’s.
The company has been meeting specific requirements such as dual-ratio transformer, Furnace
transformers, Transformers with OLTC or conversion of existing transformer to any voltage ratio.
Uttam transformers have developed and supplied fail safe Distribution transformers, wound core
transformers and are in the process of developing Amorphous core, and Dry type transformers.
Uttam made transformers are approved by Telecom, CPWD, MES, Railways, PWD and various
utilities ans state electricity boards.In a span of over 30 years, the company has supplied over
1,50,000 Power and Distribution transformers at various ratings and voltages to users in India and
Abroad. The company has exported transformers to Jordan, Nigeria, Bhutan, Sri Lanka and Nepal.
The salient features of the company include Robust Design, Economical losses, Stringent Quality
control,timelydelivery,extendedguarantee period,efficientandpromptaftersalesservice. We
were explained the following details about transformers:

2. There are two types of circuits in a transformer-
 Magnetic circuit (core)
 Electric circuit
Basic Parts of a Transformer:
1) Laminated core
2) Windings
3) Insulating Materials
4) Transformer oil
5) Tap changer
6) Conservator
7) Breather
8) Cooling tubes
9) Buchholz Relay
10) Explosion vent
Core:
The core is used to support the windings in the transformer.
Cold-rolledgrain-oriented(CRGO) steel is used for the manufacture of transformer core.It has low
magnetichysteresislooparea,whichminimizes magneticlosses&highsiliconcontentwhichleadsto
high resistance, decreasing eddy current losses. So, overall losses are reduced.
Amorphous Core: Amorphous core material offers both reduced hysteresis loss and eddy current
lossbecause this material has a random grain and magnetic domain structure which results in high
permeability, which ensures a narrow hysteresis curve compared to conventional CRGO material.
The thickness of Amorphous sheet is about 1/10th
that of CRGO.
Core Assembly:
It consists of:
1) Core made up of CRGO steel.
2) Core bolt
3) Three limbs
4) Top Yoke and Bottom yoke
5) Tie rod
6) LT & HT Windings
WINDINGS:-
LT Windings are connected in star and HT Windings are connected in Delta.

3. Enamel isusedto insulate the windingsof low voltagetransformers. For power transformers, paper
insulation is used for winding wire as well as in the form of strips of paper insulation between
winding layers.
Cross winding-
It is made of circular conductor used for High voltage windings of relatively small transformers.
Helical winding:
We use helical winding where we need to draw more current.It consists of large no. of parallel
conductors piled in the radial direction and wound. It is used for windings of low voltage(20 KV or
below) & large current.
Between layers, no insulation other than conductor insulation is required as voltage between the
layers is low.
The parallel circuits bring in the problem of current sharing.Transposition is adopted to reduce
unequal current distribution. The modern trend is to use transposed and bunched conductors.
MS Tank
Mild Steel Tank consists of three phase windings along with Neutral.
It is filled with Transformer oil.
Gasket- Oil seal is used to prevent any leakage.
TRANSFORMER OIL:-
ON-AN (Oil Natural Air Natural) transformers have inbuilt properties of cooling down oil inside it.
ON (Oil Natural)- AF (Air Force) Transformers have to be provided with external air force to cool
down the temperature.
OVEN:
Core assembly is heated in the oven.
Conservator Tank:
It is placed on the Mils Steel Tank and is filled with Transformer Oil.
Breather Pipe:
It is used to carry moisture-free, dry air into the tank.
Equalizer Pipe- It is used to equalize pressure.
The expected life of a transformer is 20-25 Years.

4. Testing Lab is used for the Health check of the transformers.
Tap No. PT Ratio
1 600/600
2 1200/600
3 1800/600
4 2400/600
5 3000/600
MarshallingBox:Itis a weather-proof terminal box which connects the transformer’s fittings to the
protective schemes to give alarm under abnormal conditions.
It also houses Oil temperature indicator (OTI) and Winding temperature indicator (WTI).
Buchholz Relay:
It is connected between the Conservator tank and Transformer tank.
Explosion vent pipe:
It is the top-most and weakest part of the transforer to ensure transformer protection. A very thin
brass metal is used which breaks if there is any fault in the transformer.