Electrotherm (India) was established in 1983 in pursuit of offering custom built melting solutions to developing

Indian Steel Industry. Over the years, Electrotherm has created state-of-the-art manufacturing complex consisting

of machine shop, assembly shops and testing facilities required for its range of products. Electrotherm meets the

most stringent quality standards and offers the latest technology and process.

Electrotherm has its presence at more than 36 places in India and nine places abroad (Bangladesh, China, Iran,

Malaysia, Pakistan, South Africa, Brazil, Argentina, and Turkey) with qualified and experienced sales and service

engineers who are available round the clock to the customers. Besides back up engineers, there is a host of

metallurgists as application engineers who assist customer in cost effective manufacturing end products.

Back born of Electrotherm is its world class in-house Research and Development facility accredited by Dept. of

Science & Technology, Govt. of India, for product development, design and engineering. Elctrotherm manufactures

complete range of metallurgical equipment for Alloy Steel and Stainless Steel plants.

We produce transformers of highquality and reliability, designed to satisfy varied applications andsophisticated technical requirements.

TRANSFORMER MANUFACTURING RANGE

Standards

Our Transformers are designed, manufactured and tested to comply with various standards including IS, IEC, BS, ASTA, or any standards as specified by Customer

Converter Transformers and Induction Furnace

Arc Furnace Transformers

K-factor Transformers

System Grounding Transformers

Scott-T connected Transformers

Zig-zag transformers

Gas / Air cushioned transformers

Unitised / Packaged sub-stations

Distribution Transformers

Power Transformers

Booster / Regulating / Auto Transformers

Trasnformers Upto 25 MVA, upto 33 kV

Upto 30 MVA, upto 66 kV

Upto 25 MVA, upto 33 kV

Upto 33 kV

Upto 15 MVA, upto 33 kV

Upto 2500 kVA, 33 kV

Upto 63 MVA, upto 132 kV

Upto 63 MVA, upto 132 kV

CONSTRUCTION

The core is built from prime grade, low loss, non-aging, CRGO steel laminations. These are in conformance to latest standards for various characteristics like freedom from scale, degree of waviness, brittleness, tolerance on thickness, permeability and inherent loss due to hysteresis & eddy current. Core is of step-lap construction with mitred joints to reduce no-load losses. Adequate cooling ducts with directed oil flow are provided for cooling of core without affecting the flux distribution.

Top and bottom yoke clamps are secured to each other by tie rods. Core columns are generally strongly fastened using high resistant yoke banding.

Insulation between the core and the clamping structure is tested at 2500 volts before the windings are assembled. The core is bonded to the clamping structure and to the tank to ensure effective earthing.

Resultant rugged structure has low loss, low magnetization current and low sound level.

Windings are designed to meet electrical, thermal and mechanical requirements. Windings are manufactured with electrolytic copper conductors of maximum purity. Windings are cylindrical in shape. Depending on the voltage and current, transformer windings can be helical, continuous or interleaved disc, spiral, cross-over coils.

Windings are wound with adequate bracing and securing tapes so as to achieve strong structure. Interlayer cooling ducts are provided to limit the temperature gradient between windings and oil. This helps in limiting the hot spot temperature and minimizes the insulation deterioration.

Transpositions are made in multiple conductor windings so as to achieve uniform current distribution and to minimize circulating currents.

Before assembly onto the core, windings are pre-shrunk to a pre-determined shrinkage force to ensure better short circuit withstand capability.

Windings

Core

Tank

The tank is made of welded steel sheets and reinforced structure. Structural base is designed to permit skidding or rolling in either direction. Transformers are provided with bolted removable lid and appropriate inspection access. Where required, LV outlet on tank is fitted with non-magnetic plates.

All tanks are pressure tested after their fabrication.

Tanks are cleaned and shot blasted. Internal surface is painted with hot oil resistant coating. External surface is painted as per Electrotherm (adopted from best paint practices) procedure. Exterior paint shade is to Customer's specification.

Cooling is effected by tank mounted radiators or by means of corrugations on the tank side or by separately mounted cooling units. Cooling arrangement provided will be decided based on size of the transformer and customer specifications. If required, air blast fans, forced oil circulation employing oil pumps, or water-cooled heat exchangers can be supplied by us.

The insulating system is designed to get dielectric efforts uniformly distributed through it.Insulation between windings of different voltages is obtained through board barriers. Oil channels are included in solid insulation to enable heat evacuation.

Tapping and phase leads are brought away from the windings by means of paper covered conductors. The phase leads are separated from the tapping leads by adequate barriers. Leads are well supported to ensure adequate clearances between the leads and the tank sides upon lowering of core-coil assembly in the tank.

Whole active part is dried out with temperature and vacuum. Period is determined by the electrical tests. Oil dielectric properties are controlled before allowing its entrance to the transformer tank.

Insulation, core & coil assembly, and impregnation:

CONVERTER DUTY / FURNACE / K-FACTOR TRANSFORMERS: OUR SPECIALITY

Harmonics generated by Thyristor or Diode bridge increase the dielectric and mechanical stresses.

Frequent short-circuit like conditions, Rapid and large load fluctuations.

Avoiding structural heating due to very high current on secondary side by mounting secondary terminals on large

insulating plates.

Operational over-voltages due to frequent switching.

Double tier (HV and LV windings in two levels) for 12 pulse.

Additional phase shift windings for Pulses higher than 24.

Regulating / Booster transformer as per site and transport suitability (built into same tank or into a separate tank).

An earthed screen installed between primary & secondary windings.

Cooling options ONAN, ONAF, OFWF or any appropriate to meet application need.

Transformers designed and manufactured in accordance with the technical specifications and special requirements

stated by the associated Converter supplier.

Design considerations are incorporated in design for

A wide spread Customer Support Network to

provide Installation, Commissioning or

maintenance support.

Highly skilled manpower.

Latest manufacturing and testing facility.

Effective Quality assurance Plan for incoming

material and for in-process.

Customized terminal arrangement ranging

from bus ducts, cable boxes and bare

bushings.

THE ET ADVANTAGES

TESTS

Before dispatch, all the transformersare subjected to routine tests inaccordance with relevant standard.

Following special tests can be performed atour works

Capacitance Tan Delta test

Measurement of zero sequence impedance

Measurement of Noise Level

Measurement of No Load Harmonics

Measurement of power taken by fans and pumps

72, Palodia, (Via Thaltej), Ahmedabad- 382 115, Gujarat (INDIA).Ph: +91-2717-234 554, 660550. Fax: +91-2717-234 616,E-mail: mkt@electrotherm.com, tinfo@electrotherm.com, ettransformers.comWebsite: www.electrotherm.com

Customer Name KV ClassRating

Hans Ispat

Hans Ispat

Welspun Steel and Power

Welspun Steel and Power

MITC Rolling Mill

Surbhi Steel

Saptashrungi Alloys

Veer Gurjar Industries

Rohit Ferrotech

Mahashivshakti Steel

S.P. Ispat

Kirloskar Brothers

11/0.750 KV X 4, 24 Pulse

11/11 KV

33/0.750 KV X 4, 24 Pulse

33/33 KV

33/0.750 KV X 4, 24 Pulse

33/0.600 KV X 4, 24 Pulse

33/0.600 KV X 4, 24 Pulse

33/0.850 KV X 3, 18 Pulse

33/1.000 KV X 2, 12 Pulse

33/0.500 KV X 4, 24 Pulse

33/0.850 KV X 2, 12 Pulse

11/0.850 KV X 2, 12 Pulse

20 MVA

20 MVA

17 MVA

17 MVA

15 MVA

12 MVA

10 MVA

6.75 MVA

5.5 MVA

5.5 MVA

4.25 MVA

2*2.1 MVA