RANGE : Upto 10,000 KVA in 11 & 33 KV Class.

We offer HT Distribution transformers/Industrial Transformers which comply with major industrial norms IS2026, BS -171, IEC-76 and IEC 726. These are available with bare bushing or cable box and disconnecting chamber can also be added. These products can handle a maximum oil temperature rise of 55 degree C. The core comprises of CRGO Sheets with annealed Laminations. The coils are winded with electrolytic high quality paper and the tanks are made up of M.S. steel. Tapping tolerance is +5% to -5% and can be customized as per client request. Quality Oil is used after various testing to maintain required dielectric character.

Following are the tests that are carried out on our distribution & power transformers:
»
Turns ratio test
»
Insulation resistance test
»
No load losses measurement
»
Polarity & phase relationship test
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Impedance voltage test
»
Resistance measures of winding
»
Short circuit test
»
Leakage test of transformer tank
»
Dielectric test

 

Technical specifications

Ratings

Upto 10000 KVA

Applicable Standards

IS, IEC, BS etc.

Cooling

ONAN, ONAF

Insulating Fluid

Mineral Oil to specification

Frequency

50 Hz, 60 Hz

Polarity

As specified

Primary voltage

11Kv/ 22 Kv/ 33 kV

Secondary Voltage

433 v (As required)

Winding material

Copper

Taping

On Load Tap Changer to provide +5% to -15% Taps in steps of 1.25% on the H.T. Side. Else, Off Circuit Tap Changer for ± 5% Taps on H.T. Side in steps of 2.5% each.

Impedance

In line with applicable standards

Insulation

Class 'A' (as required)

Vector Group

DYN 11

 

Features
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Strict quality measures & testing standards
»
Optimum efficiency
»
Proportioning of core and winding losses using CRGO M3 to MS MOH lamination
»
Electrolyte Grade 99.9% pure copper
»
Transposition in L.V. coil for current sharing in parallel conductors
»
Low temperature rise
»
Low maintenance cost

 

Application
The distribution & power transformers have their prime use for converting high voltage current to low voltage current with no change in frequency. These transformers are widely used in:
» Suburban areas
» Industries
» Power supply authorities
Standards:
HMI® brand HT & LT transformers are designed and tested as per IS : 2026, BS-171, IEC-76 & IEC-726.
Terminal arrangement:
H.V - Bare Bushings or Cable Box, L.V Bare Bushings or Cable Box. Disconnecting chambers can also be provided on both HV and LV request.
Temperature rise:
HMI® brand HT & LT transformers are designed for a maximum temperature rise of 50/55 °C of oil/winding. Lower temperature rise can be offered on request.
Core:
The core is constructed from low loss, cold rolled, grain oriented, annealed lamination of electrical sheet conforming to the latest international standards. Special frame is built in-house for clamping the core to reduce the magnetic noise as well as making the whole structure rigid and robust.
Windings:
Coils are wound with electrolytic high conductivity paper covered or synthetic enameled copper conductors. Cooling ducts are provided to keep the hot spot temperature as low as possible. Coils are dried in electric ovens. Rigid connection support and coil clamping is provided to ensure high short circuit strength.
Insulation:
Pre-compressed board PARMALI board and JAPANEESE insulation paper of best quality is used.
Tappings:
Off circuit tap changing switch
Tapping from+ 5% to -5% in steps of 2.5% for HV variation of as per customer's requirement.
On load tap changer
Tapping range as per specific requirements can be offered. OLTC for remote/auto/parallel operation can also be offered.
Oil:
Oil is tested for resistivity, dielectric and acidic characteristic conforming to IEC-296j/IS-335. Before topping up, oil is filtered thoroughly.
Tanks:
The Tanks are made of M.S. Steel palter/sheets with adequate bracing & stiffeners. Tanks are pressure tested to withstand any type of inside or outside pressure. All the external surfaces are given a primary coat of zinc chromate, red oxide and two finishing coats of grey paint. The inner surfaces are given a coat of heat and oil resisting paint.