SRI ® Make V.P.I. Dry Type Distribution Transformers << Back

Dry type transformers are those transformers that use air as cooling and dielectric medium instead of conventional technology of transformers which uses mineral oil as a cooling and dielectric medium.

Vacuum Pressure Impregnated (V.P.I.) Dry Type Distribution Transformers

V.P.I. is a process which is a step above the conventional vacuum system. V.P.I. includes pressure in addition to vacuum, thus assuring good penetration of the varnish in the coil. The result is improved mechanical strength and electrical properties. These transformers are used in installations within the building premises,crowded and urban areas,overloaded feeders, near to the load centre or even outdoors where there is oil theft.

We at Shri Ram Group Of Industries utilise a state of art vacuum impregnating system to manufacture Dry type transformers upto 3 mVA 33kV Class..

  • Technical Specifications
  • Salient Features
  • Standard Fittings
  • Optional Fittings

Technical Specifications

Rating Upto 3mVA
Duty Type Outdoor/Indoor, Ground Mounted Type& Pole Mounted Type
Voltage Class Upto 33Kv
No Of  Phases 3 phase
Frequency 50/60 Hz
Vector Group Dyn1 or Dyn5 or Drn11 or any specific
Class Of Insulation F , H Or C class as required
Insulating Material Nomex, Silicone Varnish, Fiber Glass, Glass Epoxy
Temperature Rise 65.C to 115.C above ambient temperature of 50.C by resistance method or as per customer’s requirement
Tap Changer Off Circuit or On Load
Tapping Range +-2.5% X 2 for OCTC or +-2.5% X 2 & -2.5% X6 for OLTC as per customer requirement
Winding Material Aluminum Or Copper with multi paper NOMEX covering
Applicable Standards IS 11171,IEC 60726
EnclosurePainting Powder Coated with RAL 7032 Shade or as per customer requirement
Tank Hermetically Sealed, Corrugated Type or Conventional Air cooled Type

Salient Features of SRI ® Make V.P.I. Dry Type Distribution Transformers

Pioneer and one of the biggest vendor in India.
Nomex© engineered Dry Type Transformer with an overload withstanding capability of 140%.
Environment Friendly
Non Flammable, Fire Resistant, Maintenance Free, Repairable at site.
Polyester resin or thixotropic epoxy resin or silicon varnish impregnation as per application.
“H’ class ducts between coils and discs to maximize air flow and reduce hot spot temperature.
Custom made to meet each and every requirement of customers conforming to National & International Standards.
Designed by experienced expert engineers using most modern software.
Average Delivery Time: 30-45 Days.
Facility to make 100Nos Transformers per month.


H.V. Cable Box L.V Cable Box with Bus bar or Bus duct Off Circuit Tap Links
Under carriage with four bi-directional Rollers Earthing terminals Rating diagram plate
Lifting lugs for complete Transformer Enclosure with panels Canopy
Base Channel-2 Nos. Separate Neutral bushing on LV side Paint: Powder Coated with RAL 7032 Shade
Hinged Windows for inspection of core and windings

Optional Fittings

RTD with A/T contact Marshalling box with control wiring On Load Tap Changer with RTCC Panel and AVR
Forced cooling arrangement Neutral Current Transformer Space heaters for core & windings.