Power transformer radiators
Power transformers are used in electrical transmission networks to step voltage up or down between generation, transmission, and distribution systems — typically operating at ratings from 1 MVA and above.
Prima Transfab manufactures precision-engineered radiator fins for power transformers across all ratings which are manufactured on a fully automatic production line, 100% pressure tested, and built to IEC 60076 standards.
Radiator types available
Straight type
Both inlet and outlet manifold pipes run parallel and inline with the fin body. The standard configuration for the vast majority of power transformers — simplest mounting, most common across all ratings.
Swan neck type
The outlet manifold pipe has an angular bend that offsets the connection point downward, allowing the radiator to connect to a tank port positioned lower than the fin body centreline. Used where the transformer tank design requires the bottom oil connection at a lower position. Available across all standard fin lengths and panel counts.
T-type radiators
The manifold pipe runs centrally with fins extending on both sides of the assembly. Used where the transformer tank design requires a wider cooling bank in a compact vertical space. Available across all standard fin lengths and panel counts.
Stainless steel radiators
All radiator types — straight, swan neck, and T-type — are available in stainless steel for coastal, chemical plant, or high-humidity environments. No painting required — natural corrosion resistance for the life of the transformer.
Key specifications
| Parameter | Value |
|---|---|
| Fin length | 650 mm to 4000 mm |
| Fin width | 380 mm & 520 mm standard |
| Material | Cold rolled steel (CRCA) · Stainless steel |
| Sheet thickness | 1.0+1.0 mm & 1.2+1.2 mm |
| Manifold diameter | Φ89 mm standard |
| Fins per assembly | 5 to 40 fins (custom on request) |
| Shoulder angle | 5° oblique, without rounded corners |
| Test pressure | 0.15 - 0.4 MPa (adjustable) |
| Parameter | Value |
|---|---|
| Horizontal weld pitch | 75 mm - 88 mm |
| Vertical weld pitch | 40 mm - 100 mm |
| Standard compliance | IEC 60076 • IEEMA • EN 50216-6 |
| Weld process | Resistance seam weld + TIG argon arc end weld |
| Production capacity | 75 fins/hour (2 m length basis) |
| Leakage test | 100% hydraulic pressure test, every assembly |
| Radiator types | Straight • Swan neck • T-Type • SS |
| Cooling class | ONAN • ONAF • OFAN • OFAF |
Cooling class compatibility
ONAN
Oil natural air natural — standard free convection cooling
ONAF
Oil natural air forced — with external cooling fans
OFAN
Oil forced air natural — pumped oil circulation, free air
OFAF
Oil forced air forced — pumped oil, forced air cooling
Surface finish & painting options
Primer only (no topcoat)
Primer + Paint finish - Shot blasted, fully primed, and finish-coated in a customer-specified colour. Radiator arrives ready for direct installation on the transformer tank without further painting at your end.
Primer + finish paint
Shot blasted, fully primed, and finish-coated in a customer-specified colour — typically RAL 7035 light grey or any RAL / IS standard shade. Radiator arrives ready for direct installation on the transformer tank without further painting at your end.
Hot dip galvanized
Radiators fully galvanized by hot dip process after fabrication, providing a zinc coating of 85 µm or above. Offers superior long-term corrosion protection — typically 25–40 years in normal environments without any repainting.
Internal varnish coating
The internal surface of every radiator fin assembly can be coated with a phenol-based varnish on request. This provides protection against internal corrosion and contamination during extended storage or long-distance transportation before installation. Recommended for projects where radiators will be stored for more than 30 days before mounting, or for export shipments.
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