Transformer Cooling Fan for Power Substation — Manufacturer & Supplier
Vayuvents Pvt. Ltd. manufactures and supplies transformer cooling fans for power substation applications across India and export markets.
Power substations ranging from 11kV distribution sub-stations to 400kV EHV grid sub-stations house power transformers that require forced-air cooling (ONAF) fans to operate at full rated capacity in Indian ambient conditions.
Vayuvents supplies transformer cooling fans matched to distribution transformers (100 kVA to 10 MVA) and power transformers (10 MVA to 300 MVA) in substations operated by state DISCOMs, PGCIL, and private utilities across India.
Our fans are designed for outdoor substation environments — with IP55 weatherproof motor enclosures, anti-corrosion paint systems, and frame-mount designs that attach directly to existing transformer radiator brackets without modification.
How It Works in This Application
Heat Generation in Transformer Windings
Electrical losses in the transformer core and windings heat the insulating oil circulating inside the tank — the primary heat source to be managed.
Oil-to-Radiator Circulation
Hot insulating oil circulates from the transformer tank to external fin-tube radiator banks where heat is transferred to ambient air.
Forced Air Cooling
Transformer cooling fans mounted below or beside the radiator banks force ambient air upward through the radiator fins, dramatically increasing heat transfer rate.
Continuous Capacity Operation
With ONAF fans operating, transformer capacity increases by 25 to 33 percent over the ONAN rating — allowing the substation to supply peak demand without overloading the transformer.
Recommended Variants
Standard Frame-Mount Fan
Compact axial fan in standard frame for direct mounting on transformer radiator bank channels — most common substation configuration.
Most RecommendedAuto-Thermostat Controlled Fan
Fan with integrated thermostat that activates automatically when transformer oil temperature reaches the set point — energy saving and hands-free operation.
High-Capacity Multi-Fan Array
Multiple smaller fans arranged in an array across the radiator bank face — provides redundancy if one fan fails.
High-Ambient Rated Fan
Motor rated for 50 to 55 degrees Celsius ambient for substations in hot desert and coastal locations.
Technical Specifications
| Parameter | Specification |
|---|---|
| Airflow Capacity | 500 to 20,000 m3/hr per fan |
| Motor Power | 0.04 kW to 2.2 kW |
| Fan Diameter | 200 to 800 mm |
| Voltage | 415V / 230V 3-phase and single-phase |
| Motor Enclosure | TEFC IP55 as standard |
| Blade Material | Aluminium / PP |
| Standards | IS 4894, IEC 60076 |
Key Features
- Compact direct-drive design with motor integrated in fan hub — fits standard transformer radiator mounting brackets
- IP55 TEFC motor as standard for outdoor substation and industrial installation in all weather conditions
- Low-noise operation essential for transformer substations in residential and commercial areas
- Aluminium and PP blades are lightweight and non-sparking for safe electrical equipment mounting
- Thermal protector built into motor winding protects against overheating if airflow is obstructed
- Available in 415V 3-phase and 230V single-phase for compatibility with transformer auxiliary supplies
- Long-life factory-sealed bearings require no periodic lubrication for maintenance-free operation
- Works performance test certificate with measured airflow and motor power data
Industries That Use This Application
Distribution Substations
11/0.4 kV distribution transformers in residential, commercial, and industrial area substations
Industrial Substations
33/11 kV and 66/11 kV plant substations in large industrial complexes and special economic zones
Grid Substations
132/33 kV, 220/33 kV, and 400/220 kV grid substations operated by PGCIL and state transmission utilities
Renewable Energy Substations
Solar and wind farm substation transformers requiring ONAF fans for operation at rated capacity
Railway Traction Substations
Traction transformer substations for Indian Railways 25 kV electrification — high load factor requiring ONAF cooling
Commercial Building Substations
Rooftop and basement transformers in high-rise commercial buildings with restricted natural ventilation
New Substation Projects
EPC contractor supply for new substation construction where transformer manufacturer specifies ONAF fan quantity and type
Retrofit Upgrading
ONAF fan retrofitting to existing ONAN transformers to increase substation capacity without transformer replacement
✓ Supply & Support: Vayuvents manufactures transformer cooling fans at our Vasai, Mumbai works. We supply to DISCOMs, EPC contractors, and utilities across India. We can match existing radiator bracket dimensions for retrofit supply.
FAQs
ONAF (Oil Natural Air Forced) is a transformer cooling class where the insulating oil circulates naturally but ambient air cooling of the radiators is enhanced by forced-air fans. Adding ONAF fans increases transformer rated capacity by 25 to 33 percent over the ONAN (natural cooling) rating — for example, a 100 MVA ONAN transformer can supply 133 MVA ONAF. DISCOMs use ONAF fans to increase substation capacity without replacing the transformer.
The number depends on the transformer MVA rating and radiator bank configuration. A small 1 MVA distribution transformer may need 2 to 4 fans. A 100 MVA power transformer may need 20 to 40 fans across multiple radiator banks. Vayuvents provides fan selection based on the transformer nameplate data and radiator bank layout.
Transformer cooling fans for substations are typically mounted on the lower channel of the radiator bank, with the fan blowing upward through the radiator fins. The fan frame slides into and clips onto the radiator mounting channel — no drilling or welding is required. Vayuvents supplies fans with the correct frame dimensions for all major Indian transformer manufacturers' radiator channel standards.
Yes. Transformer cooling fans are controlled by a thermostat wired to the transformer Oil Temperature Indicator (OTI) or Winding Temperature Indicator (WTI) — switching fans on when temperature reaches Stage 1 setpoint (typically 55 to 65 degrees Celsius oil temperature) and off when it falls below the reset temperature. Vayuvents can supply fans with matching control panels for automatic OTI/WTI-based operation.
Standard supply is 415V 3-phase 50Hz for fans larger than 200mm diameter, and 230V single-phase for smaller fans on distribution transformers. The supply is typically taken from the transformer LV auxiliary supply terminal. Vayuvents supplies both voltage ratings and can provide starter panels if required.
Yes. Vayuvents supplies transformer cooling fans to state DISCOMs and PGCIL substation projects directly and through EPC contractors. We can supply as per transformer OEM specifications and match the frame dimensions for any major Indian or international transformer manufacturer's radiator system.
Contact Vayuvents at enquiry@vayuvents.com or call +91 90961 88703. Share the transformer MVA rating, voltage ratio, number of fans required, radiator channel dimensions, and supply voltage. We will provide a fan selection and commercial proposal within 24 hours.
