Cooling Fan for Dry-Type Transformers
Cross-flow (tangential) fan units for cast resin and VPI dry-type transformers, used for forced-air cooling (AF) duty and as direct replacements on existing enclosures. Send us the nameplate or the old unit's dimensions — we match airflow, voltage, mounting and connector before quoting.
* Values marked TBD are confirmed per order against factory datasheets. We do not publish unverified numbers — request the model list and dimensional PDF with your inquiry.
What the Fan Actually Does
Understanding the AN / AF rating pair is the whole point of a cooling fan order.
AN = natural air cooling
A dry-type transformer left to itself cools by natural convection. Its nameplate AN rating is the output it can carry continuously without any fan running.
AF = forced air cooling
When fans run, the same machine can carry a higher load. The AF figure is set by the transformer manufacturer, not by the fan supplier — we size the fan to hit that requirement.
Why it matters for spares
A failed fan silently returns the transformer to its AN rating. Under peak load or high ambient temperature, that is when windings overheat and insulation ages fast.
Cross-Flow vs. Axial Fan — Which One Fits Your Enclosure
Most dry-type transformer enclosures use cross-flow units; axial fans appear on some compact and OEM designs. Send a photo if you are unsure.
| Cross-flow (tangential) | Axial | |
|---|---|---|
| Air path | Air is drawn along the full length of the impeller and discharged as a wide, even sheet | Air moves parallel to the shaft in a concentrated column |
| Why it suits transformers | Evenly washes the whole winding height — matches the tall, narrow shape of a transformer core | Better for spot cooling or wide open enclosures |
| Typical mounting | Low on the enclosure side or beneath the windings, discharging upward | Panel-mounted on an enclosure wall or roof |
| Replacement note | Length and fixing centres matter more than diameter | Diameter, depth and blade pitch matter most |
| Our availability | TBD* | TBD* |
* Product ranges and available sizes are confirmed per order against factory datasheets.
Specification Checklist — What to Send With Your Inquiry
The more of this table you can fill in, the faster and more accurate your quotation. A nameplate photo plus three dimensions is usually enough for a replacement unit.
| Parameter | What we need from you | Our supply range |
|---|---|---|
| Model / part number | From the old unit's label, or the transformer maker's part list | TBD* |
| Overall length & impeller diameter | Measured in mm on the old unit | TBD* |
| Fixing centres & mounting bracket | Photo plus hole spacing | TBD* |
| Supply voltage | e.g. 230 V single-phase or 400 V three-phase | TBD* |
| Frequency | 50 Hz or 60 Hz (60 Hz matters for many Middle East and Philippine sites) | TBD* |
| Required airflow | m³/h or CFM from your transformer's rating table | TBD* |
| Sound pressure limit | dB(A) at 1 m, if the site has a noise restriction | TBD* |
| Ambient temperature | Especially for Gulf sites with 50 °C+ peaks | TBD* |
| Ingress protection | Required IP rating for indoor / outdoor / coastal | TBD* |
| Thermal protection | PTC thermistor or thermal switch embedded in the motor | TBD* |
| Connection | Terminal box, flying lead, or plug — and required cable length | TBD* |
| Quantity & destination | Units needed, port or door address, preferred Incoterm | TBD* |
* Unverified values are intentionally left blank. We complete this table with factory-confirmed data per inquiry. See also our full transformer accessory range.
Replacement & Retrofit: How It Usually Goes
Photograph the old unit
Two photos — the label and the whole fan from the side — plus the overall length. That is enough for us to start matching.
Confirm the electricals
Voltage, phase and frequency at site. 60 Hz and 400 V three-phase are the two details most often missed on replacement orders.
Check the control side
Most fans are switched by the winding temperature controller, not run continuously. If the old fan failed, confirm the controller and its sensor are still healthy before re-ordering.
Order one spare
Fans are wearing parts. Most maintenance teams stock at least one spare per transformer bank — we can consolidate it with other accessories in the same shipment.
Match the mounting
Bracket geometry varies more than performance does. We confirm fixing centres before production so the unit drops in without modification.
Consolidate the shipment
Add breathers, gauges, valves or gas relays to the same order and pay freight once. See substation spare parts consolidation.
Frequently Asked
Can you match a fan from an existing transformer brand?
Yes — send the nameplate, dimensions and voltage. Cross-flow units are matched primarily on length, impeller diameter, airflow and fixing centres. Availability for your specific size is TBD* until checked against the current model list.
Do you supply 60 Hz versions?
Frequency is one of the fields we confirm per order. Tell us the site frequency and we quote accordingly — availability per model is TBD*.
Can the fan run continuously?
That depends on the motor design and the transformer maker's instructions. Many installations switch fans from the winding temperature controller rather than running them continuously. Motor duty rating for our units is TBD*.
Do you also supply the temperature controller?
Tell us which controller and sensor type you use. Whether we can bundle it with the fans is TBD* — ask with your inquiry.
What documents come with the shipment?
Packing list, commercial invoice and inspection records as standard. Certificates and test reports from the manufacturing partner are available on request; exact document set is TBD* per order.
Replacing a dry-type transformer fan?
Send a photo, the voltage and the quantity — matched offer within 24 hours.