Dry-type transformer fans
Date: July 19, 2025 08:13:44
Dry-type transformerCooling Fans(referred to as "dry-variable fan") is the role of "forced air cooling" (AF), compared with the natural air-cooled (AN), in a short period of time to increase the transformer capacity of about 50%, and to extend the life of the insulation. The following fan selection - installation - wiring - control - operation and maintenance "a clear, convenient project directly on the ground.
I. Structure and classification
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Cross-flow (GFDD series): single-phase 220 V, length 365-770 mm, impeller diameter 90-155 mm, power 25-90 W, air volume 570-1800 m³/h.
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Top-blowing type: installed on the top of the transformer, the cold air is blown vertically downward, suitable for cabinets with narrow space.
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Side-blowing type: installed on both sides of the lower part of the coil, with a horizontal angle of 135 °, the cold air is blown directly into the air ducts of the high and low voltage coils, the most commonly used.
II. Quick reference table for selection (conventional 50 Hz, 220 V single-phase)
| Transformer capacity (kVA) | Recommended Models | Quantity per unit | Air volume (m³/h) | Power (W) |
|---|---|---|---|---|
| 315-630 | GFDD365-120 | 4-6 | 580 | 40 |
| 800-1600 | GFDD470-120 | 4-6 | 750 | 60 |
| 1600-2500 | GFDD590-120 | 6 | 950 | 60 |
| 2500-3150 | GFDD690-120 | 6 | 1050 | 60 |
| 3150-5000 | GFDD770-150 | 6 | 1800 | 90 |
III. Installation points
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Position: either side of the clip under the coil, or top, with the air outlet aligned with the coil air duct.
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Angle: Side-blown blades approximately 135° from horizontal, top-blown vertically downward.
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Fixing: foot support + rubber damping pads to ensure no resonance; air inlet ≥20 cm from obstacles.
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Wiring: fan power line and thermostat fan terminals (normally open contact 10 A/250 VAC) are directly connected in series; the fan automatically stops after the thermostat is powered down, meeting the requirements of fire linkage.
IV. Control Logic (LD-B10 series as an example)
- Start: Winding temperature ≥ "Ob(set) + dF(return difference)".
- Stop: Winding temperature ≤ "Ob - dF".
- Timed self-check: automatic start/stop for 2 min every 24 h to prevent bearing stalling (can be turned off).
- Manual: "Manual/Auto" key on the panel switches; manual start requires the temperature to drop below the return difference before automatic reset.
- Start: Winding temperature ≥ "Ob(set) + dF(return difference)".
- Stop: Winding temperature ≤ "Ob - dF".
- Timed self-check: automatic start/stop for 2 min every 24 h to prevent bearing stalling (can be turned off).
- Manual: "Manual/Auto" key on the panel switches; manual start requires the temperature to drop below the return difference before automatic reset.
V. Typical Wiring Diagram
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Power supply: L → thermostat fan terminal 11 → fan L; N → fan N.
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Standby: Fire cut relay normally closed contacts are strung into the fan power supply to force the fan to stop in case of fire.
VI. Operation and maintenance
- Monthly: Clean ash, check for blade deformation, loose fasteners.
- Every six months: measured vibration ≤ 4.5 mm/s; noise ≤ 55 dB(A).
- Annually: Measure insulation resistance ≥ 2 MΩ; thermostat fan output contacts on and off test.
- Monthly: Clean ash, check for blade deformation, loose fasteners.
- Every six months: measured vibration ≤ 4.5 mm/s; noise ≤ 55 dB(A).
- Annually: Measure insulation resistance ≥ 2 MΩ; thermostat fan output contacts on and off test.
in a word
"For dry transformers with a capacity of ≤ 1600 kVA, 4-6 sets of GFDD470-120 cross-flow fans are routinely installed, which can be started and stopped automatically by a thermostat; for larger capacities or high ambient temperatures, the fans can be connected in parallel with a redundant fan or changed to a top-blowing type, and the design of the ventilation ducts can be strengthened."
"For dry transformers with a capacity of ≤ 1600 kVA, 4-6 sets of GFDD470-120 cross-flow fans are routinely installed, which can be started and stopped automatically by a thermostat; for larger capacities or high ambient temperatures, the fans can be connected in parallel with a redundant fan or changed to a top-blowing type, and the design of the ventilation ducts can be strengthened."
