Three-phase transformer 400 V / 208 V + N (208Y/120 V)
North American 208Y/120 V supply in Europe · vector group Dyn11 · 1 to 100 kVA · made in France
No reviews of this model yet20 kVA55.5 A per phase on the secondary
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- 5-year warranty · wound and tested in Gailhan
Key features
This three-phase transformer recreates the North American 208Y/120 V system in Europe: from your 3 × 400 V three-phase supply, it provides 208 V between phases and 120 V between each phase and neutral. It is the solution for running machines built for the United States or Canada — machine tools, commercial kitchen equipment, air conditioning, UPS systems and IT racks. Vector group Dyn11, electrostatic shield as standard, 1 to 100 kVA in IP00, IP23 or IP54, and 125 to 1,000 kVA on request: it is wound and tested in our workshop in Gailhan (Gard, southern France).
A three-phase transformer changes the voltage, not the frequency. Check the rating plate of your machine to make sure it accepts 50 Hz (marked “50/60 Hz”): a motor designed for 60 Hz runs about 17 % slower at 50 Hz.
Some North American machines are designed for 230–240 V between phases, not 208 V: in that case you need the 400 V → 230 V + N model. The voltage is shown on the rating plate.
Between each phase and the secondary neutral you have 120 V: the voltage of North American sockets and controls.
When should you use a 400 V / 208 V three-phase transformer?
- Machine tools and CNC controls imported from the United States or Canada.
- Commercial kitchens: ovens, fryers and dishwashers designed for 208 V.
- 208 V air conditioning, chillers and compressors, including rooftop units.
- UPS systems, PDUs and IT racks designed for the North American supply.
- Lifts, hoists and drives of North American origin, exhibition or demonstration equipment.
It works at 50 Hz, or at 60 Hz on confirmation. It is not suitable for 400 Hz supplies.
Specifications of the 400 V / 208 V + N three-phase transformer
Values for the selected configuration: 20 kVA · IP23.
- Phase-to-phase voltage
- 3 × 400 V
- Connection
- Delta (Δ)
- Rated line current
- 28.9 A
- Terminals
- 1U 1V 1W + PE
- Phase-to-phase voltage
- 3 × 208 V
- Connection
- Star with neutral (YN)
- Rated line current
- 55.5 A
- Phase-to-neutral voltage
- 120 V
- Terminals
- 2U 2V 2W 2N + PE
- Type
- Dry-type transformer, natural cooling
- Core
- 3 limbs, one coil per phase
- Insulation class
- H (180 °C)
- Electrostatic shield
- Fitted as standard, earthed
- Standards
- EN IEC 61558-1 and EN IEC 61558-2-4
- IP rating
- IP23, ventilated metal enclosure
- Overall dimensions L × W × H
- 525 × 320 × 550 mm
- Weight
- 131 kg
- Mounting
- 2 feet, holes Ø 12 mm
- Ambient temperature
- 40 °C maximum
From 63 to 100 kVA, losses and efficiency are available on request.
Ratings and prices
From 1 to 100 kVA. Above that, on request.
| Rating | Prim. / sec. current | Recommended circuit breaker | No-load / load losses | Efficiency | Weight | Dimensions (mm) | Price ex VAT | Dispatch |
|---|---|---|---|---|---|---|---|---|
| 1 kVA | 1.4 / 2.8 A | D 2 A | 12 / 59 W | 93.4 % | 12 kg | 340 × 310 × 350 | €381.58 | 3 days |
| 2 kVA | 2.9 / 5.6 A | D 4 A | 22 / 107 W | 94.0 % | 20 kg | 340 × 310 × 350 | €430.75 | 3 days |
| 2.5 kVA | 3.6 / 6.9 A | D 4 A | 24 / 126 W | 94.3 % | 22 kg | 340 × 310 × 350 | €448.25 | 3 days |
| 3.15 kVA | 4.5 / 8.7 A | D 6 A | 30 / 136 W | 95.0 % | 26 kg | 340 × 310 × 350 | €467.42 | 3 days |
| 4 kVA | 5.8 / 11.1 A | D 10 A | 42 / 239 W | 93.4 % | 40 kg | 460 × 320 × 500 | €665.75 | 3 days |
| 5 kVA | 7.2 / 13.9 A | D 10 A | 51 / 255 W | 94.2 % | 46 kg | 460 × 320 × 500 | €694.92 | 3 days |
| 6.3 kVA | 9.1 / 17.5 A | D 10 A | 59 / 287 W | 94.8 % | 52 kg | 460 × 320 × 500 | €736.58 | 3 days |
| 8 kVA | 11.5 / 22.2 A | D 16 A | 90 / 284 W | 95.5 % | 74 kg | 525 × 335 × 550 | €1,031.58 | 3 days |
| 10 kVA | 14.4 / 27.8 A | D 16 A | 98 / 332 W | 95.9 % | 81 kg | 525 × 335 × 550 | €1,094.92 | 3 days |
| 12.5 kVA | 18.0 / 34.7 A | D 20 A | —* | —* | 94 kg | 525 × 335 × 550 | €1,118.25 | 3 days |
| 16 kVA | 23.1 / 44.4 A | D 25 A | 131 / 407 W | 96.7 % | 105 kg | 525 × 335 × 550 | €1,432.42 | 3 days |
| 20 kVA | 28.9 / 55.5 A | D 32 A | 147 / 496 W | 96.9 % | 117 kg | 525 × 335 × 550 | €1,514.92 | 3 days |
| 30 kVA | 43.3 / 83.3 A | D 50 A | 179 / 667 W | 97.3 % | 142 kg | 525 × 335 × 550 | €1,854.08 | 3 days |
| 40 kVA | 57.7 / 111.0 A | D 63 A | 166 / 771 W | 97.7 % | 144 kg | 700 × 480 × 720 | €2,255.75 | 3 days |
| 50 kVA | 72.2 / 138.8 A | D 80 A | 190 / 980 W | 97.7 % | 161 kg | 700 × 480 × 720 | €2,383.25 | 3 days |
| 63 kVA | 90.9 / 174.9 A | D 100 A | —* | —* | 220 kg | 700 × 480 × 720 | €3,789.92 | 6 days |
| 80 kVA | 115.5 / 222.1 A | D 125 A | —* | —* | 300 kg | 700 × 480 × 720 | €4,591.58 | 6 days |
| 100 kVA | 144.3 / 277.6 A | MCCB 160 A | —* | —* | 345 kg | 700 × 480 × 720 | €5,358.25 | 6 days |
| 125 to 1,000 kVA | On request, in the standard ratings: 125, 160, 200, 250, 315, 400, 500, 630, 800 and 1,000 kVA. Request a quote | |||||||
Rated currents: primary at 400 V / secondary at 208 V. Type D circuit breaker on the primary. Losses and efficiency: design values at full load. * 63 to 100 kVA: losses and efficiency on request. Prices exclude carriage. Calculator formula: kVA = √3 × 208 V × A ÷ 1,000 (current on the 208 V side), next standard rating up.
Wiring diagram and enclosure drawing
Extracts from the datasheet: coil-by-coil connections and enclosure dimensions.
Installation and protection
Values for 25 kVA. Sizing of the installation remains the installer's responsibility.
Upstream protection
Type D circuit breaker 40 A
or aM fuses 40 A · inrush current ≈ 433 A peak
Secondary neutral
- Earthed: TN-S system, the most common.
- Isolated from earth: IT system, with an insulation monitoring device.
Safety
- Connection by a qualified person.
- Earth connected before switching on.
- IP00: in a cabinet or a closed electrical room.
Standards, warranty and options
A standard transformer, built to order and adaptable to your installation.
Frequently asked questions
About the 400 V / 208 V + N three-phase transformer.
Why 208 V and 120 V?
It is the supply used in North American commercial buildings: 208 V between phases, 120 V between a phase and neutral. This three-phase transformer reproduces it from the European 3 × 400 V supply.
My machine is designed for 60 Hz: is that a problem?
The 400 V to 208 V transformer does not change the frequency: the machine will receive 50 Hz. If its rating plate says “50/60 Hz”, all is well. If not, motors run about 17 % slower and may overheat: ask the machine manufacturer for advice.
208 V or 230/240 V: which should I choose?
Whichever is on the machine rating plate. 208 V: this transformer. 230 or 240 V between phases: the 400 V → 230 V + N model.
How do I wire a 400 V / 208 V three-phase transformer?
Primary connection: the supply goes to terminals 1U, 1V and 1W, earth to PE; the delta connection is made at the factory. On the secondary, the outgoing circuits leave from terminals 2U, 2V and 2W, and the neutral from terminal 2N. The full wiring diagram is on the datasheet.
Which rating should I choose?
To choose your 400 V / 208 V three-phase transformer, multiply the current per phase on the 208 V side by 208 V and by √3, then take the next standard rating up. For 40 A per phase: 14.4 kVA, so a 16 kVA unit. The calculator above the table does this for you.
Do you make three-phase transformers above 100 kVA?
Yes, on request: we also make this 400 V / 208 V three-phase transformer from 125 to 1,000 kVA, in the standard ratings 125, 160, 200, 250, 315, 400, 500, 630, 800 and 1,000 kVA. Choose the rating at the top of the page, below the priced ratings, or request a quote: reply within 48 h.
What upstream protection should I install?
On the primary (400 V) of your 400 V / 208 V three-phase transformer, a type D circuit breaker or aM fuses sized for the rated current: for 20 kVA, 28.9 A per phase, i.e. a 32 A type D circuit breaker or 32 A aM fuses. At switch-on, the inrush current reaches about twelve times the rated current; the rating for each size is given in the table.
IP00, IP23 or IP54: which should I choose?
IP00: open-frame transformer, to be installed in a cabinet or a closed electrical room. IP23: ventilated enclosure, for a plant room sheltered from water. IP54: closed enclosure, protected against dust and splashing water.
What are the lead times?
From 1 to 50 kVA, dispatched from our workshop within 3 working days; from 63 to 100 kVA, within 6 working days. Up to 30 kg, the transformer ships as a parcel, with free delivery within France. Heavier units travel on a pallet with Kuehne + Nagel: 48 to 72 hours in mainland France, 96 hours elsewhere in Europe; pallet delivery is free from €1,000 ex VAT, otherwise a flat €50 ex VAT.
Customer reviews
No reviews of this model yet. Here is what customers say about another three-phase transformer built the same way (reviews in French).
Livraison rapide, produit conforme et bien emballé. Installation sans difficulté, parfait pour créer un neutre. Le service téléphonique est top, fabrication française en plus. Je recommande sans hésiter.
Produit reçu rapidement, très bien emballé. Fonctionne parfaitement sur notre installation industrielle. Fabrication sérieuse, rien à signaler après plusieurs semaines d'utilisation. Content d'acheter français.
Produit conforme à la description, fabrication robuste et délai respecté. Service client à l’écoute, installation réalisée sans souci. Très satisfait de la qualité, matériel professionnel, rien à dire de plus.
Other three-phase transformers
Built the same way, for other voltages.