Three-phase isolation transformer 690 V / 400 V + N
From industrial 690 V to 400/230 V · vector group Dyn11 · 1 to 100 kVA · made in France
No reviews of this model yet25 kVA36.1 A per phase on the secondary
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- 5-year warranty · wound and tested in Gailhan
Key features
This three-phase isolation transformer steps an industrial 3 × 690 V supply down to 3 × 400 V + N: 400 V between phases and 230 V between each phase and neutral. It supplies standard equipment and auxiliaries — 400 V machines, control systems, lighting, sockets — on sites with 690 V distribution: wind turbines, mines and quarries, tunnels, heavy industry. 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).
The feeder supplying the transformer (cables, circuit breaker, isolator) must be rated for 690 V: check its rated operational voltage.
Between each phase and the secondary neutral you have 230 V: site lighting, sockets and control systems without another transformer.
Dielectric tests from the datasheet: 5,000 V · 60 s between primary and frame, 5,500 V · 60 s between primary and secondary.
When should you use a 690 V / 400 V three-phase isolation transformer?
- Supplying the auxiliaries of a wind turbine (lighting, sockets, control systems) from its 690 V system.
- Supplying 400/230 V to equipment in mines, quarries or tunnel boring machines with 690 V distribution.
- Connecting standard 400 V machines in a factory with 690 V distribution.
- Supplying a 400 V test bench from a 690 V system.
It works at 50 Hz, or at 60 Hz on confirmation. It is not suitable for 400 Hz supplies.
Specifications of the 690 V / 400 V + N three-phase isolation transformer
Values for the selected configuration: 25 kVA · IP23.
- Phase-to-phase voltage
- 3 × 690 V
- Connection
- Delta (Δ)
- Rated line current
- 20.9 A
- Terminals
- 1U 1V 1W + PE
- Phase-to-phase voltage
- 3 × 400 V
- Connection
- Star with neutral (YN)
- Rated line current
- 36.1 A
- Phase-to-neutral voltage
- 230 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 | 0.8 / 1.4 A | D 2 A | 12 / 59 W | 93.4 % | 12 kg | 340 × 310 × 350 | €381.58 | 3 days |
| 2 kVA | 1.7 / 2.9 A | D 2 A | 22 / 105 W | 94.0 % | 20 kg | 340 × 310 × 350 | €430.75 | 3 days |
| 2.5 kVA | 2.1 / 3.6 A | D 4 A | 24 / 125 W | 94.4 % | 22 kg | 340 × 310 × 350 | €448.25 | 3 days |
| 3.15 kVA | 2.6 / 4.5 A | D 4 A | 30 / 140 W | 94.9 % | 26 kg | 340 × 310 × 350 | €467.42 | 3 days |
| 4 kVA | 3.3 / 5.8 A | D 4 A | 42 / 232 W | 93.6 % | 40 kg | 460 × 320 × 500 | €665.75 | 3 days |
| 5 kVA | 4.2 / 7.2 A | D 6 A | 51 / 264 W | 94.1 % | 46 kg | 460 × 320 × 500 | €694.92 | 3 days |
| 6.3 kVA | 5.3 / 9.1 A | D 6 A | 59 / 289 W | 94.8 % | 52 kg | 460 × 320 × 500 | €736.58 | 3 days |
| 8 kVA | 6.7 / 11.5 A | D 10 A | 90 / 277 W | 95.6 % | 74 kg | 525 × 335 × 550 | €1,031.58 | 3 days |
| 10 kVA | 8.4 / 14.4 A | D 10 A | 98 / 325 W | 95.9 % | 81 kg | 525 × 335 × 550 | €1,094.92 | 3 days |
| 12 kVA | 10.0 / 17.3 A | D 16 A | 114 / 357 W | 96.2 % | 92 kg | 525 × 335 × 550 | €1,425.75 | 3 days |
| 16 kVA | 13.4 / 23.1 A | D 16 A | 131 / 421 W | 96.7 % | 105 kg | 525 × 335 × 550 | €1,432.42 | 3 days |
| 20 kVA | 16.7 / 28.9 A | D 20 A | 147 / 513 W | 96.8 % | 116 kg | 525 × 335 × 550 | €1,514.92 | 3 days |
| 25 kVA | 20.9 / 36.1 A | D 25 A | 163 / 542 W | 97.3 % | 131 kg | 525 × 335 × 550 | €1,686.58 | 3 days |
| 30 kVA | 25.1 / 43.3 A | D 32 A | 179 / 663 W | 97.3 % | 142 kg | 525 × 335 × 550 | €1,854.08 | 3 days |
| 40 kVA | 33.5 / 57.7 A | D 40 A | 150 / 867 W | 97.5 % | 132 kg | 700 × 480 × 720 | €2,255.75 | 3 days |
| 50 kVA | 41.8 / 72.2 A | D 50 A | 206 / 866 W | 97.9 % | 173 kg | 700 × 480 × 720 | €2,383.25 | 3 days |
| 63 kVA | 52.7 / 90.9 A | D 63 A | —* | —* | 220 kg | 700 × 480 × 720 | €3,789.92 | 6 days |
| 80 kVA | 66.9 / 115.5 A | D 80 A | —* | —* | 300 kg | 700 × 480 × 720 | €4,591.58 | 6 days |
| 100 kVA | 83.7 / 144.3 A | D 100 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 690 V / secondary at 400 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 × 400 V × A ÷ 1,000 (current on the 400 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 690 V / 400 V + N three-phase isolation transformer.
How does it differ from a 400 V / 690 V transformer?
The direction: this three-phase isolation transformer steps a 690 V supply down to 400 V + N. To supply 690 V equipment from a 400 V supply, choose the 400 V → 690 V + N model.
Does the secondary provide 230 V?
Yes: the 690 V to 400 V transformer provides 230 V between each phase and neutral, and 400 V between phases. Connected to earth, the neutral gives a TN-S system.
How do I wire a 690 V / 400 V three-phase isolation 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 690 V / 400 V three-phase isolation transformer, multiply the current per phase on the 400 V side by 400 V and by √3, then take the next standard rating up. For 32 A per phase: 22.2 kVA, so a 25 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 690 V / 400 V three-phase isolation 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 (690 V) of your 690 V / 400 V three-phase isolation transformer, a type D circuit breaker or aM fuses rated for 690 V, sized for the rated current: for 25 kVA, 20.9 A per phase, i.e. a 25 A type D circuit breaker or 25 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.