Three-phase isolation transformer 400 V / 690 V + N
Step-up to industrial 690 V · vector group Dyn11 · 1 to 100 kVA · made in France
No reviews of this model yet25 kVA20.9 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 a 3 × 400 V supply up to 3 × 690 V, with the neutral brought out: 690 V between phases, 398 V between phase and neutral. It supplies motors, pumps, variable speed drives and industrial equipment designed for 690 V on a site with 400 V distribution, or serves as a 690 V source for a test bench. 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).
Cables, circuit breakers, isolators and terminals on the 690 V feeder must be rated for this voltage: check their rated operational voltage.
Dielectric tests from the datasheet: 5,000 V · 60 s between secondary and frame, 5,500 V · 60 s between primary and secondary.
To step a 690 V supply down to 400 V, choose the 690 V → 400 V + N model, designed for that direction.
When should you use a 400 V / 690 V three-phase isolation transformer?
- Supplying a high-power 690 V motor or pump on a site with 400 V distribution.
- Building a test or acceptance bench for 690 V motors, drives and converters.
- Workshop testing of wind turbine equipment, which often runs at 690 V.
- Supplying construction, quarrying or tunnelling plant and equipment designed for 690 V.
It works at 50 Hz, or at 60 Hz on confirmation. It is not suitable for 400 Hz supplies.
Specifications of the 400 V / 690 V + N three-phase isolation transformer
Values for the selected configuration: 25 kVA · IP23.
- Phase-to-phase voltage
- 3 × 400 V
- Connection
- Delta (Δ)
- Rated line current
- 36.1 A
- Terminals
- 1U 1V 1W + PE
- Phase-to-phase voltage
- 3 × 690 V
- Connection
- Star with neutral (YN)
- Rated line current
- 20.9 A
- Phase-to-neutral voltage
- 398 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 / 0.8 A | D 2 A | 13 / 54 W | 93.8 % | 13 kg | 340 × 310 × 350 | €381.58 | 3 days |
| 2 kVA | 2.9 / 1.7 A | D 4 A | 22 / 107 W | 94.0 % | 20 kg | 340 × 310 × 350 | €430.75 | 3 days |
| 2.5 kVA | 3.6 / 2.1 A | D 4 A | 24 / 122 W | 94.5 % | 22 kg | 340 × 310 × 350 | €448.25 | 3 days |
| 3.15 kVA | 4.5 / 2.6 A | D 6 A | 30 / 135 W | 95.0 % | 26 kg | 340 × 310 × 350 | €467.42 | 3 days |
| 4 kVA | 5.8 / 3.3 A | D 10 A | 42 / 238 W | 93.5 % | 40 kg | 460 × 320 × 500 | €665.75 | 3 days |
| 5 kVA | 7.2 / 4.2 A | D 10 A | 51 / 252 W | 94.3 % | 46 kg | 460 × 320 × 500 | €694.92 | 3 days |
| 6.3 kVA | 9.1 / 5.3 A | D 10 A | 59 / 287 W | 94.8 % | 52 kg | 460 × 320 × 500 | €736.58 | 3 days |
| 8 kVA | 11.5 / 6.7 A | D 16 A | 90 / 284 W | 95.5 % | 74 kg | 525 × 335 × 550 | €1,031.58 | 3 days |
| 10 kVA | 14.4 / 8.4 A | D 16 A | 98 / 335 W | 95.9 % | 81 kg | 525 × 335 × 550 | €1,094.92 | 3 days |
| 12 kVA | 17.3 / 10.0 A | D 20 A | 114 / 370 W | 96.1 % | 91 kg | 525 × 335 × 550 | €1,425.75 | 3 days |
| 16 kVA | 23.1 / 13.4 A | D 25 A | 131 / 424 W | 96.6 % | 105 kg | 525 × 335 × 550 | €1,432.42 | 3 days |
| 20 kVA | 28.9 / 16.7 A | D 32 A | 147 / 484 W | 96.9 % | 117 kg | 525 × 335 × 550 | €1,514.92 | 3 days |
| 25 kVA | 36.1 / 20.9 A | D 40 A | 155 / 579 W | 97.1 % | 126 kg | 525 × 335 × 550 | €1,686.58 | 3 days |
| 30 kVA | 43.3 / 25.1 A | D 50 A | 179 / 672 W | 97.2 % | 142 kg | 525 × 335 × 550 | €1,854.08 | 3 days |
| 40 kVA | 57.7 / 33.5 A | D 63 A | 158 / 829 W | 97.6 % | 139 kg | 700 × 480 × 720 | €2,255.75 | 3 days |
| 50 kVA | 72.2 / 41.8 A | D 80 A | 190 / 980 W | 97.7 % | 162 kg | 700 × 480 × 720 | €2,383.25 | 3 days |
| 63 kVA | 90.9 / 52.7 A | D 100 A | —* | —* | 220 kg | 700 × 480 × 720 | €3,789.92 | 6 days |
| 80 kVA | 115.5 / 66.9 A | D 125 A | —* | —* | 300 kg | 700 × 480 × 720 | €4,591.58 | 6 days |
| 100 kVA | 144.3 / 83.7 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 690 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 × 690 V × A ÷ 1,000 (current on the 690 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 / 690 V + N three-phase isolation transformer.
Why use 690 V?
For the same power, the current at 690 V is 1.7 times lower than at 400 V: smaller cables, lower losses. It is the voltage of large motors, high-power drives and wind power; a 400 V to 690 V transformer creates it from the site supply.
What protection is needed on the 690 V side?
Devices rated for 690 V, sized on the secondary current (“Prim. / sec. current” column in the table). The final choice rests with the installer.
Can I use it to go from 690 V to 400 V?
No: use the 690 V → 400 V + N three-phase isolation transformer instead: its windings, vector group and neutral are designed for that direction.
How do I wire a 400 V / 690 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 400 V / 690 V three-phase isolation transformer, multiply the current per phase on the 690 V side by 690 V and by √3, then take the next standard rating up. For 20 A per phase: 23.9 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 400 V / 690 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 (400 V) of your 400 V / 690 V three-phase isolation transformer, a type D circuit breaker or aM fuses sized for the rated current: for 25 kVA, 36.1 A per phase, i.e. a 40 A type D circuit breaker or 40 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.