ET3S / ET3o / ET1o — LV separating, isolating and safety transformers
Country: Poland · Model: ET3S / ET3o / ET1o
Single- and three-phase ET3S, ET3o and ET1o transformers galvanically separate circuits up to 1000 V at ratings from 0.05 to 100 kVA. They are installed in control cabinets and on lighting, signalling and sensitive-equipment circuits, and the safety versions power the equipment of repair crews on ships and in mines.
- Types
- separating (ET3S, Dyn5), isolating with screen / split bobbin (ET3o), safety (ET1o, ET3o, U2 < 50 V)
- Power
- separating three-phase 0.05–10 kVA (per photo captions); isolating ET3o 0.05–40 kVA; safety — single-phase up to 100 kVA, three-phase up to 40 kVA
- Voltage
- up to 1000 V
- Insulation class
- B up to 5 kVA, F above 5 kVA
Technical specifications
| Types | separating (ET3S, Dyn5), isolating with screen / split bobbin (ET3o), safety (ET1o, ET3o, U2 < 50 V) |
|---|---|
| Power | separating three-phase 0.05–10 kVA (per photo captions); isolating ET3o 0.05–40 kVA; safety — single-phase up to 100 kVA, three-phase up to 40 kVA |
| Voltage | up to 1000 V |
| Insulation class | B up to 5 kVA, F above 5 kVA |
| Protection degree | IP00; enclosures IP23/IP44/IP54 |
| Standards | EN/IEC 61558-2-1, -2-4, -2-6; EN/IEC 60726 |
Replacement for
TSZI, TSZ 0.38/0.23 kV (dry low-voltage), OSM1-0.063…4 kVA (single-phase), OSO; YaTP-0.25 (safety step-down)
selected by purpose and main parameters, please confirm with the manager
Replacement pages: ОСМ1-0,063, ОСМ1, ЯТП-0,25, ЯТП
Specifications are taken from the manufacturer’s technical documentation. Updated .
Description
In the ET3S separating transformers the windings are separated by basic insulation without a split bobbin or screen, vector group Dyn5, built to EN/IEC 61558-2-1 and EN/IEC 60726. In the ET3o isolating transformers a split bobbin or an electrostatic screen sits between the windings, so mains noise passes into the secondary circuit much more weakly. Safety transformers give extra-low voltage below 50 V with protective separation from the mains, which lowers the risk of electric shock. Single-phase safety units up to 10 kVA are made to PN-EN 61558-2-6, isolating ones up to 25 kVA to PN-EN 61558-2-4. Insulation class B is used up to 5 kVA, class F on more powerful units. The climatic version C1/E0 is designed for onshore installations, C2/E1 for marine and mining ones, ambient temperature 40 or 45 °C, frequency 50/60 Hz.
How to choose
The type is chosen by what the circuit must be protected from. For ordinary control circuits the ET3S at 0.05–10 kVA is enough, and when mains noise harms sensitive electronics, take the screened ET3o, three-phase up to 40 kVA. If the secondary voltage must be below 50 V for safety reasons, a safety version is needed, single-phase up to 100 kVA or three-phase up to 40 kVA. Taps, terminal side and mounting on a base welded to the core or on bolt-on angles are agreed for the specific cabinet. For IT networks of operating theatres there are the medical ET1MED / ET3MED at 2.5–10 kVA, for railway signalling and interlocking devices the ET3KOL / ET1KOL.
Request a price and lead time
ET3S / ET3o / ET1o — LV separating, isolating and safety transformers. We reply within one business day.
Or email office@usk.ua or call +38 (044) 339-50-20.
FAQ
How does the ET3o isolating transformer differ from the ET3S separating transformer?
In the ET3o a split bobbin or an electrostatic screen sits between the windings, which further limits noise transfer. In the ET3S the windings are separated by basic insulation only.
What is the maximum power of an extra-low-voltage safety transformer?
Single-phase safety transformers are made up to 100 kVA, three-phase up to 40 kVA, with a secondary voltage below 50 V in both.
What IP protection degree can be ordered for a separating transformer?
The basic unit is open, IP00, and is installed in a cabinet. For standalone mounting it is supplied in an IP23, IP44 or IP54 enclosure with cable glands.
Are these transformers suitable for ships and mines?
Yes, the C2/E1 climatic version exists for marine and mining conditions, C1/E0 for onshore installations, ambient temperature 40 or 45 °C.
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Need a price, lead time or replacement?
Send us a request and we will confirm the configuration, lead time and delivery terms. We reply by email.