Accessories for smart transformers - eDevices

Self-dehydrating breathers

Moisture is a leading cause of transformer aging and outages. By choosing our self-dehydrating breather type eSDB for your transformer, you do not need to worry about site inspections and silica gel replacement. Your transformer will be continuously secured from moisture intake and you can collect data online required for your transformer health management remotely.

The breather is equipped with a digital interface for easy connection to smart grid applications and can be integrated into a system through a central control unit.

It is compatible with our complete eDevice family and can be connected also with third-party devices.

Contact us and get support with the product selection.

Why buy

  • Automatic silica gel regeneration increases transformer performance and safety, assuring no moisture enters the tank during its operation
  • Self-dehydrating breathers do not require regular silica gel replacement on site, this significantly reduces maintenance activities and saves operational costs to the end-user
  • Continuous online monitoring enables the end-users to adopt condition-based maintenance approach and driving asset health management remotely
  • Our self-dehydrating breathers can complement already installed smart accessories, enabling the end-user to adopt gradual digitalization of the transformer based on the individual needs


  • Smart grid applications
  • Available as condition based or time-based technology
  • Suitable for new installations and retrofits
  • Data monitoring available through Modbus and 4-20 mA
  • Compatible with EN and DIN standards

Technical data at a glance

MaterialAll external parts are resistant to transformer oils, salt fog and UV rays (1)
Three types of installation environmentIndoorCorrosion class: C4-MediumRAL 7032
OutdoorCorrosion class: C4-MediumRAL 7032
Tropical proofCorrosion class: C5-MediumGeomet coating
Ambient temperatureFrom -40 °C to +80 °C
Degree of protectionIP45 in compliance with EN60529; IP66 for terminal box
Vibration dampingStandard anti-vibration support can be anchored to the transformer
Overvoltage protectionStandard anti-vibration support can be anchored to the transformer
DessicantColorless, non-poisonous silicagel;
Cable glands2 M25x1.5
ColorRAL 7032
Functional testStandard
Ventilation valveTo prevent the formation of condensation
Wires4 mm2; AWG 24-10 flexible calbes with or without terminals (screws are used to fasten the ables to the terminal board on the terminal box). For digital/analog output 4×1 mm2 (4×0.00155”2) / 2×1 mm2 (2×0.00155”2) shielded twisted pair cable advised.
Rated voltage Power Supply115 / 230 V ac/dc ±10% 50/60 Hz (max/min supply voltage 90/270 ac/dc)
Current consumptionMax 100 mA (during normal operation)
3.0 A (during regeneration process)
Analog output4-20 mA
Digital outputMODBUS RTU
Data logger

(1) For critical environmental conditions, please contact us(

Selection matrix

Time basedCondition
eSDB type1010C12C14C*153040
Connected to a bigger sizeStand alone
Arc suppression coil (Peterson coil)x
Air-filled cable boxesx
Traction transformersx
Network transformers ≤40 MVAx
Network and generator step-up transformers >40 MVA ≤200 MVAx
Generator and network intertie transformers >200 MVAx
Phase shifting transformers ≤40 MVAx
Phase shifting transformers >40 MVA ≤200 MVAx
Phase shifting transformers >200 MVAx
Shunt reactors ≤40 Mvarx
Shunt reactors >40 Mvar ≤200 Mvarx
Shunt reactors >200 Mvarx
HVDC transformersx
Furnace transformersx
Cavern transformersx
Quantity of transformer oil≤40t≤40t≤40t≤40t>40t ≤80t>40t ≤80t>80t

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