Accessories for smart transformers - eDevices

Contactless liquid level indicators

Liquids like mineral and silicone oils insulate and cool a transformer. You need to monitor the level of the oil to assure reliable and safe operation of the transformer.

Choose our new contactless ultrasonic sensor-based liquid level indicator type CU eOLI and get continuous high accuracy measurement of liquid level in transformer with or without rubber bag. The sensor calculates the distance of the targeted surface in the transformer measuring the ultrasonic wave flight time.

The monitors the preset values remotely or choose to visualize the values on-site at men-height through the easy-to-read eViewer dial installed on the transformer wall and decide on the best transformer maintenance schedule.

The indicator 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, can be connected also to third-party devices, and be part of our modular monitoring ecosystem for transformer diagnostics – MeDICA.

Contact us and get support with the product selection.

Why buy

  • Continuous online monitoring enables the end-users to adopt condition-based maintenance approach and driving asset health management remotely
  • High accuracy measurement of liquid level values enabling the end-user informed decision making about effective transformer maintenance schedule
  • No moving parts are immersed in the oil, minimizing any possible risk caused by mechanical materials inside the conservator
  • Customizable mounting flange suitable for all transformer designs
  • Adjustable value settings for alarms and switches
  • Compatibility with other eDevices, and third-party accessories enables the end-user a controlled and gradual digitalization of the transformer and remote asset health monitoring
  • Easy installation
  • Maintenance free


  • Smart grid applications
  • Liquid-filled transformers with or without rubber bag
  • Transformer conservator
  • Transformer tank
  • Suitable for new installations and retrofits
  • Suitable for offshore environment
  • Suitable for tropical climates
  • Part of our MeDICA solution

Additional accessories

  • eViewer enabling accurate liquid level reading at men-height on-site

Technical data at a glance

Sensor technologyUltrasonic
HousingAluminum alloy
InstallationIndoors, Outdoors, Coastal area, Off shore
FlangeAluminum alloy
Measurement range for CUeOLI100120 – 1,000 mm
Measurement range for CUeOLI200200-2,000 mm
Power supply24 V dc ± 10%
Analog output4-20 mA (MAX Load 450Ω)
Digital outputModbus RTU
Relay1X programmable changeover relay
Accuracy0,5% FS
Repeatability0,5% FS
Power consumption<200mA @ 24 V dc
Operating/storage temperaturefrom -25°C up to +70°C
Temperature auto compensationYes
Degree of protectionIP65
Cable gland2; M25x1,5
Flange designDN65
eViewer – additional dial at men heightEnables liquid level value check on-site; Power supply 24 V dc

Related offering