Accessories for smart transformers - eDevices
Liquid level indicators for smart transformers
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 liquid level indicator type eOLI, an evolution of our conventional liquid level indicators, and continuously monitor from the remote any unexpected or accidental oil leakages that may lead to a transformer failure. The operator can monitor the preset values remotely or 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 and can be connected also with third party devices.
Contact us and get support with the product selection.

Why buy
- Continuous online monitoring at any time and from the remote
- Proven technology enabling the end-user informed decision making about effective transformer maintenance schedule
- 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
Application
- Smart grid applications
- Liquid-filled transformers with or without conservator
- Conservator with rubber bag
- Suitable for new installations and retrofits
- Suitable for offshore environment
- Suitable for tropical climates
Additional accessories
- eViewer enabling accurate liquid level reading at men-height on-site

Technical data at a glance
Housing | Aluminum alloy | |
Installation | Indoor, outdoor and Tropical proof | |
Lens | Plycarbonate or tempered glass | |
Flange | Aluminum alloy | |
Flange design | eOLI22 COMEM design, 8 holes | eOLI Compatible with all transformer designs |
Dial | Numbers and letters directly printed on the aluminum plate Customizable range (MIN +20°C MAX, other available) Red needle | |
Adjustable switches | Yes | |
Ventilation valve | Yes | |
Float element | Expanded ebonite | |
Float movement | Radial, axial, axial for rubber bag | |
Oil temperature | From -40°C up to +120°C | |
Ambient temperature | From -40°C to +80°C | |
Cable gland | 3; M25x1.5 | |
Degree of protection | IP66 | |
Power supply | 24 V dc ±10% polarized | |
Analog output | 4-20mA | |
Digital output | Modbus RTU Data logger | |
eViewer – additional dial at men height | Enables liquid level value check on site; Power supply 24 V dc |