The Sigma 702ET Transformer Oil Analyzer has been specifically designed to guide the user through the measurement of interfacial tension of transformer oil according to relevant standards.

Features & Benefits

  • Designed for oil-water interfacial tension measurements in accordance to the ASTM D971 and IEC 62961 standards.
  • Guides the user throughout the measurement process in compliance with the standards.
  • High-end accuracy with precision microbalance and mechanics.
  • Stand-alone functionality without the need for an external computer. Results can be exported to PC or printed our directly with an optional printer.


  • Quality control of transformer oil (IEC 62961 and ASTM D971)

Product details

The open design and convenient control keyboard operations makes the Sigma 702ET extremely easy to use. Results are displayed on a large integrated digital screen. The instrument comes with data collection software and can be connected to an external computer for additional data storage and simple reporting.

Sigma 702ET is specifically designed for oil-water interfacial tension (IFT) measurements. The instrument is particularly suitable for IFT determinations of transformer oils and hydrocarbon fuels in accordance with IEC 62961, ASTM D971 and IEC 60422 standards and comes with software designed for oil-water measurements. 

Sigma 702ET is typically used in the energy industry to check the interfacial tension between transformer oils and water.

Technical specifications

For a comparison chart, see:

Application examples

Application note ASTM D-971 Standard

IEC 62961 and ASTM D971 standard test method for interfacial tension of oil against water by the ring method

The IEC 62961 and ASTM D971 standard is used to determine the possible contaminants of hydrocarbon fluids. The purity of hydrocarbon fluids is important in many industrial areas, such as in aviation, diesel fuels and transformer oils.

It is well known that oil-water interfacial tension correlates with the purity and functionality of oils that are used in transformers for cooling, insulation and protection against arcing. Electrical stress and contamination may modify the oil performance. Sigma 702ET with a platinum Du Noüy ring can be used to control the oil quality according to IEC 62961 and ASTM D971-12 standards.


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