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Specialist Materials for Industry and Science

High Performance

High Performance

MIDEL 7131 is a robust, high performance dielectric fluid that delivers long term stability, even when exposed to extreme variations in temperature and high overloads.

In addition, its excellent moisture tolerance and oxygen stability give MIDEL 7131 a considerable advantage over other transformer fluid options such as mineral oil and natural esters.

Dealing with high temperatures

One of the primary benefits of using MIDEL 7131 is its ability to operate reliably at high temperatures over a sustained period of time. This in turn allows for more compact transformer designs, and has enabled many customers to make considerable space savings that satisfy both design and budget constraints.

These space saving possibilities have been exploited by CG Power in their Midel-filled Bio-SliM® transformers, which are up to 30% smaller and lighter than conventional units with the same power ratings.

There are numerous advantages to be gained from this, as transformers can be installed in restricted spaces (e.g. tower, nacelle) and are easier to transport, handle and remove.

There are many other applications where these properties are particularly useful, for example in wind energy, traction and marine propulsion.

Further high performance properties of MIDEL 7131

As a high performance transformer oil, MIDEL 7131 has many qualities that set it apart from the alternatives. As well as its capabilities at high temperatures, there are plenty more reasons to choose our synthetic transformer fluid:

  • Suitable for use in hybrid and aramid insulation designs
  • Very low pour point (-60˚C)
  • Superior oxygen stability when compared with uninhibited mineral oil and natural ester
  • Can be used in both breathing and sealed transformers
  • Greater moisture tolerance than mineral oil, natural ester and silicone liquid
  • Allows for compact transformer design
  • Better lubricant than mineral oil and natural ester
  • Self-healing, unlike cast resin transformers
  • Lower no-load losses than cast resin transformers
  • No corrosive sulphur – ASTM D1275 and IEC 62535
  • No sludge formation, unlike mineral oil

If you would like more information on the high performance properties of MIDEL 7131, you can contact us or visit our documents archive.



  • Apiezon
  • Metrosil
  • Midel
  • Wolfmet

Products of M&I Materials Ltd.