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FR3® natural ester dielectric fluid: Leading the way

Benefitting utilities and businesses, to better protect and serve communities.

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From its very first validation tests over 25 years ago to the latest installations of FR3-fluid-filled power and distribution transformers across the globe, FR3 natural ester dielectric fluid has led the industry. FR3 fluid enables more cost-effective, more resilient, higher-performing, safer, and environmentally better ways to power how communities live, play, work, and thrive.

Although mineral oil has long been the fallback transformer oil, it simply isn’t the optimal dielectric fluid. In millions of installations worldwide, FR3 natural ester dielectric fluid has proven to be superior in the ways you value the most. We have the leadership, experience, and proof, so you can be sure to take advantage of FR3 fluid’s benefits.

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Why FR3 Fluid

FR3 fluid outperforms mineral oil in overall cost savings, grid resiliency, transformer performance, fire safety, and environmental benefits. See why these critical reasons to switch from mineral oil to FR3 natural ester transformer oil matter. Learn more or Download Brochure.

Grid resiliency that pays in more ways than one

A transformer’s solid insulation system and its dielectric fluid constrain its (temperature) operating limits. Because of FR3 fluid’s properties, transformers containing this natural ester can operate up to 20°C warmer than can mineral-oil-filled equivalents—enabling increased loading capability by up to 20% (or even more in some cases). When a transformer is designed to use FR3 fluid, this increased capacity may be even higher. Not only can FR3 fluid help you respond to fluctuating power demand, it won’t accelerate asset aging and may extend transformer life.

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Average total cost of ownership savings



20 percent

Up to 20% more load capacity than mineral oil




Up to 8X longer insulation life



Mineral oil's flash and fire points



Reported fires


Installations worldwide


FR3 Fluid Applications

Power Transmission and Distribution

FR3 fluid is successfully used in power generation and distribution transformers of all voltage classes. When compared to mineral oil, FR3 fluid delivers utilities superior performance and measurable cost efficiencies.

When you choose FR3 fluid for your utility, you empower a flexible and resilient grid to benefit your business, community, and the planet.



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Solar Power

FR3 fluid is used in land-based and floating solar plants across the globe. 

Solar farm transformers with FR3 fluid enjoy major performance benefits like higher flexible loading capacity and minimal maintenance. The environmental benefits allow for smaller installation footprints and improved fire safety over mineral oil. 


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Wind Power

Demand for wind power continues to expand and wind turbines for large-scale wind farms have grown more powerful. Now, it is essential to specify high-performing transformers that are compact, lightweight and low maintenance.

Using FR3 fluid in wind turbine transformers— for both onshore and offshore applications—easily meet these criteria with a notable impact on the bottom line.


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FR3-fluid-filled transformers can extend the paper insulation life up to 8X longer than mineral-oil-filled equivalents because of its superior moisture handling capabilities. You also get improved fire safety with a fire point more the 2X higher than mineral oil. As a result, when you retrofill any mineral-oil-filled transformer with FR3 fluid, you extend asset life while also lowering the risk of fire.


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FR3 fluid has been tested and proven by numerous internal tests, third-party research organizations and universities, and customers many times over, and for decades. See why its superiority to mineral oil is beyond question.


Technical Details

Higher flash and fire points (compared to mineral oil). Dielectric strength even at very cold temperatures. Chemical interactions that extend the life of a transformer’s solid insulation. Ultimately and readily biodegradable. See FR3 fluid’s technical details.


In the News

Browse the latest Cargill power systems news and headlines from around the globe. Catch up on recently published case studies and articles including our industry experts to learn best practices and how FR3® fluid is being used in the field.


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