Frequently asked questions

Q: What is a natural ester?  What is a synthetic ester?

A: From IEEE Standard C57.12.80-2010 IEEE Standard Terminology for Power and Distribution Transformers.

3.268 natural ester fluid: A specially refined and formulated seed-oil (vegetable oil) based dielectric fluid for insulating and cooling electrical equipment for indoor and outdoor installations, which generally conforms to ASTM D6871 when new.

3.438 synthetic ester insulating fluid: A specially formulated polyol ester based less-flammable insulating fluid and coolant for use in fire-resistant indoor and outdoor transformers.


Q: How do natural esters differ from mineral oil?

A:  First, natural esters are vegetable-based.  They have twice the flash and fire point as mineral oil so it is less likely to start on fire.  In fact, there has not been a reported fire-related failure an FR3 fluid-filled transformer since the product was launched.  In addition, the fluid is self-extinguishing so there is no chance of a pool fire.

Second, it has a better environmental footprint as it is readily biodegradable, carbon neutral* and non-toxic and non-hazardous in soil and water. (*according to BEES 4.0 Lifecycle analysis).

Third, its ability to absorb water helps slow the aging process in insulation paper thus protecting the insulation system and extending the asset life of the transformer.

Fourth, with the standardized high temperature capability, transformers filled with FR3 fluid can operate 20C warmer than mineral oil filled transformers without accelerating the aging rate of the solid insulation system.  This capability provides utilities with the flexibility to increase overload capacity up to 20%, extend asset life or a combination.


Q:  Do esters work in both power and distribution transformers?

A:  Yes.  There is a proven track record of distribution and power transformer installations through 420kV.


Q:  Does FR3™ natural ester fluid and Envirotemp™ 200 synthetic esters comply with industry standards?

A:  Yes, both FR3 natural ester fluid and Envirotemp 200 synthetic ester fluid comply with IEEE and IEC standards.


Q:  When did Cargill purchase the dielectric fluid business from Eaton’s Cooper Power Systems?

A:  Cargill collaboratively developed the FR3 fluid product with Eaton’s Cooper Power Systems for the past decade.  In July 2012, Cargill purchased the Envirotemp dielectric fluid business which included FR3 natural ester fluid.


Q:  Do you sell FR3 fluid to other transformer manufacturers?

A:  Yes.  We take a collaborative approach in working with transformer manufacturers and their utility customers to develop the right transformer solution for their particular needs.


Q:  Who do I call if I have questions?

A:  Please start with our customer service team at 1-800-842-3631 or contact the appropriate region below:

North America
+1 800 842-3631

+603 2246-3111

+55 11 5099-3551

+86 21-3332-7107

+31 20 500-6695

+ 91 124 409-0489

+90 216 554 19 27