KNAN (Ester Natural Air Natural) — Transformer Glossary

Cooling method using natural or synthetic ester fluid instead of mineral oil, with natural convection cooling. The 'K' designates ester fluid per IEC naming conventions.

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KNAN (Ester Natural Air Natural)

Cooling method using natural or synthetic ester fluid instead of mineral oil, with natural convection cooling. The 'K' designates ester fluid per IEC naming conventions.

Ester fluid provides significant advantages: fire point of 360°C (vs 170°C for mineral oil), fully biodegradable, and actively absorbs moisture from cellulose insulation — extending paper life by 5–8×. KNAN transformers are ideal for indoor, urban, and environmentally sensitive installations. The higher viscosity of ester fluid requires slightly larger cooling surfaces compared to mineral oil designs. ETS offers both natural ester (plant-based, e.g., FR3™) and synthetic ester (e.g., MIDEL 7131) options.

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ONAF (Oil Natural Air Forced)Cooling method where oil circulates by natural convection but fans force air over the radiators, increasing cooling capacity by 25–40%.

Ester Insulation FluidBiodegradable insulation fluid with superior fire safety properties, available as natural ester (plant-based) or synthetic ester.