Top Of The Class – The K-Class Transformer Fluid

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Top Of The Class The K-Class Transformer Fluid
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• KNAN, KNAF, ONAN, ONAF what do they mean?
  Heres how to unlock the cooling class code for
  liquid filled transformers.
• The ANSI/IEE Standard C57.12.00 defines a 4
  character code to describe the cooling attributes
  of the transformer. The first letter refers to
  the main cooling medium (i.e. in contact with the
  windings). Decode as follows

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• O mineral or synthetic oil with a flash point
  less than 300 degrees
• K insulating fluid with a flash point greater
  than 300 degrees (K-class fluid)
• The second letter designates the circulation
  mechanism for the main cooling medium. It may
  be
• F forced
• N natural
• D forced through a cooler

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• The third letter refers to the external cooling
  media, which can only be one of two options
• A air
• W water
• Leaving the fourth letter to designate how the
  external cooling media operates. It can be
• F forced (e.g. fans or pumps)
• N natural (convection)

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• Thus by way of example KNAF designates a
  non-mineral oil filled unit (likely a synthetic
  ester) that has natural convection flow in the
  tank and utilizes fan cooling externally.
• Of special interest to Benzoil is the first
  letter, O or K. Benzoil supplies standard
  mineral oils (the O), plus we stock non-mineral
  oils (the K) such as silicone oil, synthetic
  esters and natural esters. The flash point is
  the differentiator.

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• Thus by way of example KNAF designates a
  non-mineral oil filled unit (likely a synthetic
  ester) that has natural convection flow in the
  tank and utilizes fan cooling externally.
• Of special interest to Benzoil is the first
  letter, O or K. Benzoil supplies standard
  mineral oils (the O), plus we stock non-mineral
  oils (the K) such as silicone oil, synthetic
  esters and natural esters. The flash point is
  the differentiator.

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• Note that some technical literature refers to
  fire point, and some to flash point. There is a
  subtle difference, and the fire point is always
  higher that flash point. For the avoidance of
  doubt, IEE Standard C57.12.00 makes reference to
  fire point.

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• By definition the flash point of a volatile
  liquid is the lowest temperature at which it can
  vaporize to form an ignitable mixture in air.
  The fire point is the temperature at which the
  vapour continues to burn after being ignited.

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• There are environmental, health safety and
  performance benefits of K-oils over O-oils, so
  ask Benzoil about changeouts, retrofills and
  transformer oil replacement programs today. High
  flash point fluids we supply are suitable for use
  in transformers in hazardous locations where fire
  or explosion hazards exist. This may be due to
  the presence of flammable gases and vapours,
  combustible dusts, or ignitable fibres present
  producing ignitable mixtures. We stock the
  following

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• Natural ester oils
• Formulated from edible seed oils and bio-based
  feedstocks (canola, soybean), natural ester
  dielectric fluids are sustainable and renewable
  providing sustainable environmental protections.
  Examples include
• Envirotemp FR3
• Midel 1204
• Midel 1215
• NeuGen Plus

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• Synthetic ester oils
• Synthetic esters are manufactured by combining
  alcohols and carboxylic acids in an
  esterification reaction. The sophisticated
  chemistry allows the formulator to design oils to
  meet any insulating challenge. Although not
  quite natural, synthetic esters do still exhibit
  the favourable health, toxicity and environmental
  benefits of more natural oils. Examples include

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• Envirotemp 200
• Midel 7131
• Dow Corning 561
• Nycodiel
• All the K-type oils have the required fire point
  (and flash point) over 300 degrees, so are
  suitable for any O to K oil replacement project.
  Ask for our advice today.