Answer / mrinal

Onan – Oil Natural Air Natural
Onaf - Oil Natural Air Forced
Ofan - Oil Forced Air Natural
Ofaf - Oil Forced Air Forced

Answer / mick

it is the cooling method of a transformer

o = oil
n = natural means natural cooled i.e. by a radiator
a = air
f = forced means forced cooled i.e. with a fan

so an ONAN is a naturally cooled oil by natural flow of air
OFAF is oil is force cooled (heat exchanger) and the air is
forced (fans)

Answer / xyz

ONAN,ONAF, OFAN, OFAF all these are the types of cooling
arrangements required in a transformer to cool the windings
which get heated due to continues passing of current in
them.

Answer / mehedi islam aneek

The first letter designates the internal cooling medium in
contact with the windings.

O= mineral oil or synthetic insulation fluid with a fire
point ≤ 300°C
K = insulating fluid with a fire point > 300°C
L = insulating liquid with no me3asurable fire point.



The second letter designates the circulation mechanism for
internal cooling medium

N = Natural convection flow through cooling equipment
and in windings
F = Forced circulation through cooling equipment and
natural convention flow in the windings (also called
"directed flow")
D = Forced circulation through cooling equipment,
directed from the cooling equipment into at least the main
windings



The third letter designates external cooling medium

A = Air
W = Water



The fourth letter designates the circulation mechanism for
the external cooling medium.

N = Natural convection
F = Forced circulation (Fans (air cooling) , pumps
(water cooling))



For example: ONAN designates an oil filled unit that has
natural convection flow in the tank and utilizes natural air
convection cooling externally.



If this transformer has fans added for forced air
externally, the designation would be ONAF.



A transformer that has natural convection cooling as a base
rating and an elevated rating when fans were added later,
would be designated as ONAN/ONAF.



High fire point fluids use the designation of "K" for fluid
type. Thus a naturally cooled high fire point fluid would be
KNAN and the same unit with fans would be KNAF.

Answer / alan santos

IS A PART OF COOLING SYSTEM OF THE TRANSFORMER

Answer / nishi

Onan is oil natural

Answer / yims

The above answers are not far from the truth.  However 
ONAN is Oil-immersed natural cooling
ONAF is Oil-immersed forced-air cooling
OFAN is Oil-immersed forced-oil natural cooling
OFAF is Oil-immersed forced-oil forced-air cooling
......I trust this helps.

Answer / set ramachandran- kcet-eee-266

onan onaf ofan ofaf are the parts of the transformer i
think.anyway please inform me the corect answer.............

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