Answer / bimal ch b orah

onan means oil natural air natural
onaf means oil natural air forced
ofaf maens oil forced air forced
DYN primary is connected in delta and secondary is
connected in star

Answer / pillay

Answers #1 & #2 is correct but i can add something for the the benefit of some.
In ONAN the oil in the TX former circulates on its own due to hot oil goes up & cooler oil goes down.The TX former is cooled by just the air around it.
In ONAF the oil circulates as above but a fan is used to cool it.
In OFAF the oil is pumped with a pump for circulation and the air is cooled by a fan.
In DYN the primary winding of the tx former is wound in delta and the secondary is wound in star with tapping for neutral connection.

Answer / zahid

onan means oil natural air natural
onaf means oil natural air forced
ofaf maens oil forced air forced
DYN primary is connected in delta and seconday is connected
in star with neutral

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