Definition
The cooling method describes how a transformer dissipates the heat produced by its losses. It is codified by standardised letters: the first designates the fluid (A for air, O for mineral oil), the second the circulation mode (N natural, F forced).
A dry-type transformer with natural air cooling is denoted AN; with forced ventilation, AF. An oil-immersed transformer with natural circulation is denoted ONAN. The cooling method determines the power the unit can sustain continuously: forced ventilation often allows the permissible power to be uprated.
The choice depends on the power, the environment (indoor, dust, fire safety) and maintenance constraints.
The ABL tip
The right cooling method depends on your power and environment. For closed rooms or high power density, ABL Transfo can provide forced ventilation or dry, oil-free solutions, safer indoors.
