Which scenario typically utilizes forced cooling by fans in transformers?

Forced cooling by fans in transformers is typically utilized during high-load conditions to prevent overheating. Transformers generate heat due to electrical losses, and this heat needs to be managed to maintain operational efficiency and safety. Under high-load conditions, the amount of heat produced increases, making it essential to implement additional cooling measures to ensure the transformer does not exceed its temperature limitations.

Using fans to enhance air circulation helps dissipate heat more effectively than natural convection alone. This forced cooling mechanism allows the transformer to operate safely and reliably under increased power demands. Consequently, it prevents potential damage to the insulation and other critical components, thereby extending the lifespan of the transformer.

In contrast, during maintenance checks, the transformer may not be under peak operational stress, and forced cooling may not be necessary. When the transformer is turned off, there is little to no heat generation, which eliminates the need for cooling. Lastly, in low-power applications, the heat produced is often manageable through passive cooling methods, reducing the necessity for forced cooling systems in those scenarios.