Small and medium sized __________ are self-cooled; that is, cooling takes place by direct radiation from the tank to the surrounding air.

Small and medium sized __________ are self-cooled; that is, cooling takes place by direct radiation from the tank to the surrounding air.

• A. Transformers
• B. Relays
• C. Switchgear
• D. Generators

Answer: (A)

The main idea is how certain equipment dissipates heat without using additional cooling gear. Small and medium transformers are designed to shed heat directly from their tank to the surrounding air. This self-cooled, natural cooling happens because the tank surface radiates and the oil/air convection around the tank carry away the heat without fans, pumps, or external radiators. That makes these transformers simple, reliable, and cost-effective for typical distribution loads since their heat generation is within what the tank surface can handle by just being in the ambient environment. The other options aren’t described this way: relays and switchgear aren’t meant to shed heat solely by the tank’s surface, and generators rely on separate cooling systems like radiators or fans, not heat dissipation directly from a tank to air.

The main idea is how certain equipment dissipates heat without using additional cooling gear. Small and medium transformers are designed to shed heat directly from their tank to the surrounding air. This self-cooled, natural cooling happens because the tank surface radiates and the oil/air convection around the tank carry away the heat without fans, pumps, or external radiators. That makes these transformers simple, reliable, and cost-effective for typical distribution loads since their heat generation is within what the tank surface can handle by just being in the ambient environment. The other options aren’t described this way: relays and switchgear aren’t meant to shed heat solely by the tank’s surface, and generators rely on separate cooling systems like radiators or fans, not heat dissipation directly from a tank to air.