What is the difference between oil and dry transformers?

The difference between oil and dry transformers primarily lies in their cooling and insulation methods. Oil transformers use oil as a coolant and insulator, allowing for high thermal conductivity and efficient heat dissipation, which is essential for larger power applications. They are typically sealed and can be placed outdoors due to their robust construction but require regular maintenance and oil purification to ensure longevity and performance. In contrast, dry transformers utilize air for cooling and solid insulation materials, making them ideal for indoor applications where space is limited or where environmental concerns prevent the use of oil. They are typically less costly to maintain as they do not require oil treatment, but they usually have lower power ratings compared to oil transformers. Overall, the choice between oil and dry transformers depends on application needs, environmental conditions, and maintenance considerations.