Are dry-type transformers filled with oil to reduce overheating?

Dry-type transformers are indeed not filled with oil as part of their construction. They operate using air as a cooling medium, which is why the answer is considered correct. The design of a dry-type transformer allows for effective heat dissipation through natural air convection rather than relying on any liquid coolant. This feature makes dry-type transformers particularly suitable for indoor installations and locations where reducing flammability is essential.

While oil-filled transformers utilize the oil for insulation and cooling, dry-type transformers maintain their functionality without any liquid filling. As such, options discussing oil, water, or alternative cooling methods do not apply to dry-type transformers, reinforcing the primary role of air in their thermal management.