Tørtype

Tørtype refers to electrical transformers that use solid insulation instead of liquid oil for cooling and insulation. They are designed to operate without oil-filled windings, which makes them suitable for indoor installations and environments where fire safety and oil leakage risks must be minimized. Tørtype transformers are commonly used in commercial buildings, data centers, hospitals, and industrial facilities where space, safety, and maintenance considerations are important.

Construction and cooling are based on windings cast or encapsulated in epoxy resin or other solid insulating materials, often with a laminated steel core. Cooling is achieved through natural air convection or forced air cooling, sometimes with fans or air-to-air heat exchangers integrated into the enclosure. The insulation system may use varnishes, resins, or encapsulation techniques to withstand temperature rises during operation. The design can include cast resin windings or resin-encapsulated windings, which contribute to moisture resistance and mechanical robustness.

Variants of tørtype transformers include cast resin dry-type and encapsulated dry-type configurations. Cast resin types embed windings in solid resin blocks for high mechanical strength and moisture resistance, while encapsulated types offer additional containment against dust and environmental contaminants. Cooling classes for dry-type transformers are typically tailored to indoor use and specific load profiles and may use natural or forced air convection.

Advantages of tørtype transformers include enhanced fire safety, reduced environmental risk from oil leaks, and suitability for indoor installation. Limitations often involve higher losses and material costs at equivalent ratings compared with oil-filled transformers, as well as potential weight and mounting considerations. Standards governing dry-type transformers, such as IEC 60076-11, address performance, insulation, and safety requirements.

Overall, tørtype transformers provide a safe and reliable option for electrical distribution where oil-filled designs are impractical or undesirable.