What materials are used for insulation in a traction transformer?

Traction transformers use a combination of solid and liquid insulation materials. Solid insulators include paper, pressboard, and high-temperature-resistant materials like Nomex. The liquid insulation is typically mineral oil or synthetic ester fluids, which provide both insulation and cooling. These materials must withstand high electrical stresses and thermal variations. Advanced insulation systems may also use epoxy resins or silicone-based materials to enhance performance and durability under demanding operating conditions.