What contaminants are removed by a transformer oil purification machine?

A purification machine removes free and dissolved water, entrained air, and solid particles. Many systems also reduce oxidation by products and lower dissolved gases through vacuum degassing. Fine filtration captures fibers, sludge, and metal particles that reduce BDV and clog cooling paths. By removing these contaminants, the system restores dielectric strength and improves heat transfer, delaying insulation aging and reducing risk of internal discharge.