Lubricating oil generally consists of two parts: base oil and additives. Base oil is the main component of lubricating oil and determines its basic properties.Additives can compensate for and improve the performance of base oil, 　

For industrial gear systems, industrial gearboxes are now made of new materials, with lighter self weight, greater power generation, durability, and reliability, and higher gear teeth and bearing loads.　

The quality of variable pressure oil can only be identified through pressure test. But unqualified oil can be roughly identified from its appearance. Precautions for taking oil samples from transformers: