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The selection of motor lubricant depends on factors such as bearing type, speed and temperature, and load. Generally, rolling bearings are lubricated with grease, and the bearing temperature of motors should typically be kept between 65°C and 80°C. When the bearing temperature is below 70°C, it is possible to go for an extended period without replenishing the lubricant. However, when the bearing temperature exceeds 70°C, the lubricant ages and deteriorates more rapidly, it may liquefy, evaporate, or be lost, which leads to increased friction and wear on the bearing. As a result, the interval between lubricant top-ups needs to be shortened; failure of the bearing will occur if the lubricant is not replenished in time. By using centralized oil mist lubrication, it is ensured that all lubrication points are lubricated in a timely manner; at the same time, the heat generated by friction from the lubricating oil is eliminated, allowing the bearing temperature to drop by 10–15°C. Moreover, since the same pipeline is used for the lubrication of the pump, centralized management becomes easier. However, since the motor uses oil mist lubrication, there are concerns that, due to poor sealing, oil mist may enter the stator; when the motor coils are surrounded by this oil mist, it can lead to damage to the coil insulation or overheating of the coils, until a failure occurs. In July 2015, Shenyang Jiayi Oil Mist Technology Co., Ltd. successfully tested motor oil mist lubrication in the gasoline hydrogenation unit of the Qingyang Petrochemical Branch; the maximum temperature of the motors reached 60°C, which reduced the bearing failure rate by 85%. Tests on oil mist lubrication of motors have shown that the oil/air mixture is essentially below the sustainable combustion point, and the epoxy resin motor winding material does not deteriorate in an oil mist atmosphere. At the same time, the new motors that comply with API610 standards are designed with full isolation between oil mist and the motor windings, preventing oil mist from reaching the windings. Therefore, the motor can be lubricated with oil mist, and its temperature can drop by more than 15°C.