4. Operating life. As the life of a cooling fan usually depends on the reliability of the motor bearings, ball bearing systems have been proven to have high efficiency and low heat generation. Fan bearings are generally available in double ball bearings (Ball bearing), single ball + single sleeve bearings, and oiled sleeve bearings (Sleeve bearing).
5、Tolerance level. Including temperature and humidity withstand, insulation and impedance withstand voltage. Some special cases also require a heat resistance rating under the temperature rise test, mainly related to the performance of the fan's insulation material, of which the heat resistance rating is divided into Y level 90°C, A level 105°C, E level 120°C, B level 130°C, F level 155°C, H level 180°C and H level above a total of seven levels.
6. Other details. For example, packaging methods, wire length, connector type and colour, etc. This is also a detail that needs attention to prevent mistakes from occurring and affecting production.
