Fan unit with switch/thermostat

What are the main performance differences between the standard oil-based fan of a fan unit with switch/thermostat and the optional ball bearing fan?
There are several major differences in performance between the standard oil-based fans of fan units with switches/thermostats and the optional ball-bearing fans, which use oil-containing bearings for rotation and are filled with an appropriate amount of oil to reduce wear and noise and increase service life. However, its friction coefficient is relatively large, and its life is limited by the amount of oil in the bearing and the quality of the oil. The fan shaft is supported by ball bearings, and the rolling of the balls is used to reduce friction, thereby reducing noise and increasing service life. Ball bearings have strong wear resistance and load-bearing capacity, making the fan operation more stable and reliable.
Although oil-based fans reduce friction and wear to a certain extent through their built-in oil, over time, these oils will gradually be consumed or deteriorate, resulting in a decrease in lubrication effectiveness. When the amount of oil is insufficient or the quality of the oil is poor, the friction between the rotating parts of the fan will increase significantly, thereby accelerating the wear process and greatly shortening the overall service life of the fan. Therefore, for equipment that requires long-term stable operation, such as server racks, regular maintenance and oil replacement are essential to extend the life of oil-based fans. In contrast, ball bearing fans are known for their superior wear resistance and stability. Especially the double ball bearing fan, its design makes the balls roll in the bearing with very little friction and almost no wear. This design not only extends the life of the fan, but also reduces heat and noise caused by friction. It is estimated that dual ball bearing fans can operate continuously for 60,000 to 100,000 hours under ideal conditions, making them ideal for applications that require long-term, high-load operation, such as data centers, industrial production lines, etc.
Since the friction coefficient of the oil-based fan is relatively large, and the lubrication effect of the oil changes with time and usage conditions, the fan may produce greater noise at high speeds or under heavy loads. Additionally, when engine oil fails or is insufficient, noise problems may be further exacerbated. This may cause certain interference in situations where a low-noise environment is required, such as offices, data centers, etc. Ball bearing fans are popular for their low noise characteristics. The double ball bearing design makes the fan rotate more smoothly and reduces noise caused by vibration and friction. Even at high speeds and under heavy loads, the dual ball bearing fan maintains low noise levels, providing users with a quieter working environment.
Because their cost is relatively low and they can meet general cooling needs, oil-based fans are usually used in situations where noise requirements are not particularly high and the fan speed is low. For example, in some home appliances, small computers or low-cost server racks, oil-based fans are a standard option, which is both economical and practical. For occasions that require high-speed operation, high load, high stability and reliability, such as large server racks, data centers, industrial production lines, etc., ball bearing fans, especially double ball bearing fans, have become the first choice. These occasions have extremely high performance requirements for fans, which require the fans to maintain stable speed and heat dissipation over a long period of time while minimizing the impact of noise and vibration on the equipment. Therefore, although the cost of a ball bearing fan is relatively high, its excellent performance and long-term economic benefits make it an ideal choice for these occasions.
The oil quantity and quality need to be checked regularly, and engine oil added or replaced as needed to ensure normal operation. Basically no maintenance is required, just regular cleaning. However, after long-term use, the noise of the ball bearing fan may increase slightly, but the problem can be solved by adding grease.