Fan Life

The lifespan of a fan determines the lifespan of the equipment. This is because the lifespan of the parts used in the equipment is affected by temperature. If the lifespan of the fan is shorter than that of the equipment, the fan will need to be replaced as part of equipment maintenance. In the third hour, we will look at the lifespan of the fan.

What is the lifespan of a fan?

Generally, the lifespan of a fan is defined based on the point at which there is a "certain decrease in air flow capacity" or "certain increase in noise" after a certain period of continuous operation.

The catalog states the expected lifespan of the fan as follows:

"90% survival rate" and "L10" refer to the time that 90% of the total number of fans can continue to rotate normally. In other words, both have the same meaning and define a lifespan with 90% reliability.

SANYO DENKI CO., LTD. Denki considers a "decrease in air flow capacity beyond a certain level" to be a decrease in the fan's rotational speed, and defines the fan's lifespan as the time until the fan's rotational speed falls to 70% of its initial value.

■ Relationship between rotation speed and fan lifespan

Factors affecting fan lifespan

The more components an electrical product has, the more factors that affect its lifespan. When designing equipment, the equipment lifespan is sometimes defined as the MTBF (lifespan of electronic components).
However, in the case of fans, the lifespan of the structural parts, that is, the bearing parts in the motor that rotates the blades, has a greater impact than that of the electronic parts. There are many different types of bearing parts, but SANYO DENKI CO., LTD. Denki only uses highly reliable ball bearings.

There are two types of ball bearing life: fatigue life (peeling life) and grease life. Fans, unlike industrial motors, place a relatively small load on the bearings, so fatigue life is rarely an issue.
Therefore, the "grease life" of the ball bearings is the biggest factor that determines the lifespan of the fan.

How to extend the life of your fan

The lifespan of a fan is determined by the "lifespan of the grease," so extending the lifespan of the grease will extend the lifespan of the fan. There are four ways to extend this "lifespan of the grease."

1.Reducing bearing temperature
2. Reduction of bearing load
3.Improvement of grease
4. Improved load capacity of bearings

Points 2 to 4 are decided at the time of fan development, so it is difficult for users to improve them, but as for point 1, "reducing the bearing temperature," the same effect can be obtained by reducing the ambient temperature of the fan. For example, a fan with an expected life of 40,000 hours in a 60°C environment (*) will have an expected life of approximately 70,000 hours in a 40°C environment.
*For San Ace model number: 9GA0312P3K001.

Fans are primarily used for cooling, but if you understand that the fan itself is affected by the ambient temperature, you can select a fan taking the ambient temperature into account, which will lead to maintenance-free equipment.

SANYO DENKI CO., LTD. 's measures to extend the life of fans

The "grease life" of a bearing is the biggest factor affecting its expected life. Therefore, SANYO DENKI CO., LTD. has taken measures to extend the grease life, such as "reducing the bearing temperature" and "reducing the bearing load."

For example, as shown in Figure 1, by changing from a plastic frame to an aluminum frame, which has better heat dissipation properties, the temperature rise of the bearing can be suppressed, thereby achieving a "reduced bearing temperature."

This time, we learned about the lifespan of fans. In addition to the expected lifespan, when selecting a fan to use for cooling or blowing air, do you often compare maximum airflow and maximum static pressure? In fact, when a fan is installed in a device, it is not possible to achieve both of these performances.
Next time, let's learn together about "fan air volume-static pressure characteristics."

Supervised by: SANYO DENKI CO., LTD. Cooling System Design Department

release date: 2018-01-26 00:00