Using a fan cooled power supply in a dusty or damp environment has the potential to lead to a premature failure.

Such failures are not covered by the manufacturer's warranty. Power supply cooling fans work by either blowing air into the power supply or sucking the warm air out.  

The blow in direction makes more efficient use of the fan and allows manufacturers to produce power supplies with a higher power density. However, this method of cooling has some drawbacks. 

Disadvantages of Fan Cooled Power Supplies 

Dust in the air is sucked in by the fan and gets caught in the wire mesh that protects the air inlet, as shown in the below image.

power_supply_cooling_fan_with_bloked_air_inlets

The amount of dust caught in the mesh accumulates over time, which causes insufficient air intake and has the potential to lead to a downgrade effect in heat dissipation. It can also trigger the “FAN LOCK” function, shutting down the power supply. 

Dust that enters and accumulates in the power supply can absorb moisture. When dust absorbs moisture, it can cause a drop in resistance across the copper tracks on the power supply’s PCB that can lead to arcing. 

arcing_caused_by_dust_and_moisture_entering_the_power_supply

Advantages of Passively Cooled Power Supplies 

MEAN WELL’s UHP series of fanless power supplies are a good option for applications where reliability is paramount.  

Passively cooled power supplies do not rely on a fan for cooling. This means that dust and moisture are not forced into the power supply. Additionally, there are no moving parts to fail.  

These power supplies are cooled by natural air convection and heat being conducted away through the power supply’s metal enclosure. To ensure adequate cooling the power supply needs to be mounted on a metal surface. MEAN WELL stipulates in the data sheets the minimum surface area required. 

The following table shows the range of models available within the MEAN WELL UHP Series. 

 *actual power output depends on the model selected, refer to data sheet for details. 

For further information on fanless power supplies please contact MEAN WELL Australia