Too much cooling air? (Power supply failures due to condensation)

In summary, the conversation discusses a situation where 36 power supplies are failing due to moisture, despite being located in a room with a temperature of 30C and relative humidity of 45%. The failures were attributed to condensation forming inside the enclosure, possibly caused by negative pressure and airflow from cooling fans. The person requesting assistance has decades of experience designing power electronics but has never encountered this issue before. Additional questions are asked regarding the room's conditioning, temperature, and the possibility of relocating the cooling fans.
  • #1
powerelect
1
0
TL;DR Summary
condensation and dew point in electrical cabinet with high velocity air
I have a situation that I cannot explain so I need the assistance of someone with a good understanding of thermodynamics.

I have 36 AC to DC power supplies located in an equipment rack. These power supplies are failing after some time. The failures appear to be moisture related. We put moisture indicating labels in the power supply and their color changed indicating the presence of moisture.

We replaced the metal cover on the power supply with clear plexiglass and we also saw condensation form inside the enclosure after a number of hours. The environmental conditions were 30C and 45%RH. The dew point should be far below room temperature under these conditions. This was installed at a location close to sea level. There are large cooling fans on the cabinet door pulling air out of the cabinet.

So, the pressure inside the cabinet is negative. Could this large amount of airflow pulling through the unit cause the moisture in the air to condense? Could the negative pressure cause the dew point to drop? Can someone explain this? I have been designing power electronics for decades and have never seen this before.
 
Last edited by a moderator:
Science news on Phys.org
  • #2
Welcome, @powerelect ! :smile:

Is the room containing the panel conditioned?
If so, at what temperature?
Could you relocate the cooling fans to be blowing into the cabinet?
 

Related to Too much cooling air? (Power supply failures due to condensation)

What causes condensation in power supplies due to too much cooling air?

Condensation in power supplies can occur when the cooling air is significantly cooler than the ambient temperature, causing moisture in the air to condense on the cooler surfaces within the power supply. This is particularly problematic in environments with high humidity levels.

How does condensation lead to power supply failures?

Condensation can lead to power supply failures by creating short circuits, corroding components, and causing electrical insulation to break down. Moisture can bridge electrical contacts, leading to unintended current paths and potential damage to the power supply.

What are the signs that a power supply is failing due to condensation?

Signs of power supply failure due to condensation include intermittent operation, unexpected shutdowns, visible moisture or corrosion on components, and unusual noises such as buzzing or crackling. In some cases, you may also notice a burnt smell or visible smoke.

How can I prevent condensation in my power supply?

To prevent condensation, ensure that the cooling air is not excessively cooler than the ambient temperature, use dehumidifiers to control humidity levels, and consider using heaters or thermal pads to maintain a stable temperature within the power supply. Properly sealing the enclosure can also help prevent moisture ingress.

What should I do if I suspect condensation in my power supply?

If you suspect condensation in your power supply, immediately power down the equipment and disconnect it from the power source. Inspect the power supply for visible moisture or corrosion, and allow it to dry completely before attempting to use it again. If the problem persists, consider consulting a professional technician for further diagnosis and repair.

Similar threads

Thermodynamics is air ducts, dew point
Replies
2
Views
2K
Preventing Condensation in Outdoor Enclosure
Replies
2
Views
2K
Calculating saturation and dew point given pressure and temperature
Replies
4
Views
4K
How to reduce RH of air from evaporative cooler?
Replies
5
Views
6K
Atmospheric humidity for water production.
Replies
3
Views
2K
Dyson bladeless fan/turbine compressor building air cooling?
Replies
6
Views
8K
Are Isotopes in Ice Cores Indicators of Temperature or Precipitation?
Replies
2
Views
3K
Strong negative feedback in Climate
Replies
2
Views
5K
B Exploring Nuclear Fusion: IEC Fusion Reactor Construction and Operation
Replies
19
Views
4K
Solaculture: A novel biological approach for low cost energy?
Replies
4
Views
3K

Hot Threads

Recent Insights

Back
Top