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by psb5 30 days ago
"Pouring water over transformers". Does this actually do anything?
2 comments

Yes I mean besides the risk of arcing and getting people shocked yes it should help cooling them down (through evaporative cooling)
Depending on the humidity, yes. The evaporation will cool them down, but if it gets humid enough it stops
> if it gets humid enough it stops

It won't stop if it's ventilated with outdoor ambient air:

40C air can hold 51 g of water per m3 of air. 60C air can hold 130 g of water per m3 of air [1]. The curve is exponential.

So, it works as long as the transformer is hotter than ambient air, even at the most humidest (100% RH). The transformer's heat will drop the relative humidity of the air near its surface, and the heated air can absorb more water again.

If the humidity is below 100% RH, what changes is that the evaporating water could cool it to below ambient air temperature, same effect as in swamp coolers.

[1] https://www.engineeringtoolbox.com/maximum-moisture-content-...

Ah interesting!! I knew there was some relevant interaction with temperature, but was too lazy to look it up. Thanks for clarifying it!