For inrush current limitation of a 500uF capacitor @540VDC (2 series connected 1000uF 400V rated caps.)
I use 5 Ohm NTC with a stedy state current of 30A. The capacity of the NTC is 270J.
At first I thought, I place the NTC away from the cooling fan. So that it can have the least resistance.
But then. I imagined. What happens if the user switch off the device and switch it on rapidly. ex in 1 sec.
My NTC is hot and had no time to cool. So it is possible that a very high inrush current flows.
So I came up with the idea that I cool my NTC. I place it downward on the pcb where the air flow.
But this time I suspect that I should not cool too much. Because if I cool too much it can not have low resistance and the efficiency of the circuit is worse.
If someone switch the device rapidly off and on, The fan will not stop.(because of momentum). The caps will not have time to discharge and the NTC will cool down rapidly because of the momentum of the rotating fan just in that 1 second that the user switched the device off and on.
I konw the idea sound not pretty cool, But I wanted to hear the opinions if I leave it upside of the pcb where there is no air flow, or place it on the downside of the pcb with air flow but with some enchancement that it will not be cooled completely. (a controlled cooling where the temp does not go down too much but goes down rapidly through the momentum of the fan when current is cut off)