Converter In-Rush Thermistors etc, UPDATE -4
UPDATE on 17 Nov, Update 2 on 22 Nov, Update 3 on 16 Jan 14, Update 4 on 19 Oct 14. --------------- In a recent thread there was mention of how you can wreck your gizmo (in my case a converter) ...
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Not sure if PowerMax has the "real answer" as they haven't gotten it right yet. Both their previous two design have gone up in smoke. And lately the "design by rv.net committee" approach (which I was not a part of) also smoked.
I've done an analysis similar to your link, what seems like weeks ago. The transformer does not come into play here. The inrush current goes through some emi inductors, the thermistor, a diode bridge and into the capacitor bank. The surge current must be less than the surge current rating of the diode bridge. We've done the calculation before. The ac resistance must be greater than 0.6 ohm. The 2 ohm thermistor is plenty big enough. More is not better.
Sal
I've done an analysis similar to your link, what seems like weeks ago. The transformer does not come into play here. The inrush current goes through some emi inductors, the thermistor, a diode bridge and into the capacitor bank. The surge current must be less than the surge current rating of the diode bridge. We've done the calculation before. The ac resistance must be greater than 0.6 ohm. The 2 ohm thermistor is plenty big enough. More is not better.
Sal
BFL13 wrote:
It has 2400 uF capacitors (two 1,200- 250v).
So is there enough there to go through the linked steps for a recommended thermistor? If so would appreciate seeing the results posted, even if different people come up with different results it might get us (or at least me! ) somewhere closer to a correct answer.
Then we can compare that with the real answer next week when PowerMax gets back.
Thanks
