Converter In-Rush Thermistors etc, UPDATE -4

ktmrfs wrote:

BFL13 wrote:
There will be no hot restarts! :)

The steady state current is 13a AC with 124v clean Honda inverter gen input. Load is DC 100a at 15v while the steady input is going.

I need at least a 15a thermistor for the steady input current, and that has lots of Joules, probably more than required, so that leaves R. (and we are using 20 or 25a thermistors anyway---bags of Joules.

No need to be fussy, arm wavy WAG is fine with maybe a range of possible in rush current limits desired, knowing there are the usual diodes and such in there and the 2400uf capacitors, same as other converters. So the transformer specs can be guessed within reason, since it works in there?

so how hard can it be to get a wildly approx. "desired in-rush current limit" and so get an approx. R ? Nobody's professional reputation is at stake here :)

If we get several answers, they can be averaged for perfect accuracy!

Not having any schematics I'll be what I think is conservative. course schematics may prove me either ultraconservative, or heading for disaster. So here goes a VERY WAG. Normally I wouldn't hazard a guess without more info but here goes.

I'd shoot for a surge current of double max steady state current, or around 30A at 25C. Then do all the calculations and see if there is a thermistor that has adequate ratings. I'd shoot for a device with J= at least 50% greater than calculated joules, and a max steady state current capability of 20A.

If you can't find a device that satisfies all the requirements at 30A, then go for no more than 45A surge limit.


Curious to see what Ken might come up with.

We will see if I need to eat crow or not and how it compares to what the mfg comes back with.