I’m looking at how to limit the inrush current of AC/DC converter and am a little unsure of the details. I’ve done a bit of research and it seems that having a thermistor in parallel with a TRIAC is a good way to go as it means that the thermistor limits current initially but, once power has been established I can switch a TRIAC to bypass the thermistor. This means that the thermistor can cool down while the circuit is running and I don’t have to wait for it to cool down, if the power is turned off, before I can turn my project on again.
I’ve had a go at designing a circuit but, I am unsure if it’ll work, how to size components properly and if there is a better way I should do it. I have attached it (please excuse the horrible drawing).
-ac inlet with fuse and filter
- push button switch. Swithing voltage max:250VAC, AC Switching current max:12A . http://www.schurter.de/var/schurter/storage/ilcatalogue/files/document/datasheet/en/pdf/typ_MSM19LA.pdf
- 2 Thermistors
- 2 TRIACS
- 1 resistor
- AC/DC converter SP-480-24 (20A, 24V) with inrush current 20A/115VAC and 40A/230VAC http://www.meanwell.com/search/sp-480/sp-480-spec.pdf
The circuit needs to work at 230 and 115 VAC.
Would this circuit work? How do I go about sizing the components? Is there a better way to do it? (I think I could probably get away with only using the limiting circuit on the hot wire of the AC input)
I’m also a little unsure on how to size the fuse on the AC inlet as well (Ihave yet to do some serious research into the issue). If you have any input on that too, it would be much appreciated.
Thanks for all the help