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Inrush current limiter

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Nihaludeen

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Hi friends, I am making an inverter circuit, when i connect the supply to the circuit spark produces. 2200uf capacitor is attached to my circuit, since it create inrush current(for few microsecond) which is too bad for any circuit.

So we temporarily use resister (manually connect and disconnect) to limit the current flow.
NTC thermister is one of the solution for it.(LOW watts appln)
My circuit spec,.. 40v and 30 amp(1000W)

Resistance of NTC,

Rmin=V/I limit = 40v/90amp = 0.44ohm ntc resistor

I confused in selecting the value of resister.Is the above calculation is correct.
 

Hi,

one solution could be to use a PFC stage with soft start feature.

Klaus
 

You need to read the data sheet and see what the resistance of the ntc will be for the normal current in the inverter.

NTC's run at >150C so be careful where you put it in ckt and have it on long leads to avoid burning the pcb.

A 1 ohm or 4 ohm ( 25C) ntc (31mm dia) may be OK fr your app depending on the normal standing current of the inverter and this will limit the peak inrush current to 40A / 10A respectively ...
 

Easy peasy said:
You need to read the data sheet and see what the resistance of the ntc will be for the normal current in the inverter.

NTC's run at >150C so be careful where you put it in ckt and have it on long leads to avoid burning the pcb.

A 1 ohm or 4 ohm ( 25C) ntc (31mm dia) may be OK fr your app depending on the normal standing current of the inverter and this will limit the peak inrush current to 40A / 10A respectively ...
Click to expand...

Hi dude,
I have a power source that is capable of producing 30amp safely, but when i connect to the inverter circuit. More amount of current will be forced to charge the 2200uf capacitor. So i want to use inrush current limiter, but i not sure how much current flow is forced to charge the capacitor(I am not having oscilloscope). So i assumed that triple amount current will be inrused to charge the capacitor. Is my assumption is correct?
Then if i use 10-ohm NTC,
I=40/10= 4amp
Is that is enough? Will it produce spark?
 

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