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How inductor limit inrush current

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dinupaulson

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Hi Friends,
I have Lenard how the inductor behaves when the current changes through it. But I would like to know how to figure out the component values for it, I mean How to select a Inductor value to limit inrush current.

Suppose the inrush current rating is 100Amps/200uS. 230V AC inductive load.
 
V= L di/dt can give induced voltage in the inductor, But how can I select inductor limit the 100A to a lower value( 5Amps)
 
Hi,

The max current peak possible is Vpeak*2/(w*L). However, the inductor will not only limit the inrush current it will also limit the steady state current so you'd have to select the value so that it doesnt change the original current draw too much.
So what this means is that if you have a device that draws 5 amps normally but has a 100 amp inrush, you'd have to select an inductor that limits the inrush to maybe 20 amps or something so that after the inrush period is over the device still operates normally.

Also, when using inductors you have to be careful not to disconnect them suddenly from a circuit or they could blow out other components, even switches.

You may be able to use an inductor and some sort of switching circuit that shorts out the inductor after the inrush time is over.
 
Last edited:
when you select power inductor, you should be consider Isat and Irms what are DC current, inductance will drop off at Isat and temperature will raise at Irms.
when you select PFC inductor, you need consider inductance at DC current.
when you use common mode choke and difference mode choke, you will think Irms, if the coil can pass Irms.
 
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