In my circuit I want to use inductor having value 330uH. So instead of connecting a single inductor, I prefer to connect 4 inductors, two of them in series two make it 660uH and another two in parallel with the last two of them to make it again 330uH. This is it if we are talking about only inductance but waht about saturation current. Using this connection how it would affect the saturation current of the indductors? Will I actually get 2 x 4amp = 8amp Isat?
For a little bit of time, consider this one as a cheaper than using a single inductor. What are the pros and cons for doing this??
Electronic – Effect of Isat on inductor when connecting four inductors in a combination
inductor
Related Solutions
Two inductors in series would still saturate at 10A and also you'd have twice the inductance. Two inductors in parallel would share the current reasonably well but now the net inductance has halved because they are in parallel.
This would mean you choose inductors that are twice the inductance and this has a net benefit because, for a given ferrite size/mass, getting twice the inductance only needs 1.414 (sq root of 2) times the number of turns and flux saturation is driven by amperes x turns.
So you started with 1 x 10uH inductor saturating at 10A and you end up with two parallel inductors of 14.14uH each saturating at 7.07A but because they are in parallel the net saturation current is 14.14 amps.
Small print: Assumes that the two inductors are well-matched i.e. reasonably share the load current and that they don't leak enough flux to each other to make calculations more complicated.
It depends totally on the core material. Generally, ferrite core materials, as they get warmer, increase their permeability which increases the inductance. Compare 3C90 and 3F4 from ferroxcube: -
Both increase their permeability (and hence inductance) as they warm from -50ºC to about +100ºC. 3C90 then drops a bit before resuming its upward journey until it reaches its curies point at about +200ºC. 3F4 never reduces its inductance until the curie point is reached.
Iron-powder cores may behave differently and there are certainly ferrite cores that exhibit a stronger negative trend in permeability w.r.t. temperature in some areas of their characteristic.
What inductor are you using and what is the circuit in which it is used in?
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Best Answer
If the saturation current of a single 330uH inductor is 2A, then having two in series will still saturate at 2A.
Having two series strings in parallel means the strings as individuals will saturate at 2A but because they are in parallel the circuit combination will saturate at 4A.
Make sure they are not closely coupled or the inductance values will change due to coupling magnetic fields to each other.