Inductors in Series, increased Current handling? - Page 1
Forum section: electronics / beginners

author: made2hack
author_rank: Frequent Contributor
timestamp: March 16, 2014, 10:06:21 am
content: @ALL,We know that inductors connected in series have their inductance added together, like resistors.So a 100uH + a 47uH inductor in series gives us an inductance of 147uH.But what of the rated maximum current value?Consider the following Murata axial power inductor:MURATA Axial InductorThe 18104C has an induction value of 100uH, a max DC Amp of 1.2A and a DC Resistance of 100m?. The 18473C has an induction value of 47uH, a max DC Amp of 1.65A and a DC Resistance of 55m?.If instead of using the 100uH, and putting two 47uH in series, will I now get a higher AMP rated inductor, with a slightly larger resistance of 110m?? Able to handle 1.65A? (Yes, the inductance would be 94uH as opposed to 100uH).And what if I chained the 100uH + 47uH, would I get 147uH with the lower amp rating of 1.2A?Thanks,

author: made2hack
author_rank: Frequent Contributor
timestamp: March 16, 2014, 10:24:17 am
content: So if instead of using one 100uH inductor with max rating 1.2A, I use 2 47uH inductors with max rating 1.65A, I will get a 94uH inductor with 1.65A Rating?

author: electronics man
author_rank: Frequent Contributor
timestamp: March 16, 2014, 02:43:08 pm
content: to increas the maximum current you have to put them in parallel

author: c4757p
author_rank: Super Contributor
timestamp: March 16, 2014, 03:08:46 pm
content: Quote from: trs80 on March 16, 2014, 10:24:17 amYes.

author: richard.cs
author_rank: Super Contributor
timestamp: March 17, 2014, 10:37:38 am
content: What you describe in your post is correct but the title is misleading.You are using two inductors that each have a slightly higher current rating because they are wound with fewer turns on the same core allowing thicker wire. But this will likely cost more and definately be more bulky than a single higher-rated inductor on a slightly larger core (allowing thicker wire).

author: made2hack
author_rank: Frequent Contributor
timestamp: March 17, 2014, 11:16:53 am
content: @richard.cs - Yes, you are correct, however, I don't know how I would have titled it differently?

author: Holograph
author_rank: Regular Contributor
timestamp: March 17, 2014, 01:51:46 pm
content: Quote from: trs80 on March 17, 2014, 11:16:53 amThe title as-is suggests that you're asking if taking two identical inductors and putting them in series increases their current handling, which it doesn't. It's correct if what you're actually comparing is one inductor vs two smaller-inductance-but-larger-gauge inductors (but you were incorrect in your assumption in the first post, though that part's been answered already).If you only had one type of inductor (this works with many other types of parts too really) available and wanted more current/power handling AND the same inductance, you'd use some number to the power of two of them in a series-parallel configuration. e.g. you could use 4 to double the current handling (and quadruple the power handling) by putting 2 in parallel in series with another 2 in parallel. To go up even more, 3 in parallel in series with another 3 in parallel in series with 3 more in parallel. It's not cost-effective to scale things like this, but it can be handy for prototyping if you don't have beefier parts available.