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Electronics => Projects, Designs, and Technical Stuff => Topic started by: T3sl4co1l on September 20, 2022, 10:55:02 pm

Title: Stranded (not individually insulated) wire for reduced AC losses
Post by: T3sl4co1l on September 20, 2022, 10:55:02 pm
Neat, there's a paper on it:
http://inductor.thayerschool.org/papers/stranded.pdf (http://inductor.thayerschool.org/papers/stranded.pdf)

I always figured it'd be good for ballpark 10-20% reduction in AC resistance (at frequencies where solid wire suffers skin/proximity effect losses); seems it can do quite a bit more than that, actually!

Mind, the difference, relative to ideal litz cable, is a factor of 5 or more (or, including arbitrarily deep proximity effect, and eddy currents from fringing fields, the sky's the limit..), but compared to solid -- it's something!

Probably a 10-20% figure is still ballpark reasonable for random hookup wire, that you don't have control over strand size/count and twist pitch; and in any case, you have the rather severe problem of wasted space due to thick plastic insulation.  But on a pound-for-pound basis, say on cores where you're not space limited -- relatively oversized cores, toroids -- that can be less of an issue.

Tim
Title: Re: Stranded (not individually insulated) wire for reduced AC losses
Post by: coppercone2 on September 21, 2022, 10:18:48 pm
well you can actually crimp it properly without crazy stuff so thats something
Title: Re: Stranded (not individually insulated) wire for reduced AC losses
Post by: Carel on November 14, 2022, 10:33:04 pm
I read this idea and tried it. Yes, it gave me an increase of 15 mm in range. With some tuning, thicker wire, some lower impedance I may get some more range. I am not familiar with the black magic of coils, this spoils a lot of wire, so I am not worthy of Litze wire at this moment.

Thanks!