[Amps] Edge wound inductors

[garyschafer at comcast.net]

I assume that you are comparing an edge wound inductor height to that of a similar height round  wire. By shaving off the sides of the wire to make it a flat edge wound coil wouldn't you be reducing the surface area of the edge wound coil? Won't that increase resistance?
If you make the edge wound inductor material higher then that would increase the turn to turn capacitance.

Why would eddy currents be lower in an edge wound inductor?

73
Gary  K4FMX

-------------- Original message -------------- 
From: "Tom W8JI" <w8ji at w8ji.com> 

> > Isn't it mostly about being able to make a really good 
> > sliding contact 
> > to the two flat sides? 
> 
> The factors that affect optimum form factor of an inductor 
> would fill a good sized book, but the edge wound tape does 
> two good things besides the obvious mechanical tap 
> attachment advantage. 
> 
> First, the turn-to-turn center spacing can be smaller 
> without increasing turn-to-turn capacitance to the value of 
> tubing. Turn-to-turn capacitance kills Q in high reactance 
> inductors. A more compact length increases mutual coupling 
> from end-to-end and reduces inductor physical length for a 
> given inductance and current rating. 
> 
> Second, eddy currents decrease. This also increases 
> inductance for a given size and reduces heat and loss 
> resistance. 
> 
> Measuring edge wounds and tubing or round wire in a good 
> test fixture with good gear at HF, I find edge wounds have 
> about the highest Q of any inductor I've ever 
> tested...generally up in the area of Q=1000. 
> 
> While we can do very well with tubing in low or moderate 
> reactance inductors and we might not need the additional 
> component Q when the operating Q of the system is low, there 
> isn't much bad about them and they are easy to find and easy 
> to work with. They even work well in the rain. 
> 
> 73 Tom 
> 
> 
> 
> 
> 
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