Re: [TCML] Stranded/silver plated wire (was Scientific Method)

[Quarkster <quarkster@xxxxxxx>]

DC -
 
Please explain what "not adequate" means, regarding 7 strand vs 19 strand wire of the same gage.
 
Why would the number of strands in a given size wire have any affect or influence on winding the secondary coil, the performance of the completed coil, cost, appearance, etc, etc.??
 
(It's these incomplete statements with no supporting information that are so frustrating to TCML readers!!)
 
Knowing that the immediate response of EVERY reader of your post will be "what possible difference can the number of strands make??", why not provide the missing information in your original post? 
 
Something like this would be far, far more useful:
 
"I use the 19 strand silver tinned type wire usually in 14 to 18 AWG on many
of my high power coils.  The 7 strand is not adequate because:
(for example)
 
"It is far stiffer than the 19 strand wire and does not conform closely to the the secondary coilform."
 
or 
 
"The 19 strand wire has 12% lower AC resistance than the 7 strand wire at the 125KHz resonant frequency of this particular 6" diameter X 32" long secondary."
 
Or whatever, just be specific! This is a technology forum, not a gardening forum where "Plant the seeds sometime in August, and water occassionally" is specific enough to get the desired results.
 
Regards,
Herr Zapp

 
 


--- On Wed, 7/29/09, DC Cox <resonance@xxxxxxxxxxxx> wrote:


From: DC Cox <resonance@xxxxxxxxxxxx>
Subject: Re: [TCML] Stranded/silver plated wire (was Scientific Method)
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Date: Wednesday, July 29, 2009, 6:34 AM


I use the 19 strand silver tinned type wire usually in 14 to 18 AWG on many
of my high power coils.  The 7 strand is not adequate.

Dr. Resonance




On Tue, Jul 28, 2009 at 8:44 PM, jimlux <jimlux@xxxxxxxxxxxxx> wrote:

> Lau, Gary wrote:
>
>> Are you saying that you use silver-plated STRANDED wire for
>> secondaries?  Granted, AC resistance and Q are far less important on
>> the secondary side, but the notion of this wire being superior to
>> common magnet wire is incorrect.  Stranded wire is inherently more
>> lossy at RF frequencies.  This is because the skin effect causes
>> current to travel on the outer surface of the bundle.  If a strand on
>> the outside of the bundle weaves to the interior of the bundle, the
>> current in that strand will try to find its way back to the surface,
>> and this means traveling to adjacent conductors, through any
>> resistive oxide layers between them.  This strand-hopping results in
>> a much higher AC resistance than if a single conductor were used.
>> This is the reason that Litz wire insulates the strands from one
>> another.
>>
>
> Most stranded wire is NOT braided. It's something like 7 strands, so the
>  outside strands stay outside. THe other thing is that 100kHz-ish
> frequencies have a fairly thick skin depth (0.2 mm in copper). It's not like
> at 15 MHz where skin depth is a few tens of microns.
>
>
>
>
>
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