Re: [TCML] Critical Coupling?

[bartb <bartb@xxxxxxxxxxxxxxxx>]

Yeah John. But also, the terms "critical" and "optimum" coupling are one 
and the same in radio engineering (such as antenna theory.. depends on 
text book). So really the confusion is due to TC's using these terms. 
With regards to coupling and Tulbury's k of 0.2, it's kind of 
interesting. I guess a coil might be made to have an optimum coupling of 
0.2 if the geometry is right for the emf. Maybe that is what he is 
attempting. However, that dog won't hunt. Coilers are going to build 
coils with sparks at their forefront and not coupling. They are going to 
adjust coupling to what suits their coil geometry and not the other way 
around. At least, that has been the past, and due to that, yes, coupling 
will vary.

Take care,
Bart

futuret@xxxxxxx wrote:
>  Dex,
>
> I personally don't use the term "critical coupling" to
> express the optimal coupling of a SGTC.  I think it can
> cause some confusion.  I prefer to use the term
> "optimal coupling".  I agree with you that this optimal
> coupling value will vary for different coils.
>
> Cheers,
> John
>
>
>
>  
>
>
>  
>
>  
>
> -----Original Message-----
> From: Dex Dexter <dexterlabs@xxxxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Fri, Jan 15, 2010 1:50 pm
> Subject: Re: [TCML] Critical Coupling?
>
>
> Indeed I suspect too  "critical coupling" means 
> something different for coilers than in radio theory.
> I don't think it stands for "magic k" values either.
> I guess you are right and that it denotes  the
> highest coupling in practical SGTC designs before
> insulation problems are faced.
> In Tilbury's book "The ultimate TC design and
> construction guide" (pp 108-113) he refers to the
> value k=0.2 as the critical coupling.
> Quote from the book:
> "A dashed line appears at k=0.2 in the worksheet 
> graphs and in the figures 4-19 through 4-24 denoting
> the critical coupling fot spark gap tesla coils.
> The worksheets can be used to design any type of coil;
> however,the critical coupling threshold of k=0.2 
> applies only to SGTCs."
>
> Frankly,fixing value k=0.2 for all designs of SGTCs
> ,all primaries and secondaries has got no sense to me.
> Moreover,insulation problems also depend on the bang
> size.With k<0.1 the insulation problems can be induced
> if the bang size gets too large for the coil size and
> the various flashovers ,or if you are lucky ,just 
> secondary racing sparks will happen.
>
>
>
> Dex   
>
>
>
>
>  
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>   
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