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Re: can you use spark plug wires??

Subject:     Re: can you use spark plug wires??
       Date: Mon, 5 May 1997 09:44:48 +1200
       From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Organization Wellington Polytechnic, NZ
         To: tesla-at-pupman-dot-com


Hi all,
          Begging to differ somewhat to Alfred's reply to William....

>   From:   "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
>     To:   Tesla List <tesla-at-pupman-dot-com>
> 
> 
> On Thu, 24 Apr 97 06:12:28 UT William Noble
> <William_B_Noble-at-msn-dot-com> wrote;
> 
> > while reading about kick back killing neons, it dawned on me that
> > typical automotive spark plug wire is a carbon core with 30KV insulation
> > around it. It is designed to suppress all sorts of stuff yet pass a decent
> > current.  It seems to me that the neon to capacitor connections could be
> > made with this wire, with the following benefits:
> 
> The biggest drawback of using spark plug wire is the resistive losses
> They are made of carbon to increase their resistance, in a Tesla Coil 
> this will only increase your losses.

I think he was proposing to use them to run from the neon to the caps.
A lot of people use some series R here to kill the Q of 
chokes/parasitic Ls and Cs etc.
  
> > 1. protection of the neon(s)
> 
> No protection what so ever, it wold be like expecting a several 100K 
> resistor to protect the neon transformer - it wont.
> 
> > 2. RF suppression for 60HZ line
> 
> To the best of my knowledge spark plug wire has no inherent 
> suppresion of R.F. it is the ignition coil circuitry that 
> incorperates R.F. suppresion.

Well, the resistance helps kill Q in the ignition circuit doesn't it? 
You get a bit of the R-C filter syndrome at work.
     I suspect the scheme is nogo because the average power level the 
leads will have to handle will cook them. They are not designed to 
dissipate much at all.

Malcolm


> > 3. protection of the user due to good HV insulation
> 
> Better insulation than say house wire or other wire designed for low 
> voltage. Try neon sign wire it's insulated to at least 50KV and has 
> much better conductivity. You could also consider test probe wire 
> it's usually good to at least 35KV. I will assume you are considering 
> usage for small Tesla Coils like say under 1 Killowatt because over 1 
> killowatt spark plug wire, neon sign wire, and test probe wire has 
> too small a cross sectional area for 1 killowatt you should be using 
> something like #10 gauge stranded (for flexability) and over a 
> killowatt the required thickness goes up!
> 
> > 4. cheap
> 
> Last time I checked bothe test probe wire and neon sign wire were 
> much cheaper than spark plug wire.
> 
> > 5. no inductors to build
> 
> Not true since the spark plug wire is nothing more than a long 
> resistor you will still have to add chokes and capacitors to supress
> the R.F. .
> 
>                                Sincerely
>                       
>                            Alfred A. Skrocki