Re: Aluminium Wire (fwd)

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Date: Fri, 28 Sep 2007 18:35:47 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Aluminium Wire  (fwd)

In the bottom on the DC end of things a resistor could be used to 
simulate. But not so easy on the AC side. I did a simulation last night 
as a comparison with Javatc. In both RDC and RAC equations, the 
resistivity of copper is defined. I simply changed the resistivity so 
that the system properly looked at aluminum. In both cases each 
resistance went up 1.6 times.

How this effects the coil is in losses in the secondary and also affects 
ring up. Oh, it will work just fine. No ones denying that, but losses 
will increase. It's similar to winding say a 1600 turn coil compared to 
a 1000 turn coil. Both work just fine, but there is point where the 
losses start to become noticeable. The difference might only be 1 to 5 
inches of spark length, but it is still a loss. If the cost savings 
outweigh those minor inches of spark, it might be well worth it to wind 
aluminum secondarys. I'm not saying that we should or should not use 
aluminum but simply stating a fact of physics that losses increase with 
higher values of resistivity and inturn RF losses are further aggravated.

The 220k spark load is not related here.

Take care,
Bart

>
>    Couldn't this be crudely (lumped) simulated by  adding a series resistor 
>between the bottom of the secondary and the RF ground,  and another between 
>the top of the secondary and the topload? Say, 100 ohms each  resistor? Does 
>this really have a big effect on spark length?
>    It doesn't seem to have much effect on the spark  when a resistance is in 
>series off the topload. After all, the model is  something like 220,000 ohms 
>per foot of spark through *air*!
> 
>-Phil LaBudde
>
> 
>Center for the Advanced Study of Ballistic  Improbabilities
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