Re: Copper VS Steel

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

Hi Jim,

I'm sure that you will get a flurry of responses on this,
but I'll go ahead and reinforce the answer with mine.
First of all, any ferrous metal in the primary circuit of
a Tesla coil is a big "no-no". Iron and steel are very
poor conductors of RF currents and will really heat
up due to resistive heating. Also, as the spark gap
electrodes itself, steel will very quickly rust and cor-
rode.

Quenching refers to the spark gap's "spark" quickly
"going out" after it has fired to dischagre the capaci-
tor's energy into the primary coil. If it does not quench
properly, then the currents induced from the secondary
coil will back feed into the primary circuit and spark
gap and cause a significant decrease in the output, as
the spark gap's rapid switching is adversely affected. A
poorly quenched spark gap will have a yellow or pur-
plish "halo" around the super-bright blue-white spark
core. You do not want the flaming halo around your
spark, only the snappy blue-white core. Trying to
switch too much power for the spark gap design
will cause poor quenching. As the power processing
increses, the spark gap must employ more agressive
cooling techniques - more spark surface area, forced
air cooling, mechanical seperation (rotary spark gap),
ect. to be able to properly "quench".

Hope this helps,
David


----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Monday, March 12, 2007 10:05 PM
Subject: Copper VS Steel


> Original poster: Jim <branley1@xxxxxxxxxxx>
>
> Hi Folks:
> I do appreciate the great assistance with my tesla coil that I have
> received from you.
> Can I get your opinion on a few things?
>
> 1) Can I use 1" EMT (Electrical Metallic Tubing) for my spark gap
> instead of 1" copper pipe?
>
> 2) Can I use zinc coated bolts and nuts for my secondary instead of
> brass bolts and nuts? Zinc is what most bolts, nuts & washers are coated
with.
>
> 3) What does the term quenching refer to when speaking about spark gaps?
>
> Thanks for the informative help!
> Jim
>
>
>