Re: Aluminum wire in an NST

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sundog-at-timeship-dot-net>

Hi All!

  I depotted a Franceformer 15/30, and nicked the primary with the air
chisel (oopsie).  as I was filing the ends down to re-solder it, i realised
it was aluminum wire.  I had to resort to a mechanical crimp connection
(crapola), but other than that, there's no reason not to use aluminum.  It's
lighter, sure, a bit more resistive than copper, but cheaper, etc.  The
extra heat it makes in a NST must not be that much compared to copper, or
the extra heat is within appectable limits to the manufacturers.

  It's used in pole-pigs (my pig is aluminum foil wound) and I've had no
problems with it.  I have to agree that the losses of using it in the
primary would be negligible compared to the spark gap, and any surface
resistance at the connection won't survive a 20kv 200A+ blast when the tank
cap fires.   A good mechanical connection is obviously present in the pigs
and NST's, as I can't remember hearing of an NST that's died from a bum lead
connection to the primary, and a pig *has* to take chunky current on a 24x7
basis.   It would be interesting to wind an identical set of primarys and
secondarys for a VTTC using copper and aluminum wire to compare the
performance, but it's not on my plate.

 As for aluminum being a crap conductor...I can recall *many* a brush with
the electric fence wire when I was a kid, hurt like the dickens, but a day
later I'd forget and get tangled up in it again.  I figured it.  That wire
was aluminum, I'm not sure what the barb wire the second charger was hooked
up to was. but it seemed to work just fine!

            My 2%

Shad
----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, July 26, 2001 9:49 AM
Subject: Re: Aluminum wire in an NST


> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Hollmike-at-aol-dot-com>
>
> Hi all,
>    Just as a note,  Chip,  our list owner,  uses a (approx. 2 inch wide)
> aluminum strip cut from the end of a roll of flashing for his primary
coil.
> It seems to work just fine, in spite of all a theory that says it should
> suck.  The 10+ foot streamers that his coil produces rival the output of
any
> coil I have seen so far.
>   I think it works fine due to the large surface area.  It must alleviate
> any problems of lower conductivity.   As for contact resistance due to the
> oxide layer,  he taps his primary using a simple clamp(hemostats if I
> recall).
>    I only mention this, because this topic arises periodically and there
is
> much discussion about how bad aluminum is as a conductor.   I think the
gap
> losses are like an order of magnitude(or more?) higher than that caused by
> the resistivity of aluminum, or any conductor,  so the choice is not that
> critical.   Perhaps one reason not to use it for a primary coil is the
size.
> Unless the coil is a very small one, the wire from a NST primary is likely
> too small -whether it is copper or aluminum.
>    my $0.02
> Mike
>
>
>
>