Let me take a crack at this, so to speak.
Lightning isn't really DC, except maybe over a very small time delta - but
then so is AC current! Most lightning strikes I know of don't last too long
(fortunately).
Therefore it acts *just* like high frequency AC current - di/dt, for you
calculus fans, is really high. When is di/dt slow enough to be considered
DC? Hmmm.
All my texts on hand speak of skin effect as a "magnetic phenomenon", or
higher inductance in the bulk of the material, that keeps the current on the
surface - but I suspect this a Maxwellian answer to a solid state physics
problem. I would imagine that electron-level issues (generation and
recombination) play a role, not to mention plasma physics in the case of
lightning.
I'll shut up now. Physicists out there?
Yours pedantically, ;)
tim
-----Original Message-----
From: wizardz [mailto:wizardz@maxinter.net]
Sent: Friday, November 19, 1999 8:29 AM
To: Justin Cook; spridgets@autox.team.net
Subject: Re: Heater switch? -- Little LBC
I've never heard it called the 'skin effect' but so be it if you like
the termonology ... so be it.
High energy Magnetics proves the theory.
Then again...electron flow theory itself has never been proven
..it's all based on cause and effect. IE: we did this and it did that
Example: (and a question) When was the last time you saw an
"A.C. LIGHTNING BOLT" ? . ha !
Lightning is D.C. and will travel the surface of the tree, usually spiraling
down the tree just under the bark. (Lower resistance path than in the air)
If the spiral is tight enough, enough heat energy builds, boils the sap
(radiated energy
concentrated inside the coil) and the tree explodes. Otherwise
it just splits the bark in a spiral down the tree with little or no
immediate
damage to the heartwood
Paul Tegler
OBie - '73 BGT - Daily Driver
http://www.teglerizer.com/mgstuff/ob_description.htm
Rat -'80 Spitfire - fledgling recently left the nest
http://www.teglerizer.com/triumphstuff/spit80.htm
Punkin' - '78 Spitfire - in Superb Shape!
http://www.teglerizer.com/triumphstuff/spit78.htm
Lil' Greenee - '73 RWA Midget - finally home
http://www.teglerizer.com/midgetstuff/index.html
email: wizardz@toad.net http://www.teglerizer.com
-----Original Message-----
From: Justin Cook <justincook@yahoo.com>
To: spridgets@autox.team.net <spridgets@autox.team.net>
Date: Friday, November 19, 1999 11:22 AM
Subject: Re: Heater switch? -- Little LBC
I believe only AC current exhibits the skin effect
(traveling on the outside of the conductor). The
higher the frequency the greater the effect.
--- wizardz <wizardz@maxinter.net> wrote:
> An an electronics engineer with over 25 years in the
> field
> developing military field gear... believe me...
> that's what's used.
> when metal touches metal (spring loaded inside the
> switch)
> you get electrical contact. Period!
> The dielectric grease eliminates arching and
> sparking as
> the switch makes contact and keeps the 'elements'
> from
> deteriorating the contact surfaces.
>
> when you rub it around your spark plug boots... yes
> it's an insulator.
> You are trying to eliminate possible conduction
> pathes for electricity to
> follow. You're attempting to keep water and crud
> from creating a
> possible path for cvurrent to flow.
> Remember... electricity does not flow 'through the
> center' of a wire.
> It flows on the surface of the wire. Hence
> multi-strand wire of a small guage
> can carry higher amperage, (due to lower resistance
> -more surface area to conduct)
> than a single solid wire of comperable guage.
>
>
>
> Paul Tegler
> OBie - 1973 BGT - Daily Driver
> http://www.teglerizer.com/mgstuff/ob_description.htm
> Rat - 1980 Spitfire - fledgling recently left the
> nest
> http://www.teglerizer.com/triumphstuff/spit80.htm
> Punkin' - 1978 Spitfire - in Superb Shape!
> http://www.teglerizer.com/triumphstuff/spit78.htm
> Lil Greenee - 1973 Rnd Wheel Arch MG Midget in resto
> mode
> http://www.teglerizer.com/midgetstuff/index.html
> email: wizardz@toad.net
> http://www.teglerizer.com
>
>
> -----Original Message-----
> From: Chris Kotting <ckotting@iwaynet.net>
> To: spridgets@autox.team.net
> <spridgets@autox.team.net>
> Date: Thursday, November 18, 1999 1:21 PM
> Subject: Re: Heater switch?
>
>
> Excuse me, but why would you carefully clean a set
> of contacts, then put
> an >>insulator<< on them?
>
> Dielectric grease is NON-conductive.
>
> wizardz wrote:
> >
> > Don't sand or scrape clean metal electrical
> contacts.
> > Any small scratches just reduces the surface
> contact area leading to
> > more arching and less chance of getting a good low
> resisitance connection.
> > (let alone the future tarnish being buried down in
> the scratches where you can't get to it.
> >
> > Use a pencil eraser as the abrasive to clean all
> electrical contacts.
> > It's the equivalent of 3000 grit sandpaper and
> will leave a very bright shine on the metal
> > and makes it very easy to get down in the switch
> to clean them.
> > Just remember to clean out all the eraser shavings
> that rub off and
> > re-apply a nice coating of dielectric grease to
> keep them from tarnishing.
> > (the old dried out gunk in the switch when you
> took it apart is the old dried out
> > dielectric grease used when the switch was first
> assembled at the fatory)
> >
> > Paul Tegler
> > OBie - 1973 BGT - Daily Driver
> http://www.teglerizer.com/mgstuff/ob_description.htm
> > Rat - 1980 Spitfire - fledgling recently left the
> nest
> http://www.teglerizer.com/triumphstuff/spit80.htm
> > Punkin' - 1978 Spitfire - in Superb Shape!
> http://www.teglerizer.com/triumphstuff/spit78.htm
> > Lil Greenee - 1973 Rnd Wheel Arch MG Midget in
> resto mode
> http://www.teglerizer.com/midgetstuff/index.html
> > email: wizardz@toad.net
> http://www.teglerizer.com
> >
> > -----Original Message-----
> > From: Gerard Chateauvieux
> <pixelsmith@gerardsgarage.com>
> > To: Amy <casoich@sgi.net>;
> spridgets@autox.team.net <spridgets@autox.team.net>
> > Date: Thursday, November 18, 1999 1:40 AM
> > Subject: Re: Heater switch?
> >
> > Amy,
> >
> > These switches are pretty easy to open, you
> probably just need to clean the
> > contacts. There is a a small ball bearing and
> spring inside, so just make
> > sure you don't lose them when you pop it open. A
> point file or some fine
> > sandpaper will clean them up pretty quickly.
> Sometimes a little
> > vinegar/salt solution applied with a small brush
> will remove any corrosion
> > also.
> >
> > Gerard
> >
> > At 3:00 PM -0500 11/17/99, Amy wrote:
> > >Hi gang,
> > >
> > > I was wondering if anyone out there had an extra
> heater switch? When
> > >Les looked my car over, we noticed the heater
> wouldn't work. He bypassed
> > >the switch and tested the blower and it would
> spin then. Anyway, if
> > >anyone has an extra, please email me.
> > >
> > >thanks,
> > >
> > >Amy
> > >67 Sprite MkIV
> >
> > Artificial Intelligence is no match for Natural
> Stupidity.
> >
> > G G Gerard Chateauvieux
> > E A
> > R R pixelsmith@gerardsgarage.com
> > A A
> > R G Pixelsmith on Duty
> > D E
> > S http://www.gerardsgarage.com
>
>
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