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Re: RE- Secondary wire &
Subject: Re: RE- Secondary wire &
Date: Fri, 06 Jun 1997 20:28:00 GMT
From: robert.michaels-at-online.sme-dot-org (Robert Michaels)
Organization: Society of Manufacturing Engineers
To: tesla-at-pupman-dot-com
An (another!) fairly decent rebuttal post from Mr.
Skrocki (God, I hate those kind!). Many of the
points he makes are well taken (must he keep doing
that?!), but I'd like to offer up a precious-few
(I promise) counter-comments:
T> From: "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
T> To: Tesla List <tesla-at-pupman-dot-com>
T>oN Wed, 04 Jun 1997 08:07:00 GMT Robert Michaels
T><robert.michaels-at-online.sme-dot-org> WROTE;
T>> -- Making a space-wound coil using a closed loop (as a
T>> spacer) with a weight attached is effective, but I'd
T>> scarcely say it is "easily" done. In fact it
precludes
T>> any machine or power-driven winding of a coil.
T>Before I got my lathe I wound all my coils by hand and I never found
T>any difficulty in using a closed loop with a weight as a spacer, but
T>then I learned how to cut threads bare handed with a file so I guess
T>it's a matter of ones background.
I've never heard of using thread before your earlier post.
Interesting. What does it mean to "...cut threads bare
handed with a file..." ??? (also, ??!!?!!??, on second
thought).
[ ... ]
T>> In my experience, the closed, weighted loop is best
T>> made itself of magnet wire.
T>That I agree on! The best is to use the same wire your winding the
T>coil with. I also feel it's important to have a sticky base to wind
T>on so the spacing wont be for nil! I like thin double sided tape to
[ ... ]
BTW - It's possible to purchase bi-filar magnet
wire (and tri-filar for that matter): 2 (or 3)
parallel strands the entire length of the spool,
lightly stuck together (like the two conductors
of electrical lamp cord). I wonder -- might it
be possible to wind a coil with bi-filar wire
and then unwind one of the, er, ah, um, "filars"
to obtain a space-wound coil? Of course, it's
enamel-insulated magnet wire.
T>> -- In all but the highest powered Tesla coils, the
volts-per-
T>> turn of the secondary is apt to be below the
breakdown
T>> voltage of the wire enamel.
T>>
T>> Consider: A 500-Kv coil having a thousand turns
T>> in it's secondary (Love those round num-
T>> bers!). That's 500-volts/turn.
T>Huh! Accept for my very first coil (somewhat of a disapointment) I
T>NEVER use more than 600 turns on a secondary and of lately I a
T>getting better output with no more than 300 turns! This means my
T>coils would require a bit over 3 times the dialectric strength in the
T>wire insulation than your example.
T>> Which means, the wire enamel must withstand
T>> 250-volts. Not a major challenge for today's
T>> wire enamels. Comprendo, compadre -
250-v.?
T>In the comparasin to the coils I wind I would need over 1700 Volts of
T>insulation and I haven't found any enamel wire that holds up at that
[ ... ]
Point made and taken -- in the modern idiom of coils without
much coiling in them.
My principal point is:-- To consider turns-per-volts.
To remember that adjacent turns
are insulated by =two= layers
of enamel (or cotton) (or gutta-
percha).
I used 1000-turns only because it's a nice round number.
There are days when I hate the idea of having to divide
500 by 300 (The results of my calculations are apt to be odd-
enough as it is) (!).
BTW -- There are wire enamels spec'd to 600-volts/mil
(meaning it would tolerate 1200-volts/mil per
turn). Not a standard item you may be sure, but
not so rare a one either.
Also -- for the hi-buck boys -- or those lucky at love
or more particularly at scrap dealers -- Teflon-insulated
wire for aerospace use may be had. The Teflon can be
as thin as wire enamel. (The wire can be found silver-
plated as well {there's nothing quite like living
right} ) !
Gutta-percha, yesterday, today,
and tomorrow, in -- Detroit, USA
Robert Michaels