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Re: Insulation on Primary windings (fwd)
---------- Forwarded message ----------
Date: Sat, 14 Feb 1998 08:59:56 -0500
From: Thomas McGahee <tom_mcgahee-at-sigmais-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Cc: Rodney.Davies-at-anu.edu.au
Subject: Re: Insulation on Primary windings (fwd)
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Insulation on Primary windings (fwd)
> Date: Friday, February 13, 1998 11:15 PM
>
>
>
> ---------- Forwarded message ----------
> Date: Sat, 14 Feb 1998 03:22:07 +1100 (EST)
> From: Rodney Graham Davies <Rodney.Davies-at-anu.edu.au>
> To: tesla-at-pupman-dot-com
> Subject: Insulation on Primary windings
>
> Hi All,
>
> Say, I'm designing a new small coil and am deciding on what type of
> conductor to use for the primary.
>
> I'm building a 3"x12" coil and am looking at a conductor diameter (for
> the primary) of 0.125". I could go for copper pipe, or I was thinking
> standard 30Amp Earth wire (which is about the same diameter).
>
> Refering to my subject line, Insulation on the primary, why is it, that
> for every coil I've seen (from miniature to huge), the primary windings
> *never* have any insulation... why is this so?
>
> Therefore, I was thinking that I might leave the insulation on the
> Earth wire that I'll use on the primary... good idea?
>
> Weird thought I know, rather trivial, but it's something I've not thought
> about before...
>
>
> Thanks!
>
> Catchya!
> Rod
Rod,
The main reason for no insulation is so that you can place your primary
tap anywhere you want.
Copper tubing comes bare. Trying to put a jacket on it is a real pain,
and actually does not really give you much useful in return.
1/4" tubing and 1/4" spacing works great for most coilers. The air
insulation between adjacent turns is both adequate and free. A nice
combination.
HOWEVER, if you are experimenting and just lashing something together
for a test, it is sometimes convenient to wind up a quick primary
from insulated wire. You would be surprised at how readily the HV
punches its way through insulation. Remember, we are working with
nasty pulsed RF. The IMPULSES are particularly good at puncturing
insulation!!
John Freau has wound several of his primaries close-wound using insulated
wire. Perhaps John might comment on his own experiences in this area.
You can surely use insulated wire for the primary. As a practical
matter, however, bare copper tubing with proper spacing as *the* way
to go.
Hope this helps.
Fr. Tom McGahee