coil confusion

From:  Thomas McGahee [SMTP:tom_mcgahee-at-sigmais-dot-com]
Sent:  Saturday, June 13, 1998 9:37 AM
To:  Tesla List
Subject:  Re: coil confusion

The technical difference between a Tesla coil and a
Oudin coil is simply that the base of the secondary
is directly tied to the primary in a Oudin coil,
whereas in a classic Tesla coil the base of the 
secondary is tied to a separate RF ground. It should
be noted that the Oudin coil connection reduces
stress between the primary and the secondary, but
is more dangerous.

Often a book or article will just refer to a coil
as a Tesla coil or a Oudin coil without really
implying any distinction between the two. For many
years the Tesla coil plans published in books and
magazine articles were actually showing a Oudin
style connection.

BTW, Odin and Oudin are two different spellings for the
same name. It is pronounced Wee-dah with a silent n.

A true Oudin coil Bipolar coil would have the
primary center-tapped and connected to the center of the
secondary. Note that a classic bipolar Tesla coil
would have absolutely NO connection between primary and
secondary. Such bipolar coils can easily become
imbalanced electrically if the discharge electrodes
on both sides are not identical in area. They can also
become imbalanced by any large object approaching
either terminal. The usual result is to have
arcs then jump from the center of the secondary to the 

A hybrid approach is to have two separate secondaries,
each with its own primary, but phased opposite. Note 
that this opposite phasing can be accomplished by
simply changing the phasing of the wiring to the
primaries. You do NOT have to wind the two primaries
or secondaries differently. You can if you want to,
but the only requirement is that SOMEHOW there is a
phase difference. Primaries can be in series or parallel,
but the series style connection seems more popular.
The base of each secondary is connected to a good RF ground.
The SAME RF ground. If you just interconnect the bases
of the secondaries and do not ground them, you are
asking for trouble!

Hope this helps.
Fr. Tom McGahee
> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-pupman-dot-com>
> Subject: coil confusion
> Date: Friday, June 12, 1998 11:21 PM
> ----------
> From:  Michael Tucknott [SMTP:Michael.Tucknott-at-virgin-dot-net]
> Sent:  Tuesday, May 05, 1998 7:20 AM
> To:  Tesla List
> Subject:  coil confusion
> Thank all.
> Yesterday I was after info now I`m just confused.
> So is a bi-pole one secondary and one primary or is it two secondarys
> back to back with two primarys in series and a discharge load at each
> end.
> What is the differance between a Bi-pole and an Odin coil.
> On another matter well done to Ed Sonderman on the success of his
> coil,can`t
> wait to see some pics of this bady.
> Cheers Mike Tucknott (UK coiler)