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Oudin Coil vs Tesla Coil




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From:  Antonio C. M. de Queiroz [SMTP:acmq-at-compuland-dot-com.br]
Sent:  Thursday, March 19, 1998 11:03 PM
To:  Tesla List
Subject:  Re: Oudin Coil vs Tesla Coil

Thomas McGahee wrote:

> Sorry, but the above explanation is not entirely correct. True,
> the Kick Coil itself is indeed a form of self-induction coil.
> Its purpose is to step the 110 volts up to several hundred volts.
> When the Kick Coil pulls in the interrupter there is a fairly
> large peak voltage produced, and this is stored in the capacitor.
> When the interrupter re-connects, it connects the CHARGED capacitor
> to the primary in such a way that it now forms a classic resonant
> circuit. BTW, the official name for that secondary thing is
> "the Resonator". Sound familiar?

Ok. I see now how a Tesla coil behavior is possible:
With the input voltage applied (AC or DC), the current flowing through
the kick coil and the primary coil increases at a rate limited by the
inductance of the kick coil (the capacitor is practically short-circuited
by the primary coil).
At some point, the vibrator is attracted, opening the circuit.
At this point there is a pulse at the output, due to the energy stored
in the primary coil being transferred to the secondary coil (induction
coil effect).
The current in the kick coil must go somewhere, and charges the 1 uF
capacitor to high voltage.
In this process, the current through the kick coil drops, and the
vibrator is released.
The vibrator connects the charged capacitor to the primary coil, and
then a Tesla coil behavior is possible, with adequate tuning.
Note that there is no trapping of energy in the secondary, but the
generation of high voltage by double resonance works in the same
way.
The (slow) recharging of the kick coil starts again at the same time.

> The inclusion of the rheostat by Mr. Harry D. Simons was a mistake on
> his part, and when I visited with him in 1965 I pointed out that fact
> to him. He included it simply because he found that it gave him a small
> degree of control over the output. Hey, what works, works!

I Agree now. Thanks for the observation and other interesting comments.

Antonio Carlos M. de Queiroz
http://www.coe.ufrj.br/~acmq