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Re: How to rise the secondary? (fwd)



---------- Forwarded message ----------
Date: Sat, 11 Jul 1998 00:47:27 -0500
From: "Barton B. Anderson" <mopar-at-uswest-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: How to rise the secondary? (fwd)

John,
I'm not sure I quite understand what your saying. First you say it's not
necessary to raise the secondary "if the TC is designed properly". Then you
finalyze by saying "I have not solved the problem of finding the exact coupling
for a particular TC". To me, these are two conflicting messages. For myself, I
(until I "can" calculate and build to the calculation exactly) choose to design
slightly over coupled so that I can "raise" the secondary to adjust coupling to
maximum capabilities without over-arcing. Maybe, you are playing devils-advocate
and asking how we can calculate to precision coupling?
Bart

Tesla List wrote:

> ---------- Forwarded message ----------
> Date: Fri, 10 Jul 1998 05:47:05 +0000
> From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: How to rise the secondary? (fwd)
>
>   To All -
>
>   Why are coilers building Tesla coils and raising the secondary to make
> them work properly? Raising the secondary of a properly designed and tuned
> coil only reduces the output. Why use a faulty design of excessive
> overcoupling then try to correct it by raising the secondary?
>
>   If a proper pri/sec clearance is maintained to prevent flashovers and the
> coil properly tuned raising the secondary is unnecessary. Tweaking is part
> of the tuning process and not necessary for coupling selection with a
> correct design. With a properly designed TC the quenching adjustments relate
> only to the primary circuit. Quenching always occurs after the first
> transfer when the secondary circuit has almost zero energy and has no effect
> on the primary circuit.
>
>   Critical coupling is the same for Tesla coils as it is for any dual
> coupled RCL system. If this condition can be determined at the time of
> design the correct amount of overcoupling can be determined and excess
> overcoupling avoided. It does not make engineering sense to deliberately and
> incorrectly design a coil with excessive overcoupling and then try to
> correct it by raising the secondary.
>
>   I have studied and researched this problem with over a dozen coils. My
> conclusion was that raising the secondary was not necessary with a properly
> designed TC. In fact a TC that requires raising the secondary can never be
> adjusted to produce optimum output. This is because moving the secondary
> away from the primary will reduce the output. I have not solved the problem
> of finding the exact coupling for a particular TC. However, coupling is not
> critical as it does not affect the amount of energy transferred. Only
> sufficient pri/sec clearance is required to prevent sparkovers. I agree more
> research is needed.
>
>   John Couture