RE: How to rise the secondary? (fwd)

---------- Forwarded message ----------
Date: Mon, 13 Jul 1998 07:20:23 -0400
From: "Thornton, Russ #CSR2000" <ThorntoR-at-rc.pafb.af.mil>
To: 'Tesla discussion Group' <tesla-at-pupman-dot-com>
Subject: RE: How to rise the secondary? (fwd)

I agree with your statement about the poor engineering practices of
building adjustments into a system when proper design would make it
superfluous.  However, you are implying that there is an algorithm for
building the coils to make the required coupling.  I have collected and
categorized quite a bit of data over the past few years that I have been
reading from you and the other gurus on the list and after a search of
the coupling section I am at a loss.  I have found only how to define
and measure the coupling factors but not  anything on how to build to
the critical coupling.  Could you please illuminate it for me(us).

Russ Thornton
CSR 2040, 
Building 989, Rm.  A1-N20
Phone: (407) 494-6430 
Email: thorntor-at-rc.pafb.af.mil

>From: 	Tesla List[SMTP:tesla-at-pupman-dot-com]
>Sent: 	Saturday, July 11, 1998 12:23 AM
>To: 	tesla-at-pupman-dot-com
>Subject: 	Re: How to rise the secondary? (fwd)
>---------- 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