Wire length,resonance, and Q (fwd)

From:  Mark S Graalman [SMTP:wb8jkr-at-juno-dot-com]
Sent:  Saturday, May 30, 1998 8:00 AM
To:  tesla-at-pupman-dot-com
Subject:  Re: Wire length,resonance, and Q (fwd)

  Terry and Greg,

 Perhaps if you check out my article in the TCBA
news it will be of interest:
An Analysis of a Tesla Coil
TCBA news Vol 12 #4 pages 14-16  1993

 Actually I think we're quite in agreement here,
but for a tesla secondary to be viewed as a
lumped inductor Cterm has to be VERY large in
comparison to Cself. But even under that
condition it is still a resonant transformer 
(narrowband response)

Mark Graalman

On Fri, 29 May 1998 23:22:42 -0500 Tesla List <tesla-at-pupman-dot-com> writes:
>From:  terryf-at-verinet-dot-com [SMTP:terryf-at-verinet-dot-com]
>Sent:  Friday, May 29, 1998 3:08 PM
>To:  Tesla List
>Subject:  Re: Wire length,resonance, and Q (fwd)
>Hi Greg,
>At 11:36 PM 5/28/98 -0500, you wrote:
>>From:  Greg Leyh [SMTP:lod-at-pacbell-dot-net]
>>Sent:  Thursday, May 28, 1998 7:17 AM
>>To:  Tesla List
>>Subject:  Re: Wire length,resonance, and Q (fwd)
>>Mark S Graalman wrote:
>>>   I have to wonder here if there isn't a simple
>>> misunderstanding of 1/4 wave resonance, the fact
>>> that we are talking about an ELECTRICAL 1/4 wave
>>> and not a PHYSICAL 1/4 wave. That a 'monopole'
>>> tesla secondary is a ELECTRICAL 1/4 wave from
>>> the bottom to the top, and any situation where one
>>> has a current node at one end and a voltage node
>>> at the other is being operated as a 1/4 wave electrically
>>> regardless of its physical length. 
>>This is true, and devices such as waveguide stubs and antennas
>>often operate in this 1/4 wave mode.  However, a TC secondary 
>>_does not_ behave in this way, for the following simple reason:
>>There is no actual voltage node (max V, min I) at the top.
>>Although there is a current node at the base (max I, min V),
>>the top winding carries both the maximum voltage _and_ nearly
>>the maximum current, just like in a standard HV transformer.
>My tests show that the all the current isn't making it to the top 
>I think the self-capacitance is storing energy and thus "stealing" 
>some of
>the current before it gets that high.
>>This current at the top simply goes into charging the top
>>electrode, which has a lumped capacitance back to ground.
>I agree 100%!!!  
>>The current going into the arc is typically only 30 to 40%
>>of the total current being delivered to the top electrode.
>>If you change the "electrical length" of the TC secondary, 
>>this will still be the case.
>        My recent paper describes a current test I did on my research 
>I found that the current going into the top electrode was about 60% of 
>current at the base (no breakout).  I found that this almost exactly 
>the ratio of top to self-capacitance in my system.  Do you (or any one 
>have any similar results that might add to this?
>        My results also show that the secondary was a lumped inductor 
>no standing wave effects.  Theory (the new one) suggests that the 
>phase was
>off by 0.1 degree but that is due to the propagation speed of light).  
>below my ability to measure.
>My early tests with arcs are still too early to comment much on.  I am
>building up new devices to measure this accurately.  However, the arcs 
>to be oscillatory high current pulses that drain the top terminal.  
>Cself may be harder to drain do to it's distribution on the secondary 
>inductance may get in the way). 
>Much to learn here.........
>        Terry Fritz