Wire length,resonance, and Q (fwd)
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)
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 electrode.
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 coil.
I found that the current going into the top electrode was about 60% of the
current at the base (no breakout). I found that this almost exactly matched
the ratio of top to self-capacitance in my system. Do you (or any one else)
have any similar results that might add to this?
My results also show that the secondary was a lumped inductor with
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). Far
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 seem
to be oscillatory high current pulses that drain the top terminal. The
Cself may be harder to drain do to it's distribution on the secondary (the
inductance may get in the way).
Much to learn here.........