Re: Twin SSTC (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 7 Jul 2007 18:03:18 -0500
From: D.C. Cox <resonance@xxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Twin SSTC (fwd)



Running a "random" IC circuit in front of each IGBT driver might cure these 
problems.  The triggering would randomly trigger at a random triggering 
cycles of perhaps 2,000 per second.  This would insure there would always be 
a point every portion of a second (or perhaps shorter time period) in which 
they would not be locked into a pattern where one is active and one is 
dormant (as described in your posting).


Resonance Research Corp.
www.resonanceresearch.com


----- Original Message ----- 
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Saturday, July 07, 2007 12:31 PM
Subject: Re: Twin SSTC (fwd)


>
> ---------- Forwarded message ----------
> Date: Sat, 07 Jul 2007 10:19:32 -0800
> From: Greg Leyh <lod@xxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Twin SSTC (fwd)
>
> Hi Steve,
>
> The NLL twin prototype coils use a classic Tesla Coil primary circuit,
> with an inductor, capacitor and a switch.  There are no master
> oscillators, or any type of feedback system as used in DRSSTC designs.
> The switch is a single IGBT, which receives an ON signal for the
> duration of the 1st envelope (exactly 2 cycles in this case.)
>
> Later on, during the secondary ringdown and after the main arc activity
> trails off, the primary switch is turned ON again, to recover the energy
> remaining in the secondary.  The timing and duration of this action is
> not critical.  It appears that up to 5-25% of the energy can be
> recovered using this method.
>
> The design of the NLL twin prototype coils attempts to incorporate and
> test every feature that might be used with the final NLL 120ft coils,
> including aspect ratios, coupling, primary drive topology and energy
> recovery.  The design is necessarily as simple as possible, in order to
> scale to the final size with minimal risk.
>
> Yes, each tower must have it's own independent drive system, as a 600ft
> round-trip xmsn line operating at 50,000A pk would not be practical.
> The phasing between the two coils is then adjusted by setting the time
> delay between the two envelope command signals.
>
> So far, we've had just two opportunities to run the coils; at the Maker
> Faire and the Integratron.  The coils displayed a wealth of unexpected
> and unexplainable behavior, particularly in terms of how the two
> secondaries interacted and coupled with each other.
>
> For instance I had originally assumed that the streamers would repel if
> the two coils were in phase, and attract when the coils were 180deg out
> of phase.  Observed behavior at Maker Faire was completely different.
> The arcs would bridge as expected at 180deg, but adjusting the phase in
> either direction would cause one streamer to *grow* in length while the
> other streamer would almost disappear!  The first 10 seconds of this
> YouTube clip shows this effect, as I run the phasing from 0, thru 180 to
> 360, and back:  http://www.youtube.com/watch?v=06hWFQSqJfI
>
> Scope waveforms of both coils' Isec indicated that the phase was indeed
> changing, and that the Isec amplitudes were remaining relatively
> constant.  However, Ansoft Simplorer simulations indicate that
> substantial energy can couple between the secondaries through the
> toroid-toroid capacitance.  In the simulation, a mere 6pF (my rough
> estimate for the actual Ctor-tor) will couple nearly all the energy from
> one sec to the other in about 8 cycles.  I plan to make a more refined
> measurement of the secondary interactions when the San Francisco lab is
> set up later this month.
>
> One other odd bit of behavior occurred when the phasing was set around
> 180, and the primary voltage was decreased so that the streamers barely
> touched.  One could see the interaction point physically move several
> feet back and forth between the coils, at a speed of about 1-2 Hz.  This
> movement was strongly reflected in the Isec waveforms, in the form of
> their *Fres* alternately changing, at this 1-2 Hz rate!  That is, the
> start of both Isec waveforms remain locked in phase, but about 6 cycles
> into the envelope the relative phases are shifting past each other by
> over 90 deg, at this 1-2 Hz rate.  I don't have any footage of this
> effect, but it's fairly easy to replicate, and  plan to do so as well
> when the labspace is ready.  My only theory at this point is arc loading
> of Fres.   GL
>
>
> Tesla list wrote:
>> ---------- Forwarded message ----------
>> Date: Fri, 6 Jul 2007 11:52:04 -0600
>> From: S&JY <youngs@xxxxxxxxx>
>> To: Tesla List <tesla@xxxxxxxxxx>
>> Subject: Twin SSTC
>>
>> Greg Leyh recently demonstrated his large twin SSTC at the Make Fair, or
>> whatever it was called.  What was unique was that it was really two
>> phase-locked SSTCs, each with its own power driver.  This allowed
>> elimination of a transmission line to connect the two primaries in 
>> series.
>> Instead, I presume he controlled the drivers with a pair of fiber optic
>> links from a master oscillator in his control box.  He also had the 
>> ability
>> to vary the phase relationship between the two coils, which could make 
>> for
>> interesting effects.  His power drivers apparently are something beyond
>> DRSSTCs in that they can redirect unused energy back into the power 
>> supply
>> or supplies for better efficiency (I don't know if he uses a common power
>> supply, or one for each coil - I suspect the latter).
>>
>>
>>
>> I would love to know more details.  My question is, would Greg or anyone
>> else knowing more details about Greg's setup be willing to share them 
>> with
>> others?
>>
>>
>>
>> Also, has anyone else built a twin DRSSTC setup using separate drivers 
>> for
>> each coil?  If so, would you please post some details?
>>
>>
>>
>> Finally, I believe a twin TC driven with two SISGs, each triggered with 
>> the
>> same pulse ala Finn Hammer style, wouldn't work well because there would 
>> be
>> no way to phase lock the frequencies of the two coils.  Is that correct?
>> Or, if the resonant frequencies of the two coils were almost identical,
>> would they lock in phase via the streamer connecting the two toroids?
>>
>>
>>
>> All comments will be appreciated.
>>
>>
>>
>> Thanks,
>>
>> --Steve Y.
>>
>
>
>
>