[TCML] Thumper, the worlds most advanced tesla coil.
mdt24 at case.edu
Mon Jun 7 22:03:24 MDT 2010
Looks excellent! For the predikter driver, did you just put a phase lead on
the current waveform prior to zero-crossing detection? Or did you do a more
sophisticated method, maybe with PLLs?
And how do you vary the tapping on the primary? Brush contacts?
On Mon, Jun 7, 2010 at 9:12 AM, Finn Hammer <f-h at c.dk> wrote:
> Thumper has finally found it's final form:
> (the little people gave a helping hand during the final stages)
> The first picture holds a lot of mythological significance to me. When I
> started coiling, a decade ago, I came across this picture:
> And I thought:"This can only happen in the States". Now, look at me
> standing next to Thumper.:-)
> Thumper is what I believe to be the worlds most advanced Tesla Coil ever
> The main feature of the coil started out to be the Predikter driver, which
> I posted about last year. This is the driver that predicts the primary
> current zero crossing, so as to initiate the switching of the bridge in
> advance of it, with the purpose of avoiding voltage transients. These
> transients occour because, if no measures are taken against it, the
> freewheling diodes will start to conduct and they will then be forced into
> reverse recovery when the bridge switches. This forced recovery shock
> excites the buss and creates a mess of high Q ringing. So it was a very
> valuable development there, and it has already become the standard of DRSSTC
> controllers used by the leading designers.
> This was developed with a less than desirable primary circuit, so a
> suitable design of this commenced.
> Since I invented the RAT technology some 8 years ago, I have wanted to
> apply it successfully. The original "Ambassador" coil was not a success due
> to my limited ability to controll the motors that position the variable
> In this latest version of the RAT technology, both coupling and Tapping
> can be adjusted *on the fly*. The motor controllers for these 2 function are
> 2 fiberoptic connected atmega 328 microprocessors. I am indebted to my
> adversary, fellow coiler and friend, Daniel Uhrenholt, for constructing
> these controllers.
> During first light, which happened last evening, we recorded this video,
> which to us, justified a year of work:
> It shows the primary current waveform, while we sweep the tapping point
> from 1/2 turn too low, and up to the sweet spot, where the notches appear.
> Notice that the current has dropped to half value by then, but the streamers
> have developed from 10 cm to 1 metre. With the notch in view, we then reduce
> the on-time till it coincides with the notch, and while this does not reduce
> the streamer, it reduces power consumption.
> We did not write down the voltages and currents because we wanted to watch
> the tuning from the artistic point of view. I built the coil to be able to
> watch the primary current on the scope, to get an intuitive understanding of
> the tuning.
> And Thumper payed back in silver dollars!
> The sweet spot occupies less than 5 cm on the primary, so we might well
> have missed it by manual tuning.
> Building this coil has beeen an unprecedented pleasure, so an abbreviation
> to describe it would not suffice, an acronym had to be pinned on it:
> I have setteled for this:
> Dual Resonant realtime Adjustable Solidstate Tesla Instrumentation Coil
> If this post have got you interested, a thorough documentation can be found
> on 4HV.ORG in the Projects board. Look for "Thumper"
> Cheers, Finn Hammer
> Tesla mailing list
> Tesla at pupman.com
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