Re: [TCML] DRSSTC tuning at high power

[Finn Hammer <f-h@xxxx>]

Michael

A lot of unknown factors have been mentioned as reason for your coils
relative lack of performance, you mention tuning yourself, and I think
the problem lies there:

You don't have a tuning problem, you have a design problem.
As I see it, the 4 rings with which you attempt to represent a sphere is
only what they look like: 4 rings. The toroid has for decades been the
standard for toploads, and you should get one before anything else.
Daniel Uhrenholt and Myself built coils that can be tuned in real time,
to investigate tuning points better. We are both toolmakers, so we can
make these things, and we are not the methodical types that go back and
forth a zillion times to adjust tapping points.
With the RAT (Realtime Adjustable Teslacoils) coils, we can watch the
effect on the primary waveform, while tuning the primary in one
uninterrupted sweep.
On the "Thumper" coil, where there are 4 primary turns, the notch only
appears when tuning within approx 10cm of the primary. It is a very
narrow window, and I know we had probably never found it without the RAT
coil.
But once dialled in, we can increase power and decrease the primary
frequency accordingly, and keep the notch!
So, to answer your question, yes, your waveforms look allright, but you
have not yet found the sacred notch.

Cheers, Finn Hammer



----- Original meddelelse -----

> Fra: Michael Twieg <mdt24@xxxxxxxx>Til: Tesla Coil Mailing List
> <tesla@xxxxxxxxxx>
> Dato: Fre, 20. maj 2011 17:08
> Emne: Re: [TCML] DRSSTC tuning at high power
> 
> found some primary current waveforms I had taken recently. They're
> all for
> the same tuning configuration, but at different repetition rates.
> At 208Hz: http://imgur.com/TpjEY
> at 330Hz: http://imgur.com/R9ieE
> at 523Hz: http://imgur.com/pMq2j
> Scale is 200A/V or 400A/div
> You can see how the notch is barely there to begin with at 208Hz, and
> at the
> PRF gets higher it disappears and the peak Ip grows greatly. The
> first
> 270us of the waveform is being driven by the H bridge, the rest is
> just
> freewheeling. I can't tell if the power in the secondary is being
> recovered
> or not...
> 
> Do these waveforms look reasonable?
> 
> -Mike
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