Re: Three coils DRSSTC

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

Hi Liviu,
            My second working Tesla coil was built exactly like the
one described below (except that it was disruptive). The extra tank
circuit was built on a cardboard former the same diameter as the
single turn primary, Tesla-style and was tuned using a ceramic
transmitter cap (which succumbed to the stress after several years).
The reason I did it was to get around the abysmal Q of the primary
which was pegged by the secondary design which obviously couldn't be
altered. The scheme worked very well but the overall result was still
pathetic compared with the later results I got from the same
transformer and a half-decent coil design (5 feet as opposed to 20 or
so inches).
      According to the CSN, Tesla spent some time investigating this
configuration. My take on its operation with regard to my coil at the
time was that it boosted k between the primary and secondary
considerably. That may not have been the whole story since the
configuration is roughly equivalent to a standard magnifier and
therefore had more resonance modes present.

Malcolm

On 27 Sep 2004, at 11:13, Tesla list wrote:

 > Original poster: "Liviu Vasiliu" <teslina-at-yahoo-dot-com>
 >
 > Hi
 > Sometime ago, on tesla list, we discussed about some
 > special HV transformers with 3 windings (primary,
 > secondary and a third coil which forms a resonant
 > circuit with a cap connected to its ends). This made
 > me think if this approach would not be usefull in a
 > dual resonant coil. The benefits would be:
 >
 > - free ringing at low resistence in the resonant
 > circuit, feeding the streamer with more energy, after
 > the primary (driven by an interrupted SSTC) stops
 > conducting.
 >
 > - overcurrent protection for the bridge components,
 > which would not be stressed by the high currents
 > circulating in the resonant winding.
 >
 > So, I built a messy prototype TC which gave some good
 > results ( +40% spark lenght increase with the resonant
 > coil versus simply interrupted SSTC).
 >
 > The schematics and pics are here:
 >
 > http://www.geocities-dot-com/teslina/3cdrsstc.html
 >
 > The project was a result of the "necessity" because
 > the high current IGBTs dont live on this land..
 > Maibe this approach is a way to go..
 >
 > teslina
 >
 >
 >
 >