Re: If correct, this will change everything!!

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

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

Hello Terry,
             A few comments about your paper:

- the notion of using high primary inductances to get primary
currents to a low level has been recognized as being beneficial for a
some time now. I did a quantitative analysis of this wrt spark gap
coils pre-1998.

- there is typo in the text; I'm sure 250mH using 1/4" Cu tubing is a
bit unrealistic for a coil that might be made transportable ;)  I
note that mH reverts to uH further along in the text.

- a 71 Ohm surge impedance is not terribly exceptional.

- the secondary losses are going to be rather high unless the coil is
physically huge in which case the associated capacitance is going to
be correspondingly high.

- You appear to be starting out with a charged primary capacitor
which rings down in conventional disruptive fashion. Have I
misinterpreted your scope shots?

I suspect you saw the same nirvana I did a few months ago at which
point I was reminded by a couple of list memebers that in the process
of ringing the system up, the double coupling artifacts do not allow
one to just ring up and up without intermediate energy trades.

(Aside - I realized why after considering that a conventional
disruptive coil has the same topology save that its "supply" is
effectively a zero Ohm piece of wire; both conditions are modelled as
being driven from voltage sources but in the old disruptive case, the
voltage source has zero output) - end aside.

The kind of analogue I had in mind was Dr Gary Johnson's coil which
actually took in the mS region to ring up to a useful level in that
fashion with a modest drive circuit.
       The results look far too good to be true - you have to pour a
considerable aomunt of energy into the secondary to get its voltage
to the point where you can generate some stretching (i.e. you are not
dealing with a drawn arc which to my mind is implied by the secondary
"load". Ideally, you want the secondary to ring up with as little
load as possible to get the output voltage high before letting go.
In short, I think the model is flawed.

Malcolm


On 3 Oct 2004, at 13:02, Tesla list wrote:

 > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
 >
 > Hi All,
 >
 > I was working on DRSSTC theory last night.  So I ran some models.
 > Slept on it...  Wrote it down this morning on the laptop...
 >
 > Just like the OLTC was optimized to giant low voltage currents, we can
 > optimize the DRSSTC to use small primary currents but higher voltages.
 >  Then we can take advantage of the fact they have vast power reserves
 > unlike a cap discharge coil that only has a fixed amount of bang
 > energy.  Then we can optimize it all to run off "little cheap"
 > IGBTs...  This all went pretty quick, but unless I messed up, the
 > whole world of coiling will change now...
 >
 > http://hot-streamer-dot-com/temp/DRSSTC-Optimization.pdf
 >
 > http://hot-streamer-dot-com/temp/DRSSTC.sch
 >
 > Of course, if I made some giant boo boo, forget I ever brought it up
 > ;-))
 >
 > Cheers,
 >
 >  Terry
 >
 >
 >