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Re: Racing Spark Prediction



Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Dmitry,

So the lower two thirds of the coil is normal and the top 1/3 is reverse wound...

The current is less at the top of the coil but there would be some reverse voltage in that case... If we assume a linear voltage profile with maximum voltage per turn at the base and practically 0 at the top and we fold the top third...

Thinking.... #%&:-p  Integrating  |\:-p   ....

So if the total normal voltage is 1, the total voltage across any part of the coil starting at the base is X and assuming a height of 1:

Vt = 2 x (X - X^2 / 2)

If we put in 2/3 for x we get 88.9% of the voltage still at the top!!!! :-))))) That is not a significant hit if it stops the racing arcs and allows tighter coupling!!! The DRSSTC folks really like high coupling so this might be very useful to them!!!!

Note that the top third might be somewhat shorted by the top terminal which is basically a lossy shorted turn.... Just to make it more messy %:o)

Cheers,

        Terry





At 11:00 AM 5/17/2006, you wrote:
folded resonator as one of the possible cures from racing sparks

Paul wrote: nothing

ok, Paul - i ask you here (to screen poss mail problems) third time -
what is the problem with a folded resonator concept? this would be my
last question to you at all if not answered. you give me no choice : )

Terry wrote:

> I think the problem is when you reverse wind part of the coil, the
> performance would also drop way down.  You can get ride of any
> harmonics by making the coil out of dirt too but that is no fun.

i can`t see how it can be a problem - you`ll lose a very small part of
total sec inductance only, since mutual inductance between parts is
very small, as well as mutual/coupling between pri & reversed part of
the secondary.