Re: Flat secondary measurements

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

Original poster: "Peter Lawrence by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>

Terry,

 >Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
 >
 >Hi Peter,
 >
 >At 11:26 AM 2/15/2002 -0800, you wrote:
 >>
 >>I'm thinking of building a TC with a flat secondary and helical primary.
 >>Sort of like a traditional TC turned upside down, but with lots of turns
 >>of thin wire in the flat secondary, and few turns of thick wire in the
 >>helical primary.
 >>
 >>This configuration should be as easy to model with etesla6/acmi/tssp as
 >>the traditional configuration.
 >
 >I assume this last sentence was meant as a question.  I "think" E-testla6
 >will allow for such a configuration.  If you try it and have trouble, let
 >me know and it would be easy to fix**.  I guess Paul is working on acmi and
 >TSSP.  I am sure there are going to be some problems along the way trying
 >to use are conventional math tools for this configuration but we should be
 >able to figure them out.


what I meant was that this is a simple geometric change that should require
only simple changes to the software (not require rewriting EM theory... :-)))

I am imagining two slightly different geometries though

a) upside-down TC - flat secondary has inner diameter about the same as
   the diameter of the helical primary, and they would be grounded together
   there (using a single ended OBIT to power the TC). The outer edge of the
   flat coil will be the high voltage end - place a toroid there.
   
b) the primary is helical but at the outer diameter of the flat secondary,
    so the secondary's inner diameter is quite small, and run a wire upwards
    perpendicular to the coil to a spherical topload.

The real problem with both of these is that the turn-to-turn voltage will
be much worse for a given overall size than with a traditional helical
secondary. My 12" high helical secondaries have 11" between top and bottom,
but a 12" diameter flat coil will only have ~5" between its inner and outer
windings. That is twice the volts-per-inch flat verses helical if you're
trying to get the same voltage from each (that may or may not be relevant
to spark length, which tends to be more dependant on bang size, but we wont
know what happens with flats until we try them...).


 >
 >** Oops!!  The secondary voltage profile will not work...  Hmmm...  A bit
 >of less than trivial change there.  I will look at it when I get a chance,
 >I have to go buy some parts to start building my flat secondary right now
 >   :-)))


Paul will have to work out the current/voltage profiles over the radial
dimension of the flat coil. Again I'm assuming this is a simple geometric
change from the existing ones and the software will be simple enough to
change.


>
>I though at least finding the wire length would be easy, but I see Jim's
>work is looking pretty complex (Make use of b^x = exp(x*ln(b)) so now you
>can integrate using integral( exp(ax) ) =1/a*exp(ax), where a=ln(b)...)  It
>"sounded" easy but...


WHAT???
   wire_length = number_of_turns * PI * (average_diameter, ie (ID+OD)/2)
DOH!!!



>
>Cheers,
 >
 >	Terry
 >
 >
 >
 >>
 >>-Peter Lawrence.
 >>
 >>
 >>>Perfectly fine to do just the flat secondary now to see where we are going.
 >>> When we get it all going and measurments start to come in, we can see
 >>>where to go from there.
 >>>
 >>>Cheers,
 >>>
 >>>	Terry
 >>>
 >>>
 >>
 >
 >
 
Enjoy,
-Peter Lawrence.