Re: Model T First Light - Take Two

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Dave,

Congrats on getting the Model T running! Your coil is a nice setup and can
obviously handle a
whole lot more than your giving it. I guess now you will be looking to
increase that spark
length. Without change of power supply, I'd suggest double up on the
capacitance and see if the
supply can charge it (I assume that would be a matter of reconfiguring the
caps for 40kV,
2000pF). Other than that, I'd say try another current source. Just some
thoughts, I know you
may just want to play around with it the way it is right now.

Take care,
Bart

Tesla list wrote:

> Original poster: "David Kyle by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<dave-at-kyleusa-dot-com>
>
> I completed the redesign of the Model T Spark Coil powered Mini-coil and
> achieved first light. I measured a 1.25 inch spark which admittedly is
> pretty puny but when you take into account that it is powered from a
> battery powered Model T spark coil this really is not too bad. No
> breakout but placing a sharp point on the toroid will yield a 1/4 inch
> discharge. No doubt far greater output would result with more input
> current.
>
> Specs are as follows:
>
> - 12 volt sealed gel cell battery power source
> - Pep Boys reproduction spark coil from 1968 (my mother bought it for
> me)
> - Thoriated Tungsten spark gap set to slightly over a 1/16 of an inch
> - 12 inch helical primary wound with 1/8 copper tubing, tapped at turn
> 20
> - 2 x 2000pf doorknob caps at 40KVDC in series for a total of 1000pf at
> 80KVDC
> - 18 inch secondary wound with 1000 turns of 26 gauge wire on 3.25 inch
> thin wall PVC tubing
> - 6 inch spun aluminum toroid
> - Current draw is slightly less than 2A at 12VDC
> - Calculated resonant frequency is 421KHz
>
> Tuning was a breeze as it came up exactly as predicted by JavaTC. Being
> very low power permits some interesting investigations since it is
> possible to map out the field of the coil with a small neon tube with
> out fear of electrocution. Fluorescent tubes easily light up about 18
> inches from the coil. The coil operates fine without a ground reference
> and the discharge slightly decreased when a ground reference was
> connected.
>
> I am very grateful to the assistance that this list provided. This coil
> is your success as well.
>
> It is worth noting that I learned far more from the failure of my first
> attempt with the mini-coil than in my previous successes with my big
> coil. Failure is a great teacher if you are willing to listen.
>
> Pictures can be found at the bottom of the following page:
> http://home.austin.rr-dot-com/dkyle/tesla_gallery.htm
>
> =========================================
> Dave Kyle
> Austin, TX USA
> Email: dave-at-kyleusa-dot-com