Re: Primary Question

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Dave,

The flat sprial primary will be perfectly fine.  

I would guess the old Ford coil is 20 -30kV.  Mine are too old to power up but
they probably put out about 1/2 to 3/4 inch sparks.

BTW - Very nice coil!!

Cheers,

        Terry


At 07:58 AM 2/13/2002 -0600, you wrote: 

>
> Hi All,
>
>  
>
> After seeing my 1.35KVA Tesla coil in action, my son is interested in a
> smaller scale model for a school science project. Never needing an excuse to
> make sparks I immediately agreed and started working on a design with him. It
> is also a great opportunity to use up a number of the spare parts I have
> floating about my shop. 
>
>  
>
> Obviously this needs to be very low power so for safely considerations I am
> going to make it battery operated. For power I plan to use an old
> reproduction model T spark coil my mother bought for me at Pep Boys around
> 1968 (she thought my strange hobbies a safer alternative to drugs). The
> secondary will be 3.25 inches diameter thin wall PVC with 18 inches of 26
> gauge wire (~1000 turns). For the tank I acquired some very nice small pulse
> caps (value as used .0125 -at- 40KV) with the help of someone from this list. It
> will use a simple static spark gap with some left over tungsten rods from my
> SRSG. I have a beautiful little 6 inch spun aluminum toroid I bought from a
> member of this list for the final.
>
>  
>
> My question concerns the primary and what shape to use. Ease of construction
> would suggest a vertically wound concentric primary. Alternately we could
> build a 30 degree cone or the now popular flat spiral. What are your
> experiences with these primary shapes in small, low power coils? What is the
> most efficient choice for best output?
>
>  
>
> Also while I have your attention does anyone know the approximate value of
> the high voltage one normally sees from a model T coil when run at 12 volts
> (current draw is about 1.5 Amps and it makes a pretty healthy spark)? 
>
>  
>
> Thanks for your help,
>
> Dave
>
>  
>
>
> <http://home.austin.rr-dot-com/dkyle/tesla.htm>http://home.austin.rr-dot-com/dkyle
> /tesla.htm
>
>  
>
> =========================================
> Dave Kyle
> Austin, TX USA
> Email: dave-at-kyleusa-dot-com
>
>