Re: TC coil experements 7 years ago

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Finn Hammer <f-h@xxxx>

Gary,

Secondary inductance went from 9,96mH trough 21,54mH to 36,87mH
Your resonant frequency went from 289kHz trough 197,42kHz to  146,94kHz
Your primary inductance went from 28,5uH trough 65,3uH to 117,6uH

This means that your surge impedance went from:
53,38 ohms trough 80,8 ohms to 108,4 ohms
and your primary peak current (assuming 15000 volts on cap) went from
280A trough 185,6A to 138,3 A

What I am saying:

You did not take gap losses into consideration, and they might have 
been the cause of the difference in performance.

Cheers, Finn Hammer


Tesla list skrev:
> Original poster: gary350@xxxxxxxxxxxxx
> Vanderbelt University did some research on Tesla Coils.  The best 
> length to diameter ratio is 3 to 1 according to them.  Research 
> shows 3/1 is better than 4/1 and that is better than 5/1.  If you 
> are going for absolute maximum output try 3/1 ratio.
> I did some experenents with this myself and built 3 Tesla 
> Coils.  The 3 TCs are identical only thing that changes is the 
> secondary coil diameter to length ratio.
> TC #1, 950 turns #24 wire 20.5 inches in length wound on 4" PVC pipe.
> TC #2, 950 turns #24 wire 20.5 inches in length wound on 6" PVC pipe.
> TC #3, 950 turns #24 wire 20.5 inches in length wound on 8" PVC pipe.
> I used the same 15K 60ma neon sign transformer.
> I used the same .01 uf capacitor.
> I used the same VSVFSG spark gap.
> I used the same top load, toroid 14" diameter 4.5" thick.
> I built a flat would primary coil for each secondary coil.  The 
> inside turn of each primary was 2" from the secondary coil.  Primary 
> were all would with 1/4" copper tubing, flat wound, spacing 1/2" 
> center to center, 18 turns each.
> The only thing in the circuit that changed was the secondary 
> coil.  The primary coil physical shape had to accommodate the secondary coil.