Re: Why isn't it working

["Malcolm Watts" <malcolm.watts-at-wnp.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Jeremiah,
                     Sounds like a tuning problem or too little energy to 
allow the top to break out to me so let's see:

On 7 Jun 00, at 8:05, Tesla List wrote:

> Original Poster: "Jeremiah" <jmeizis-at-metallicafan-dot-com> 
> 
> I have hooked up my coil a few times now and their is nothing.  No corona
> no sparks except for the spark gap.  I flip the switch and nothing happens
> except my mom complains about T.V. interference.  Please help.  Here is som
> specs of my coil.
> 
> Static spark gap: 5 copper pipes each .03 mm apart.
> 
> Capacitor: Saltwater bottle caps.  4 glass 2 plastic.  Total capacitance of
> .00432.
> 
> Secondary Coil Design
> 
> Diameter of secondary coil : 40.00mm
> Winding height of secondary coil : 140.00mm
> Wire diameter for secondary coil : 0.20mm
> Spacing between windings : 0.00mm
> Secondary turns : 699.00
> Secondary wire length : 87.84m
> Secondary inductance : 4.87mH
> Approximate resonant frequency : 1371.58kHz
> Secondary quarter wavelength resonant frequency : 853.84kHz
> Secondary self capacitance : 2.76pF
> Toroid capacitance required to form quarter wavelength coil : 4.37pF

A comment FWIW - the frequency the secondary resonates at *is* 
the 1/4 wave frequency. The relationship between wirelength and 
frequency is rather weak at best.

     A key piece of information is missing: what is the resonant 
frequency of the coil with the topload fitted - or isn't there one?

> 
> Primary Winding Design
> 
> Primary resonant frequency : 853.84kHz
> Secondary coil diameter : 40.00mm
> Primary conductor diameter : 6.00mm
> Primary turn to turn spacing : 10.00mm
> Spacing between the secondary and the inside turn of the primary : 10.00mm
> 
> The primary will need to be tapped between turn 6 and turn 7 to form a
> resonant circuit at  853.84kHz
> 
> The approximate inductance at each turn is : 
> 
>  Turn  1           0.13uH
>  Turn  2           0.46uH
>  Turn  3           1.05uH
>  Turn  4           1.95uH
>  Turn  5           3.22uH
>  Turn  6           4.94uH
>  Turn  7           7.15uH
>  Turn  8           9.93uH
>  
> Neon Transformer 
> 
> Transformer secondary voltage : 12kV
> Transformer secondary current : 30mA
> Number of transformers : 1


Based on Cp = 4.32nF  (that value is only 2/3 of the capacitance to 
resonate with the transformer BTW) and assuming the gap would be 
set so that the cap voltage could reach about 17kV (about 
Vrms*SQRT2) you would have 624mJ available per bang which 
sounds good for that coil. However I see the total gap is only .12mm.
Correct?  If so, it is set much too narrow. Try a couple of mm.

Regards,
Malcolm