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Re: Help...I'm having a lot of problems here...

Hi Kent,
          I see a few things at first glance:

> Original Poster: "Kent & Kim Schaffer" <santoken-at-bright-dot-net> 
> 
> Hello all...
> 
> About six months ago my step son and I decided to build a TC for his science
> fair project.  Boy, was that a mistake...
> 
> First I'll tell you that this is my first coil project, so I'm sure we've
> made a lot of mistakes in our design.  I think that one of my biggest
> mistakes is that cap we are using (I thought I would try to save some time
> and money).
> 
> Power source:
> 
>     Furnace transformer or NST (I'm not sure):
>             -10KVA
>             -25 milliamp
> 
> Cap (set back for a good laugh):
> 
>             -12x    2KVDC .01 uf ceramic caps soldered  in parallel for a
> total of 24KVDC
>                 -submerged in mineral oil in plexi box

Hooking the caps in parallel doesn't alter the voltage rating at all. 
It remains that of the lowest voltage rated cap in the stack. What it 
does do is sum the capacitances. I'm guessing you've ended up with a
0.12uF capacitor rated at 2kVDC.
     Being limited to 25mA, the transformer is not going to charge a 
cap of that size to a very high voltage at all. Also, if you 
calculated your primary inductance to match the caps in series (i.e.
0.01uF/12 or 833pF), the coil will be way out of tune. Note also that
you will not get much energy at all from that capacitance charged to
10kV (or 14kV peak).
    I think you should aim to build a cap of about 6.6nF (0.0066uF)
for that transformer. Primary coil will need to be adjusted so the 
tank tunes to the secondary of course. 

> Spark gap (another joke): 
> 
>             -plexi box with three adjustable gaps in series
> 
> Primary:
> 
>             -3/8" copper tubing
>             -ID 7.7"
>             -Wire spacing ..875"
>             -5.5 total turns
>             -wound flat (0 degrees)
> 
> Secondary:
> 
>             -4.2" diameter (thin wall PVC drain pipe)
>             -21" long winding
>             -22 ga wire - enamel coated
>             -shellaced before and after winding
> 
> Toroid:
> 
>             -4" dryer duct
>             -12" diameter center of tube to center of tube
> 
> Now here is the problems we're having:
> 
> After hooking up the cap the way all the schematics show I get no discharge
> at the spark gap at all.  BTW, the way I read the schematics, one terminal
> of the cap attaches to the output of the transformer and the other attaches
> to the ground.  Now, if I attach the cap in a series (one terminal input,
> the other output) I get spark at the gap.
> 
> I have gotten absolutely no discharge at the torid whatsoever...sure does
> light a flourescent tube nicely though :-)

The radius of curvature is far too big for the amount of primary 
energy you are running. If you stick a metallic bump on it you should 
get something. However, get the primary capacitor and primary coil 
right first. 

Malcolm

> Does anyone have a suggestions...I'm sure some of you must!  Your response
> is greatly appreciated, since the science fair judging in Thursday...Yes,
> this Thursday.
> 
> Kent
> 
> 
>