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

Hello Kent,

Let me see if I can help you out. My comments are interspread below.

>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).


Well, there is nothing wrong with trying to save money. Since this is
your first coil you will be bound to make mistakes. Every coiler
started out small and made mistakes. Mistakes are good because
they help you learn.

>Power source:
>    Furnace transformer or NST (I'm not sure):
>            -10KVA
>            -25 milliamp

Okay.

>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


Now, here is a problem. If you really wired them in PARALLEL,
they are probably dead, because the cap voltage will still be the same
(2kVdc) as a single cap. On the other hand if you meant series, you
will arrive at a cap with only 830 pF (10nf/12 pieces). This wonīt get
you any sparks because the energy stored in your caps is only 0.083J.
For your 10kV xformer I would suggest using at LEAST 8nF (which is
about 10x as much capacitance as you have now). DC ceramic caps
arenīt the best for TC usage, but if you keep run times short, they
should be okay They might be pretty lossy,tho.


>
>Spark gap (another joke):
>
>            -plexi box with three adjustable gaps in series


While a 3 gap spark gap might not lead to the best sparks, it should
work. You might want to go for more gaps in series. Something like
6-9 minimum would be better

>
>Primary:
>
>            -3/8" copper tubing
>            -ID 7.7"
>            -Wire spacing ..875"
>            -5.5 total turns
>            -wound flat (0 degrees)


Sounds okay. A flat primary might be giving you too little coupling
(looking at your input VA here).  You might want to turn this into a
cone coil. All you need to do is change the supports (30-45°
angle). You wonīt need to rewind it, however.

>Secondary:
>
>            -4.2" diameter (thin wall PVC drain pipe)
>            -21" long winding
>            -22 ga wire - enamel coated
>            -shellaced before and after winding
>

Sounds okay.

>Toroid:
>
>            -4" dryer duct
>            -12" diameter center of tube to center of tube
>


This might be slightly too big, but should work.

>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.


No, this is incorrect. The spark gap goes across your xformer
(in parallel). One lead of the xformer goes directly to your
primary. The other goes to the cap. The remaining cap
lead is connected to the second primary lead.

How are you grounding your secondary?

There should be no connection between primary and secondary.

Also, no part of the primary tank circuit should be grounded.


>is greatly appreciated, since the science fair judging in
Thursday...Yes,
>this Thursday.

I think your main problems are:


a.) The hook up
b.) Your primary cap size

Try start looking there and good luck on beating that deadline.


Coiler greets from germany,
Reinhard