Re: Requesting help with construction of coil

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Harold Weiss" <hweiss@xxxxxxxxxx>

Hi Christopher,

Sounds like too much coupling.  Raise the secondary up to where you get no
racing sparks and run thru your tap points again.  Also put a breakout point
on the toroid while tunning.  The 19x4" toroid seems a bit on the large side
for a 3" coil.  Currently it appears you are "force driving" the coil and
not operating at true resonance, that's why the tap point makes no
differance.

David E Weiss

> Original poster: "Christopher" <cpfortun@xxxxxxxxxx>
>
> Hi,
>
> I'm writing in regards to a new coil I recently constructed. The specs are
> as follows : 9kv franceformer....180mA, SRSG, a total of 24 caps.....8
> seriesed 3 legs paralled.. (.15MFD at 2000V each) making for a total of
> .058MFD, the primary coil consists of 11 turns......the first four turns
> are vertical and the other seven are horizontal.....I am using 1/4" soft
> copper tubing "OD" and the spacing between the turns is 1/4", the
secondary
> is 3" "OD" with a total height of 24 1/2" with the magnet wire wrap length
> meausuring 22 3/4"........on top of the secondary is a spacer which holds
> the toroid a total of 3 1/2" above the secondary, the toroid measures 19
> 1/2" by 4". The electrical connections are as follows : xfmr is in
parallel
> with the caps, on end of the caps is connected straight into the primary
> coil, the other end of the caps is connected to the spark gap (one side of
> the spark gap), the other side of the spark gap is used for the tapping
> point of the primary coil, (The safety gap, secondary coil, and strike
rail
> are connected together as one source going to RF ground). If there may be
> any questions that need further explaination in regards to the mechanical
> or electrical setup let me know.
> Moving on to my troubles.......when I initially constructed my coil I
> allowed for a 5" inside diameter between my secondary and
> primary........which left a total of 1" spacing between these two. This
> wasn't enough because I was getting sparks from my primary to my secondary
> on the vertical turns. So I redid my primary and made for a 6" inside
> diameter needless to say this fixed the problem and decreased the tapping
> point. The problem now is that my streamers are extremely short, maybe 10
> inches, and I am getting sparks that start about the middle of my
secondary
> which strike down to my primary. The tapping point has no effect on the
> size of the streamers no matter where I tap it, they are the same l ength.
> I tried raising the secondary gradually but has no effect on eliminating
> the sparks from the secondary to the primary.....I either get sparks or
> nothing at all. The spark gap is set up as 4 stationary electrodes and 1
> rotating electrode. I am also using a variac with this system. After the
> spark gap has been turned on and operated up to full speed, I slowly turn
> up the variac from 0 V to 120 V, this is the reaction of the spark
> gap....all four will fire, then two will fire and them the other two will
> fire almost instantaneously, then only two of the electrodes will fire
> until I reach 80 volts and then all four will kick in again and stay on up
> to 120 volts. Does this sound pretty normal for the operation of it ?
> Anyhow that's enough for now.
> Any feedback in regards to the sparks from the secondary to the primary
and
> just the overall setup and operation of this unit will be greatly
> appreciated :)
> Thanks,
> Chris F.
> <mailto:cpfortun@xxxxxxxxxx>cpfortu n@xxxxxxxxxx
>
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