Re: It lives!!!!!

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Dirk,

Sounds like all is going very well!

You should try (if you have not already) moving 
the primary tap point around to fine tune the 
coil.  Just try tape points around where you are 
at now  (like +-2 turns in 1/4 turn steps) until you get the best sparks.

A 15/30 NST is 450VA "officially", but it can run 
at up to 8 amps in our case.  The charts below puts it at about 800VA:

http://hot-streamer.com/TeslaCoils/Misc/NSTStudy/NSTStudy.htm

so 800/120 = 6.66 amps (Halloween >;-)).  BTW - 
there is a lot of great info in this long forgotten link!!

Turn on transients and such can push the current 
a little higher so use like 8 amp slow blow 
fuses.  At 140 volts input, maybe make that 10 
amps.  I always like fusing neutral too...  Real 
good in odd situations where the AC power is 
pretty freaky...  I would not be surprised if the 
neutral was carry a bit more current that the 
line.  Maybe a clamp meter to see??  Power factor 
correction caps 140uF "motor run" would almost cut the line current in half!

If your primary is real close to the floor or any 
other big object that can absorb magnetic energy, 
that may steal power from your coil.  I know it 
is a big problem with my little coil on concrete floors.

http://hot-streamer.com/TeslaCoils/MyCoils/SmallCoil/s-small_coil2.jpg

I always have to put that coil up on a box or something to get good output....

I think these tips will improve things a lot.  I 
think rewinding with #28 wire or using an MMC 
will "not" get you much better performance in 
your case unless the doorknob caps are getting obviously hot.

Cheers,

        Terry




At 01:12 PM 10/31/2005, you wrote:
> Well after 3 months, I finally finished my 
> coil.  I would like to thank everyone on this 
> list with a special thanks out to Terry Fritz, 
> Dr. Resonance, Rich from Missouri, Jim L., Gerry R. and Tedd P.
>
> My father and I are both IBEW(LU#124) 
> electricians but this was quite a learning 
> experience for the both of us. While we both 
> went through the apprenticeship at the hall and 
> touched on theories such as  high voltage, we 
> rarely used this knowledge. For example in my 12 
> years in the field, I have never had to size a 
> capacitor besides in class. Most of the time 
> things are already spec?ed out and we tend to be merely installers.
>
>
> Anyway, here are the specs to my TC:
>
> Power supply ? 15/30 NST
> Secondary - 22? x 4? - #23 AWG
> Primary - Flat about 14 turns - ½? spacing. ¼? 
> copper tubing was tapped at 13 turn
> Capacitor - .008 uF capacitance using doorknob capacitors
> Toroid  - 16? x 4?  using 4? aluminum duct
> Spark Gap ? 8  - ¾? CU pipe segments with 1/16? 
> in between each. Used only 7. TCBOR/RQ  style
> Filter ? Terry Filter
> Control Box  - 7.5 Amp variac. 10VR6 EMI filter, 
> fuse assembly, on/off switch, MOV
>
>
> Saturday night  I fired it off.  I started at an 
> easy  6? gap to grounded target. No problem, it 
> easily struck it. Then I moved the target to 
> 13?. Once again, it struck the target. At this 
> point the variac was about  75%  turned on.
>
>
> I next moved the target to 18?. It had a hard 
> time hitting this one. So I moved it to 16? which again worked.
>
>
> I did turn the variac all the way up which 
> pushed 140 volts through the NST.  And then it 
> blew my fuse(6Amp) in my power control. I 
> installed a fuse on both hot and neutral of the 
> 120v supply. However it blew the fuse on the 
> neutral. Hmmm. Still trying to figure out why it is doing this.
>
> Also another problem I was having was corona 
> buildup on my capacitor assembly. I use some ¾?x 
> 1/8? wide copper  bar.   Two rectangle forms 
> were made so I could mount the caps between the 
> two.  However, I cut the bars at 90 degrees and 
> it would jump from the top rail to bottom rail 
> when the variac was turned up only on the 
> corners . I have lately redone the bars using ½? 
> stock and rounded the corners on the grinder. Hope this will help.
>
> While I would like longer sparks, I still 
> consider it a success at this point.
>
> Somethings to do:
>
>             1. Wrap a 28 AWG secondary.
>             2. Try MMC
>             3. Change primary tap
>             4. Pictures of coil and operation
>
> Thanks,
> Dirk Stubbs
>
> --