Re: my coils not up to snuff

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Mark Broker <mbroker-at-thegeekgroup-dot-org> 

I agree with the other posters about the spark gap needing some air flow 
and also that tuning needs to be improved.

I disagree with Robert about the capacitor voltage, since the caps are 
rated at 600vAC.  I would imagine they have a DC rating of 1600V?  If so, 
then I would remove about 9 capacitors (resulting in a string of 16) for a 
value of about .019uF (voltage rating over 25kV).  This is about the 
desired LTR value for a static gap coil.  LTR capacitors prevent 
overvolting the primary circuit components (caps and NST) because the 
resonant rise effect is significantly reduced.  This will also allow you to 
tune with fewer primary turns.

What brand and part number caps are you using?

good luck,

Mark Broker
Chief Engineer, The Geek Group


On Fri, 12 Dec 2003 17:16:52 -0700, Tesla list <tesla-at-pupman-dot-com> wrote:

>Original poster: "Sam W." <HAZAA_69-at-hotmail-dot-com> ----- Original Message -----
>From: <mailto:HAZAA_69-at-hotmail-dot-com>Sam W.
>To: <mailto:tesla-at-pupman-dot-com>tesla-at-pupman-dot-com
>Sent: Monday, December 08, 2003 3:08 PM
>
>I have a coil running on a 12/60 nst
>4.5" x 30" secondary w/21 AWG magnet wire
>Primary:8 turns of 10 AWG insulated wire
>Spark gap is a single static with no pressurized air for quenching
>mmc 25 0.33 uF caps rated at 600VAC in series to make 12500VAC 0.0133uF
>choke 200 turns 21 AWG
>4" flexible aluminum ducting covered in aluminum tape
>2" flex aluminum ducting covered in aluminum tape
>(double toroid)
>
>im getting like 3" breakout, with only 9" going to a grounded pole. I 
>couldnt get any thin walled copper tubing, so i used insulated wire rated 
>at 15 kv. if i replace the primary and change the spark gap will i get 
>bigger sparks? im reading about people with similar setups getting like 
>3-4 ft. sparks. This was my first coil, and i did it for science fair. I 
>was a little dissapointed with performance. I dont want to use a rotary 
>gap, cause i cant get a synchronous motor, and asynchs will blow my nst. 
>PLEASE HELP!