RE: [TCML] Please help with my non-working tesla coil.

["Lau, Gary" <Gary.Lau@xxxxxx>]

Hi Chester,

We'll need to know a lot more before we can diagnose the problem.  Is there a way you can post detailed photos of your coil, in particular the spark gap, and relationship of primary & secondary coils?  There should never be sparks between the pri & sec.

When you chose the tap point for the primary, was this based on an observation that performance seemed better at that tap than with more or fewer turns?  In other words, do you have any idea if you are in tune?

Assuming that the stated inductances are correct, we can calculate the primary frequency, but to calculate the secondary frequency we'd need to know the dimensions of the top load.

For your spark gap, is the 4mm the total spacing (sum of individual gaps)?  The typical method of setting the gap width is to set it so that it just fires when only the NST is connected to the gap.

A polypropylene MMC is without doubt a much better choice than a bottle cap.

Adding forced airflow through the spark gap usually helps, but I'll reserve that comment until I see photos.

Regards, Gary Lau
MA, USA



> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of cho yan ping
> Sent: Thursday, July 23, 2009 12:38 PM
> To: tesla@xxxxxxxxxx
> Subject: [TCML] Please help with my non-working tesla coil.
> Dear coilers,
> 
> I built a tesla coil two months ago. However, I never obtained any open air
> discharge at all.
> I am quite dissapointing and hoping for advice from anybody.
> 
> Here is my specification of my  tesla coil:
> Power supply: NST 7.5kV 30mA 50Hz
> Cap bank: Polypropylene Cap 15000VDC 22nF
> Spark gap: Multistatic spark gap 4mm
> Primary coil: Copper tube 3/8" tapped at 4-6microHenries
> Secondary coil: Diameter 3.25" Height 18" Inductance 7.8miliHenries
> Top:Ducting pipe toroid
> Grounding: NST ground and RF are connected to main or to a 15sq. foot iron
> fence.
> Protesction: two 5 microHenries choke coil, no safety gap.
> 
> And the circuit is connected as
> http://www.pupman.com/howto/TANK2.GIF
> 
> The spark gap is firing nicely, there are little sparks between secondary coil and
> primary sometimes.
> However, the top toroid don't seems to give arc even with a breakout point.
> 
> I am thinking if I replace the cap with bottle cap would produce better result?
> Or any other modification would make the coil work?
> Please give any advice, thank you!
> 
> Regards,
> Chester

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla