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

[cho yan ping <cho_yan_ping@xxxxxxxxxxx>]

Hi Gary,

I posted two photos on http://drop.io/chester_tesla1.
The first photo is my multi static sparks gap, which I used 4, and total length is 4mm.
The second photo is a 5"sparks obtained by bending the bottom terminal to the top by a wire.The sparks obtained in this way is weak, and not likely due to resonance. 
Also I have to raise the primary until half the height of the secondary coil. So I don't think that my coil is working.

I am thinking if my coil is out of tune or problem of grounding?
I calculate by Teslamap and tapped at 4-6 microHenries, but no open air discharge or corona is obtained.
I tried to ground by a 15sq. foot iron fence, no result obtained.
I also tried to use main ground, I don't know if this could hurt if only lamp and fan are connected in the same circuit.
However, still no open air discharge obtained.

What should I do to diagnose and the problems?
Thanks for any advice!

Regards,
Chester





--轉寄的郵件附件--
From: Gary.Lau@xxxxxx
CC: 
To: tesla@xxxxxxxxxx
Date: Thu, 23 Jul 2009 17:05:51 +0000
Subject: RE: [TCML] Please help with my non-working tesla coil.

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
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