RE: [TCML] first coil help

["S&JY" <youngs@xxxxxxxxx>]

Thomas,

Your secondary form, which you describe as a black tube, raises flags.  If
the tube is black because it uses carbon as its pigment, then that may be
your problem.  It may be conductive.  If you have a piece of the black coil
form, use your NST, ground one end of your coil form sample to the NST case,
hold it with something well insulated, then bring the form near one of the
NST HV terminals and see if it arcs to the tube.  If it does, that is
probably at least one of your causes of poor performance.  You should wind
another secondary on another coil form such as a piece of white PVC.  

You can do the same test with your actual secondary.  Ground the winding to
the NST case and bring an edge of the form near your NST HV terminal.

Others have suggested putting a form sample in a microwave oven & see if it
gets hot.  The idea is that if it gets hot, it is not a good coil form
material.  Personally, I think that is not as definitive a test as that
described above.  

--Steve Y.

----- Original Message ----- 
From: "Ryckmans, Thomas" <Thomas.Ryckmans@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Thursday, March 20, 2008 9:43 AM
Subject: [TCML] first coil help



Hello,

I am building my first Tesla coil, but having issues - sparks are
pathetic - about 1 cm from topload to a grounded object. Help is much
appreciated...
<SNIP>

Secondary is using a 130 mm (diameter) black tube, 320 mm high, with
(about) 14 turns/cm hence (about) 450 turns.

<SNIP>
So far, so good. However when firing the coil, I get pathetic sparks
(about 1 cm long) between the top load and a (insulated) screwdriver I
hold above it.
What am I doing wrong?

Many thanks for your comments!

Thomas


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