RE: New coiler :)

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

Original poster: "Chris Sartler by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Chris.Sartler-at-adicon-dot-com>

Hi, 

Your main problem is probably the tuning issue and or mismatch of the
capacitors and primary inductance.  This happened to me on my first coil.
The caps and primary turns must be close to the needed values(for resonance)
for tuning to be feasible. The amount of capacitance required is determined
by 2 things A) Resonant frequency B)Max NST/MOT/PIG peek current.  Then the
primary inductance can be figured out after that. The idea is that one
wishes to achieve resonant frequency in the primary circuit at the frequency
determined by the secondary. The resonant frequency of the secondary is
determined by construction(e.g. length,# of turns,Type and size of discharge
terminal). Your best bet would be to download WINTESLA and input the
parameters not easily changed.  Then determine approx. what capacitance you
need and the amount of turns to start at when tuning.  Otherwise it sounds
like you should be able to obtain more than a few measly week sparks! :) A
single spark gap not quenched will be fine for a small coil such as this. I
don't know about the overcoupling issue , I don't think that would be a
issue right now(somebody correct me if I am wrong). Sanding and Drying the
PVC helps increase efficiency but will not "KILL" the coil unless it is
really contaminated.  The wax would not have been my first choice, but
should be ok.  The discharge terminal is also ok, but should be figured into
the secondary construction as it effects the resonant frequency by
increasing secondary capacitance.  As far as the gap goes, I usually start
with a small gap and work my way up as the coil get into tune.  The gap size
will effect max output also.  If too large the coil will not fire at all(and
possibly kill your caps).  If too small the coil will have a weak output
because the caps will not have time to charge fully before the gap ionizes. 

Hope this helps,
Chris

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, September 21, 2001 1:36 PM
To: tesla-at-pupman-dot-com
Subject: New coiler :)


Original poster: "Jonathan Senger by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <scoobysnax100-at-hotmail-dot-com>

Hey guys,
 
I'm a 17 year old newbie coiler from Auburn, Alabama.  I was
wondering if there are any coilers in my area?  My first attempt 
at a coil was a flop...  I've been looking at the tesla ring and various 
Tesla sites and I think I see a few probs with my design. Sorry if this post
is a bit long.
 
I used a 15kV 30 mA NST, SW caps, and a simple 1 gap spark gap with 
no quenching(could this be the problem?).  My primary was 11 turns of 
1/4" Cu tubing, with 1/4" spacing wound up the outside of a plastic beach
toy 
bucket and secured with cable ties(could overcoupling be the problem?).  My 
secondary is wound on a 1.5 foot long sched 40 PVC pipe with an OD of
3.5"(I just read something about sanding the PVC and baking it in the oven
to 
drive off moisture and then sealing it with varnish, how important is this?)

I painted the PVC with a thin layer of beeswax to help the wire stay while 
I was winding(bad idea?).  I hand wound 20 awg magnet wire for 14"(not 
enough turns?) and passed the ends through a hole in the PVC at each 
end of the winding.  I probably should have used a shellac or varnish to
seal 
it but I don't think it would have stuck to the wax anyway. To seal it i
used
paper 
towels soaked in paraffin(this was probably a bad idea). For a discharge
terminal I 
used a 6" foam sphere wrapped in aluminum foil and rubbed smooth. I had no
idea

how to tune it right so i just tried a bunch of spots, I also didn't know
how
wide 
of a gap I should use.  I was able to get 5 inch very thin(less than a mm
thick)
spindly sparks if I put a grounded cable close to the sphere, but no 
brush discharge or streamers.
 
Any advice would be appreciated, thanks :)
 
Jonathan Senger