Re: 3 probably awful beginners questions ;-)

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

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <Esondrmn-at-aol-dot-com>

In a message dated 1/14/03 7:00:16 AM Pacific Standard Time, 
tesla-at-pupman-dot-com writes:


>Hello ererybody.
>
>Im quite new to coiling, but last weekend I finally got my first coil
>started for a first light.
>But after reading a lot of Stuff about configuration and tuning there are a
>few Questions left up to this point.
>
>1: I Use a 10KV / 40Ma Power-Supply with a 11nF cap at about 185KHz. The
>Tesla-Calculator I have tells me I won't ger more power / longer arcs by
>increasing the xformer's powerlevel, is that right? I only get 14" arcs to
>a grounded piont with a 900turns coil ( 1,5ft high, 4"dia  with a 4"/15"
>toroid ) and I wonder if more Power would get the thing done or if the cap
>yust can't store more energy.
>
>2.: I measured out the coil with a signal-generator ( hope the term is
>right ) and osziloscope, but with the values I received the coil wouldn't
>work at all, so I tuned by hand an It started working.( far away from the
>point I measured out ) But I can chang almost 1 turn up/down on the primary
>with no measurable difference in performance, is that normal?, shouldn't
>there be en exact point?
>
>3: My sparc-gap ist a static with an fan, rather unprofessional design.
>When then Fan is at full power ( this takes aprox 3 secs after Power on )
>the arcs get a little longer but I get very very bright arcs from the
>ground point of the SEC to the inner winding of the PRI, may my coil be
>extremely out of tune but run anyway? the two parts are about 3 inches
>apart, so at about 15KV I thought nothig should go wrong.....?! may this be
>the point where I loose Power? ( I#m almost sure a arc of that size will
>consume a lot of power, ) I saw qiute similar coils having almost 3 times
>the arc-legth..
>
>
>I'd be glad to hear some of your experts opinions to these 3 questions..
>
>Thank you very much in andvance
>
>sincerely
>
>Christoph Bohr


Christoph,

1.  I would say, yes, more power will result in longer sparks for your 
coil.  I have a 3.0" diameter coil, 13.1" winding length, # 28 awg wire, 
using a .015 ufd cap and a 12 kv 60 ma transformer and get about 30" sparks.

2. With my coil, I get about 1/2 turn change on the primary where the 
performance seems to be the same.  If I find the best performance at say 
turn 7.5, there is a noticable difference at turn 8.5 or turn 6.5.  Your 
primary components should be mounted as close together as possible and 
connections should be made between them with at least # 12 or #10 
wire.  What is the primary wound with?

3.  You are correct, the inner turn of the primary should not be arcing 3" 
to the ground point of the bottom of the secondary.  I think I only have 
about 1.5" of clearance there.  What kind of ground does the secondary 
have?  I ran some numbers, making many assumptions, and found that your 
coil should be tapped at turn 10 or 11 on the primary.

Good luck, Ed Sonderman