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RE: 3 probably awful beginners questions ;-)



Original poster: "Lau, Gary by way of Terry Fritz <teslalist-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

Hi Christoph:

Good questions!  Comments interspersed:


 >Original poster: "Christoph Bohr by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <cb-at-luebke-lands.de>
 >
 >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.

Assuming that you're using a static gap, using a larger power supply (i.e. 
able to source more current) will definitely increase performance. If more 
current is available, whatever cap you're using will still charge to the 
same voltage, but it will do so more times (bangs) per second, and this 
results in longer streamers.

 >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?

If you're getting 14" arcs, things are probably pretty close to being 
in-tune.  Some people report fairly sharp tuning, and others like yourself 
report it to be fairly non-critical.  I've never heard an explanation 
offered for this, but it's "normal".

 >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..

Are you saying that your primary is arcing to your secondary base, over a 
distance of 3 inches?  That's definitely not normal!  Is this arcing 
through air or is it across the surface of an insulator?  An inch of air 
separation should be adequate.

Would you be using air core chokes?  I did briefly and had all kinds of 
arcing where it should not have.

I assume your primary is a flat pancake design?  Is it possible that the 
pri-sec coupling is too high?

 >I'd be glad to hear some of your experts opinions to these 3 questions..
 >
 >Thank you very much in andvance
 >
 >sincerely
 >
 >Christoph Bohr

Regards, Gary Lau
MA, USA