Re: Coil Doesn't Fire

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

Original poster: "robert heidlebaugh" <rheidlebaugh-at-desertgate-dot-com> 

Jim: Just looking at your data I see several problems.        1) your
transformer is 15000 Vrms that is (1.414 x 15000=) about 22000 Vpk, and your
capacitors are (1500 x 8=) or 12000 V . That is way to low a voltage.     2)
your capacitance Total is ( o.0043 x 12 / 8=) o.00645 uf which is to low.
3) your primary is only 14 turns. With a low capacitance your primary
resonant frequency is probibly way to high and you are not reaching a tuning
point. Add about 14 more turns of bare house wire to your primary coil for
testing then if you reach a resonant point you can splice the primary to the
correct number of turns.
        Hope this helps
               Robert   H
-- 


 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > Date: Thu, 16 Sep 2004 17:36:56 -0600
 > To: tesla-at-pupman-dot-com
 > Subject: Re: Coil Doesn't Fire
 > Resent-From: tesla-at-pupman-dot-com
 > Resent-Date: Thu, 16 Sep 2004 17:39:53 -0600
 >
 > Original poster: Esondrmn-at-aol-dot-com
 >
 > In a message dated 9/15/04 11:52:36 AM Pacific Daylight Time,
 > tesla-at-pupman-dot-com writes:
 >
 >
 >> Original poster: JBarrett-at-trumbullcorp-dot-com
 >>
 >>
 >> Hey I bet no one has had this problem. Just kidding!
 >>
 >> Transformer:
 >> 12,000 Volt 30 ma
 >>
 >> Caps
 >> Panasonic ECW-H 0.0043uf +- 3% W.V. 1500 VP-P 2500 VDC with a 1 megaohm
 >> bleeder resistor across each cap. 8 in series 12 parallel.
 >>
 >> Secondary
 >> 21" of 22 guage wire on a 4 1/2 inch PVC Pipe
 >>
 >> Primary
 >> 14 turns of 3/8 copper tubing mounted on 3/4 inch plastic risers set at 30
 >> degrees. The inner radius is 5 1/2inches.
 >>
 >> Torid
 >> 22 inch major radius of 4 inch flexible dryer duct mounted on aluminum foil
 >> covered 1/4 inch plywood.
 >>
 >> Spark Gap
 >> Air cooled at 25 psi
 >>
 >> Grounding
 >> 2- 4 foot ground rods driven into ground and soaked with h2o.
 >>
 >> I believe my caps are the major source of the prolem however someone
 >> pointed out that my transformer is a little small too.
 >> Any other thoughts?
 >>
 >> JIM
 >
 >
 > Jim,
 >
 > What is the coil doing?  Is the primary spark gap firing?  With a low power
 > coil like this, you don't need a blown gap.  A static gap made of 1.0"
 > copper tube sections about 3.0" long would work fine.  Use about six copper
 > tubes with about .020" to .030" gap between each.  Then start by using only
 > about four of these gaps to see if you can get the coil running.  It is a
 > good idea to use a small fan for cooling on the gap.
 >
 > If the gap doesn't fire, either something is wrong with the transformer,or
 > the caps or it is not hooked up correctly.  I am not familiar with the caps
 > that you are using.  Are these the good poly/metal foil caps?  The total
 > equivalent capacitance is only .0065 ufd.  That is kind of small for a coil
 > of this size.  Some quick calculations show the coil should tune as is with
 > the primary tap set at about turn 12.5.
 >
 > I see Gary mentioned the bleeder resistors.  That is a good catch.
 >
 > Ed Sonderman
 >
 >