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Sonderman Makes Sparks



---------- Forwarded message ----------
Date: Tue, 7 Oct 1997 12:27:26 -0400 (EDT)
From: Esondrmn-at-aol-dot-com
To: tesla-at-pupman-dot-com
Subject: Sonderman Makes Sparks

I did a lot of testing last night and finally got some reasonable results.
 Not great but better than I have got for a long time.  I will list all of
the test results here and maybe someone can give me some more ideas.  My goal
was to find combinations of primary set up that would allow the maximum input
power without firing the capacitor safety gap.  The main H.V. safety gap
never did fire so when I say the gap fired, it is the cap safety gap I am
referring to.  It was set at 5/8".  I was using a 40" toroid with a wire
laying on one side pointing to a grounded wire about 3 feet away for most of
these tests.  The primary was tapped at 11.75 turns which is the best tune I
found from previous tests.

Test set up # 1:  Took the welder out of the circuit and used resistive
ballast only.  No resistors in series with the H. V. leads.  With R = 22
ohms, I could go to full variac voltage, smooth control and no safety gap
firing.  Primary current was 6 A and primary voltage (into the pig, 60:1
turns ratio) was 160 V.  I decreased the ballast resistance until I got to
7.0 ohms, the primary I = 16 A, primary E = 200 volts.  Now I was getting
popping in the rotary.  I don't know how else to describe it.  I hear pops
(not real loud like the safety gap makes) and see light flashes coming out of
the rotary box.  I actually had this problem back with the old configuration
that used to make the 80" sparks.  Since it sounds like a symptom of a
problem that I don't want, I put the static gap back in series with the
rotary.  Popping went away, primary I dropped to 14 A. Decreased R to 4.8
ohms, I = 14A, E = 225 V.  Works ok still.  Decreased R to 4.0 ohms and the
popping in the rotary comes back.  Is this some kind of kick back condition?

Test set up # 2.  Again using only resistive ballast and adding series
resistors in each H.V. feed line (near the pig, on the safety gap board).  I
used two 300 ohm, 50 W resistors in series on each side - 600 ohms total in
each leg.  At R = 4.0 ohms, primary current is 14A, E = 225V.  Gap firing is
a little erratic, discharge sparks are hitting the ground wire, overall
performance not very good.  Decreased R to 3.3 ohms and now the popping is
back in the rotary.

Test set up # 3.  Same set up as #2 only the welder has been placed back in
series with the resistive ballast.  With R = 22 ohms, welder set on minimum,
I = 6A, E = 180V, the secondary discharges are much hotter and louder than in
the previous tests - with no inductance (welder) in the primary circuit.
 Changed welder setting to maximum (230 A setting) and performance is worse.
 Set welder back to minimum. Decreased R to 4.0 ohms and performance is good,
getting 44" discharges, I = 15A, E = 245V.  Decreased R to 3.3 ohms and the
safety gap starts firing.  So far, the best performance is with the welder in
the circuit and when the series resistance gets too low, the cap safety gap
fires.  I would think this indicates I am getting 60 hz resonance now and it
appears I want some for best performance but not so much that the safety gap
fires.

Now I set the welder back to maximum and performance is better.  It seems
when R is high (10 to 20 ohms) the ballast inductance needs to be high.  When
R is low (3 to 5 ohms) the ballast inductance needs to be low - for best
performance.

With the welder set on maximum and R = 4.0 ohms, I started to slowly increase
the rotary speed.  I got up to maybe 400 to 500 BPS, performance got much
better and the safety gap started firing again.  I backed R off to 4.8 ohms
and now get 57" sparks and an occasional firing of the safety gap.

Well, that's it.  I am getting reasonable performance but not what I used to
get.  The coil is working well once I get the right combination of
everything.  Now, what do I do next?  I want to get the primary current up to
30 amps where I used to be able to run.  15A at 245V is about 3.7kva, I
obviously want to find some combination that will allow me to put in as much
power as I have available which is probalby 7 to 8 kva.  Is it possible that
this 6" coil system just won't accept that much power?

Maybe I need to loosen up the coupling some more.  Now the lowest turn on the
secondary is about an inch or two above the lowest turn on the primary.  I am
using a saucer shapped primary wound at 30 degrees.  If I am not getting
splitting on the secondary, and I don't see any, maybe I could tighten up the
coupling?

Now I can't believe how lucky I was when I originally built this system.
 With a lot of help from Richard Quick and a lucky selection of components
and layout, I once got 80" sparks.  I wonder if it will happen again.

Comments welcome, please.

Thanks, Ed Sonderman