[Home][2014 Index] Re: [TCML] Question on Dummyload-Testing in DC ResonantChargingcircuit, similar pursuit [Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] Question on Dummyload-Testing in DC ResonantChargingcircuit, similar pursuit

Hi Stefan, et all

Yes you are probably right about the dummy load although it seems to me the
energy not transferred into a secondary would be wasted without it. Clearly
it does have to go somewhere. Much of it would go into the resonate magnetic
field, though unloaded. Clearly the secondary transfers as much of the
energy as we can get into it!

I agree this big inductor does not lend itself well to resonance charging,
however; it would still charge the tank to 24KV without breaking a sweat. I
could run an external inductor as the internal inductor sits between two
tallll standoffs, where the heck did you get yours? I like your break rate.
This is a Raytheon charging tank or PS which is labeled -24KV on the output
side of the inductor. I do not know if this is the full inductive kick for
the purpose built inductance. It does imply a smaller capacitance to achieve
higher break rates. I know little about quenching 130 BPS and DC gaps but
have up to 24" 5/8 G10 FR4. I was thinking more along the lines of 18" to
extinguish the arc.  I have wanted to experiment with this truly
Frankenstein-ish monster for some time. The (6) 8020 Tubes have Thoriated
Tungsten filaments which will be bright white and the insulators are a bit
intimidating at 12"!

My original post was about a suitable rotary design. If this doesn't fly,
I'll go classic Tesla with Pig Power. I have both .25" and .5 " electrodes
in "W" and a fixed 9/16" 7 inch that needs to be cut. DC Cox gave me the
pressing specs a long time ago for the slugs into the G10. I seem to
remember there were threaded angled set screws too from the outer edge.
Anybody? Best practices? I have a 12" with 1/8" electrodes I built for lower
power with the help of a good machinist.

Jim Mora

I took a hiatus with Tesla coiling and got into Music and repairing and
building tube guitar amps. Now I have the old fever back again ;-^) Time to
search the archives I suppose...

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Teslalabor
Sent: Sunday, June 08, 2014 1:52 AM
To: tesla@xxxxxxxxxx
Subject: Re: [TCML] Question on Dummyload-Testing in DC
ResonantChargingcircuit, similar pursuit

Hi Jim,

you can not run such a circuit only with a primary in place without a
secondary. The result would be extreme currents through your transformers,
spark gap and capacitor, which would mean total failure of this components.
So I did some calculations concerning the dummyload with the result, that
the halogen dummyload testing is absolutely okay and the very best method
for testing such a circuit without messing arround with sparks... ! In my
case it consists of 20 halogen bulbs, each is 240V 500W.
10 of them are connected in series and 2 of this groups in parallel, giving
a 10kW Dummyload. The resistance of one bulb is 100Ohm when glowing, so 10
of them in series is 1kOhm, 2 groups in parallel giving 500Ohm total of my
The dwell time of the spark gap is arround 500us, so this is enough time to
empty my 50nF capacitor during each bang.

Jim, I think you need another charging reactor, the Burnett-Equations will
show you. This 150H inductor, built into your HVDC Supply, is not suitable.
It's inductance is much to high, I think it is not possible to build a
properly resonant charger with this. Also 24kV could mean some trouble, 
remember that the tank cap is charged to twice that voltage, in your case 
48kV !

Some short facts about my coil: The system is designed (by using the
Burnett-Equations) for running 7kW full power @ 400bps. I am actually
testing it with my 3000rpm Schraner-Style SRSG (Hello Kurt :-) ), running @
only 300bps fixed (it is not variable in speed). The variable speed rotary
is still in progress...  System is 3-phase powered, with a 6-pulse
rectifier, DC Charging voltage is 13,3kV. The tank cap is 2 Maxwell Caps in
series, each 40kV/100nF, giving me 80kV / 50nF. My charging reactor is 12,4
Henries. The energy is fired into the 10kW dummyload, mentioned above. The
performance seems to be amazing. Primary and Secondary coils will be build



Tesla mailing list