Stationary and RSG material below
Updated: July 25, 2004
Date : Tue, 20 Jul 2004 21:09:56 -0600 - Subject : DC Spark gap coils, why not current limit on the LV AC side?
I'm interested in the idea of DC Tesla coiling, and was wondering, why is it that you cannot simply put a ballast on the LV side of your 60 hz AC step up transformer and use that to prevent your rectifiers from blowing when the spark gap fires? I understand this would not allow for the doubling of the peak voltage of the capacitor like when a charging reactor is used on the HVDC output, but it seems like it would limit the current. I guess the problem of rotary gap power arcing still exists when a ballast is placed on the LVAC primary side of the transformer? Eric.
Date : Wed, 21 Jul 2004 07:18:50 -0600 - Subject : Re: DC Spark gap coils, why not current limit on the LV ACside?
Original poster: Greg Leyh
Actually, the circuit would work just fine as a resonant charger with the
inductor in the primary circuit -- complete with the desired voltage doubling on
the load capacitor.
In many ways it would be an advantage to place the inductor in the lower voltage
primary circuit. The disadvantage to this scheme however would be the voltage
overload seen by both the primary and secondary coils of the HV transformer --
both would suffer a 2x voltage stress during the resonant charging cycle.
Locating the inductor after the rectifiers places the 2x stress solely on the
rectifiers, thus relieving the transformer. GL.
Date : Wed, 21 Jul 2004 07:18:05 -0600 - Subject : Re: DC Spark gap coils, why not current limit on the LV ACside?
Original poster: "S&JY"
Eric, I have solved to my satisfaction the problem of DC power arcing. I use DC
resonant charging, with the inductor being about 200 mH. The key is to charge
the tank cap through one set of gaps on a RSG, then use another set of gaps to
discharge the tank cap through the primary coil. As the rotor turns, this
action repeats. My RSG has 8 spinning electrodes and two sets of stationary
electrodes. There is never a spark gap directly across the DC power supply -
resonant inductor - deQing diode, so there is no power arcing. Break rates can
be as slow as you want. Steve Y.
Date : Wed, 21 Jul 2004 11:53:44 -0600 - Subject : Re: DC Spark gap coils, why not current limit on the LV ACside?
Original poster: robert heidlebaugh
Eric: DC coil acts differently from an AC coil. When the gap fires a dc
short circuit is sent through the diodes to the filter cap power source blowing
the diodes. A simple solution is to add a disconnect coil just after the
diodes to isolate the diodes from the short circuit. A very low inductance
will not affect your circuit, but will protect the diodes. I use a high voltage
coil made of 15 turns of house wire 1 inch dia and 6 inch long air core with no
coil form, quick and easy. For long term use I wind a toroid coil of high
voltage wire wound on a large toroid core such as the ferrite core of a
deflection coil of a TV monitor. Good luck, Robert H.
Date : Wed, 21 Jul 2004 11:54:09 -0600 - Subject : Re: DC Spark gap coils, why not current limit on the LV ACside?
Original poster: "Dr. Resonance"
You might also try hooking a 500 pF 40 kV ceramic style cap directly across the
spark gap. Early wireless pioneers used this method to obtain a "negative
resistance" in the spark gap. The cap is charged and fires to
ionize the plasma thus saving the tank caps energy to provide the resonance
without losses. Poulson used these techniques and others to make the spark gaps
more efficient. Dr. Resonance.
Date : Fri, 23 Jul 2004 12:07:02 -0600 - Subject : negative resistance....Re: DC Spark gap coils, why not currentlimit on the LV AC side?
Original poster: "dave pierson"
>You might also try hooking a 500 pF 40 kV ceramic style cap directly across the
spark gap. Early wireless pioneers used this method to obtain a "negative
resistance" in the sparkgap.
Any arc or spark is inherently negative resistance over much of its range.
>The cap is charged and fires to ionize the plasma thus saving the tank caps
energy to provide the resonance
without losses. Poulson used these techniques and others to make the spark gaps
more efficient.
Poulson also used arcs as oscillators, using the negative resistance
characteristic. I'm unfamiliar with his using spark techniques, that may
be just me....
(has anyone tackled an _arc_ CW Tesla Coil? 8)>>)
best, dwp.
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