[Prev][Next][Index][Thread]
Re: Coil Experiments in Austin
Tesla List wrote:
>
> Subscriber: lod-at-pacbell-dot-net Tue Feb 11 23:21:04 1997
> Date: Tue, 11 Feb 1997 21:28:27 -0800
> From: Greg Leyh <lod-at-pacbell-dot-net>
> To: tesla-at-pupman-dot-com
> Subject: Coil Experiments in Austin
>
> Hello all,
>
> Are there any coilers in the Austin area on the List? I'm bringing
> my coil along with the SRL folks, to the show in Austin on March 28.
> I'd like to meet any coilers there, and get some suggestions on good
> places to get surplus HV equipment, in case something goes up in flames!
>
> There will be opportunities for some interesting experiments this time,
> since I will not be allowed to attach to the local feeder -- instead
> they opted to rent a construction generator in order to isolate the coil,
> and 175 kVA was the smallest size unit that they could find! I only need
> 50 kVA of that to run the coil, but it is now my goal to somehow dump the
> full capacity of that generator into a 30 foot electric arc.
>
> I hope to do so by bootstrapping the secondary with a 100 kJ, 25 kV bank
> of capacitors, fed by a 100 kVA capacitor charging power supply. In this
> way whenever the streamer connects solidly with a grounded object, the
> caps will disruptively discharge thru the arc, followed by 100 kW of CW from
> the DC power supply. Then when the streamer breaks away or is interrupted,
> then the power supply will recharge the caps.
>
> Any comments regarding the feasibility of this setup will be appreciated.
>
> -GL
Greg,
Shazaam!! I hope you're going to take pictures and video of this for
those of us who can't make it! :^)
Are you proposing to elevate the base of the coil to the +25 KVDC via
the 100 KVA charging source and capacitor bank? This would leave it
grounded "AC-wise" through the capacitor bank, but charged DC-wise to 25
KV. 100 kJ at 25 KV implies about 320 uF - this should _certainly_ look
like a pretty good "AC ground" to the base of the coil.
I'd think the trick would be making sure that you don't arc to something
you don't intend to. The inductance of the coil and voltage drop in the
arc should limit the amount of current once you've arc'ed to a good
ground return to the other side of the caps... to maybe two or three
thousand amps. 100 kJ is a fierce amount of energy! If I remember right,
your secondary is wound with fairly large wire, and may be able to take
the surge current. However, I'd also guess that 100 kJoules in this
configuration would cause a fairly long-duration arc once struck.
Are you putting grounded metal plates around the coil to
prevent blowing chunks out of the floor? Can your discharge
terminal take the heat at the discharge point without melting through
during a sustained discharge? With the large capacitor bank and the the
substantial series inductance of your secondary, the "tank" circuit
you'll form when this puppy discharges will probably oscillate at under
100 Hz! It should be... AWESOME!
BTW, my brother-in-law lives in Austin - where is SRL and what show are
you talking about? Man, I wish I lived in Texas about now!!
Safe Lightning-bolt generatin' to you, Greg!!
-- Bert --