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Re: Barts Coil Desing (was flashing vs. whatever)


From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Sunday, November 30, 1997 4:30 PM
To: 	Tesla List
Subject: 	Re: Barts Coil Desing (was flashing vs. whatever)

Hi Bert, Bart,

> From:   Bert Hickman[SMTP:bert.hickman-at-aquila-dot-com]
> Reply To:   bert.hickman-at-aquila-dot-com
> Sent:   Sunday, November 30, 1997 12:49 AM
> To:     Tesla List
> Subject:    Re: Barts Coil Desing (was flashing vs. whatever)
> 
> Tesla List wrote:
> > 
> > From:   Barton B. Anderson[SMTP:mopar-at-mn.uswest-dot-net]
> > Sent:   Saturday, November 29, 1997 11:01 PM
> > To:     Tesla List
> > Subject:        Re: Barts Coil Desing (was flashing vs. whatever)
> > 
> > Bert,
> > 
> > > <SNIP>
> > > NOW I understand the source of the discrepency! It is essential that
> > > your tank cap and primary be tuned to your secondary/toroid's operating
> > > frequency. Now, for maximum power output you may also choose to "size"
> > > the tank cap to the transformer/ballast power delivery capability.
> > > However, you must STILL keep the system in tune. BTW, the 14.4 KV term
> > > in the above equation is already RMS volts, so it does not need to be
> > > derated by 0.707. This results in a properly "sized" cap value of about
> > > 0.128 uF to match 10 KVA. However, you can easily run the pig
> > > intermittently at 20 KVA which will bring you up to the 0.256 uF cap
> > > previously computed.
> > >
> > > However, when you increase the size of the tank cap, you also directly
> > > increase the amount of energy per "bang". Going from 0.05 uF to 0.256 uF
> > > basically quintuples the energy available when the gap fires. For
> > > example, if your gap fires at 16 KV, you'll have 6.4 Joules of energy
> > > per bang with a 0.05 uF cap, but a whopping 32.7 Joules with the 0.256
> > > uF cap. All other things being the same, the output voltage of the coil
> > > would also increase by a factor of about SQRT(5) or 2.24 times...
> > >
> > 
> > Ok, Now I understand my discrepancy. Thanks! I knew the KVA rating of the pole pig is
> > rated as "apparent power" due to inductive loading, but I didn't know the output voltage
> > was rms. I went back through the calcs and came up with 0.128uF (as you did) equating to a
> > needed reactance af 12.44ohms. This would eventually work out to 16.4 Joules. What do you
> > think, is this still a bit too "Whopping" for the 12.5" x 33.2" Secondary? I definitely
> > want to throw as much "umph" at the coil that it can electrically handle, but then I don't
> > want to kill it (at least on the first couple firings). It might be wise to just go off
> > the 0.05uF and modify the primary to match Xc?
> > 
> > Let me know your thoughts,
> > Bart
> 
> Bart, 
> 
> This is about the minimal length coil for a 0.05 uF tank cap driven off
> a 14.4 KV source. This coil should be deliver 8-9 foot streamers, which
> would be about 3X your secondary coil-length. While you can do quite
> alot to shape the E-Field at the top of the coil by using a larger
> diameter toroid, it's still very difficult to prevent most of your
> strikes from going between the toroid and the strike-ring when your
> streamer length gets much above 2.5-3X your coil length. I'd go with a
> single 0.05 uF cap for now. If you decide later on that you'd like to
> bump the power level up, you can add another 0.05 uF cap in parallel
> with the first and "grow" the other parts of the system to match...
> 
> Safe coilin' to you, Bart!
> 
> -- Bert --

Of course the break rate could be bumped up to get more power in 
without increasing Vout if the smaller cap is used. I agree about the 
strike rail strikes.
    It might be worth using this resonator as an extra coil and 
building a good driver. It ought to tolerate some more Ep like that.
Richard Hull's experiments suggest you could easily get a lot more 
length using it in this mode. In fact, it sounds like a doozy for mag 
operation.

?
Malcolm