Re: 5MV, 312kW

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Bart Anderson <classi6-at-classictesla-dot-com> 

Hi Finn,

Good idea using Inca!
With the topload on the system above the groundplane, Ctop would drop it to 
around 215pF and pull the system to 37 kHz. The primary would then need 1.5 
turns at the same cap size. The primary would need a little more work.

Here's about what it would look like
(complete with 6 foot stick-man for comparison),
http://www.classictesla-dot-com/temp/5mv.gif

One other item would be the "small" 312.5KW at 50kV. Vp would be down 
around 39% putting Vtop at 2.8MV at 100 bps. Leaving the system as is, we 
could drop the breaks down around 41 bps or leave at 100 and up the power 
to say 750KW!

Take care,
Bart



Tesla list wrote:

>Original poster: Finn Hammer <f-h-at-c.dk>
>All,
>
>To arrive at 5MV on the top, the toroid has to be the right shape and size 
>to suppress breakout at lesser voltages.
>It _could_ look like this in INCA:
>* 5MVtoroid
>
>Lcenter terminal 20 0 2 1.17 2
>Cedge terminal 20 2 2 0.83 0 180
>Cedge terminal 20 2 2 0.83 0 -180
>
>and would then be :
>Minor diametre: 1.66 metre (65")
>Major diametre: 5.00 metre (196")
>Chip in with 250pF of topload and
>  3125 Joules of energy........
>
>Running the coil below it, at 100BPS, would require 312.5kW
>
>Let`s be bold, without being utterly rediculous, and charge the primary 
>capacitor to 50kV, it will then have to be 2.5µF
>
>Pairing this cap up in a tank with a primary coil that has 2 turns, 
>starting at 70" diametre, 10" spacing and 15.6µH will make it ring at 25kHz.
>
>All we need is a secondary that is 50" in diametre, 250"long wound at 3 
>turns per inch.
>
>Assuming 2nd. notch quench, and a coupling of 0.122, the energy will be 
>transferred after 13 cycles/break, or a total of 0.052secs/sec. Ringing at 
>5.2% of the time, there should be ample time to charge the cap btwn. bangs.
>
>I`ve used INCA, ballpark numbers, and wintesla (Yeah, that`s right: the 
>reg`d copy), for this brief design exercise which untill someone points 
>out an order of magnitude error, suggests that a 5MV coil is not at all 
>that unrealistic, not being concerned with the aspect of funding.
>
>Cheers, Finn Hammer
>
>
>
>Tesla list wrote:
>
>>Original poster: dhmccauley-at-spacecatlighting-dot-com
>>I seriously doubt they were even close to 5MV.  There are problems with this
>>that are blatantly obvious.
>>1.  If this was a classic magnetically coupled tesla coil, that kind of
>>voltage could never form on the discharge terminal (topload) of that
>>secondary without
>>first striking over to the primary at a much lower voltage.
>>2.  The topload would have to be absolutely huge to allow that kind of
>>voltage to build-up.  Small toroids would have a much lower break-out
>>voltage and there would be
>>a discharge at a much lower voltage that obtainable.
>>3.  Also, with only 120mA at 15kV, there is not enough power available to
>>get 5MV in a single discharge cycle unless you were
>>charge pumping a topload capacitor or similar over many cycles.  The gain is
>>approximately = 333 which is ENORMOUS!
>>Since Gain = SQRT (Cp/Cs) the secondary capacitance (self-capacitance of
>>secondary + topload capacitance) would have to be approximately 110,000
>>times
>>smaller than the primary capacitance!  Considering you new a large topload
>>to begin with to allow the voltage to build-up that high, you would have a
>>very large
>>primary capacitance and a 15kv/120mA transformer would NEVER be able to run
>>that.
>>I may be wrong here, but I think even the largest pole transformer tesla
>>coils (>30kW) would have trouble getting to 5MV output!
>>
>>Dan
>>
>>  > I read somewhere a few years ago on the TCBA newsletter (I think) about a
>>  > team of coilers (pro physisicts? can't remember) that made an 8"x40"
>>  > secondary with ~7000 turns of 42 awg. They managed still to get 5 million
>>  > volts out of it with if I remember right a 15/120 supply. I take it that
>>  > higher voltage doesn't necessarily mean longer spark, but am I 
>> overlooking
>>  > something else? I don't think they mentioned the output length, but 
>> 5MV is
>>  > hard to picture short.
>>  >   What if I keep the primary inductance high and add a bigger topload?
>>This
>>  > was my original idea, but was thinking that adding a breakout point
>>reduces
>>  > the effective capacitance, or does it do the equivelent of making it 
>> a big
>>  > leakier capacitor? Can't test this without my scope and kinda chicken to
>>try
>>  > since it's not a robust tube unit.
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