Re: Mini OLTC is getting 9"

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

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi Steve,

At 04:25 PM 3/16/2003 +0000, you wrote:
>At 18:46 15/03/03 -0700, you wrote:
>>Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
>>
>>Hi Steve,
>>
>>Wow cool!!
>>
>>Same hot mean sparks as mine.  Interesting that you have so much control 
>>over BPS!  Does it make any difference??  With the OLTC being so highly 
>>controlled otherwise, you should be able to tell if say 120 bps is any 
>>better or worse than say 600 BPS...  That is a very old question that 
>>maybe you can study!
>
>Playing with the OLTC has been really interesting and I learnt a lot about 
>spark length and so on. I basically found that bang energy is by far the 
>most important thing. Big bangs at a low BPS seem most effective for 
>building streamer length. For instance, If I turn the bang energy down by 
>a factor of four, then turning up the BPS by a factor of four doesn't 
>restore the lost spark length.

Oh!!!  That IS interesting!!!  One big bang beats four little bangs...


>However, if the BPS is too low, then the discharge channel will have time 
>to cool between bangs and you'll lose the streamer growth effect where the 
>next bang grows out of the end of the previous one. On my OLTC the 
>streamer growth starts at about 500bps when the bang energy is max. At 
>lower bang energies it never starts at all: I just get a little VTTC-like 
>brush discharge.
>
>I found it interesting to compare with my conventional coil. It has a bang 
>energy of 1.9 joules which produces an arc about 10" long at 1bps. At 
>100bps this increases to 17" and at 500bps it's 30". Whereas the mini 
>OLTC, with energy of around 0.43 joules, gives 5" at 2bps and 9" at 1200bps.
>
>Also, you can compare with the 1.7 * sqrt (p) formula. It was meant for 
>120bps systems, and suggests that my conventional coil would do 53" if it 
>were still 1kW but ran at 120bps rather than 500.
>
>My conclusion from all of the above is that high bang energy is doubly 
>important, because it makes bigger sparks in the first place, and also 
>responds better to upping of the BPS. So y'all keep saving those empty 
>Corona bottles ;)

So relatively low BPS with big bang energies seems like our goal!!  Lower 
BPSs allow us to store more energy for big bangs.


>>Wonderful to know that there are now two!!  I bet you don't miss the big 
>>transformers (not knowing how big your DC supply is).
>
>The whole system is totally self contained and can be picked up in one 
>hand. It's a success on that score.

Yeah!!  I am getting tired of lugging iron around ;-))



>>I do note that for a given power we seem to be getting about the same 
>>type and length of streamers even though the frequency is 4X different.
>
>I looked at the pic you sent and it does seem to be a similar thing. Is 
>that the wall of your shop the coil is sparking to?

It is another toroid:

http://hot-streamer-dot-com/temp/OLTC08-25-03.jpg

http://hot-streamer-dot-com/temp/OLTC08-25-01.jpg

http://hot-streamer-dot-com/temp/OLTC08-27-04.jpg

I "wish" that was my shop, but it is Bill Lemieux's HV lab in Denver.


>Also, how did it work just forming streamers into the air? I'm wondering 
>because I heard that a higher frequency would give better streamers, even 
>though arcs would be no different. This was a very short burst of 1200bps 
>on 340V filtered DC: The discharge looks quite halfwave SSTC-like.

My OLTC seems to have trouble making air streamers like one would expect at 
the present power level.  I still have 4X the power to go, so I am hoping 
it will really take off.

>http://www.scopeboy-dot-com/tesla/oltc1200streamer.jpg

Wow!!!

Cheers,

         Terry


>Steve C.