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Re: [TCML] Sec design trade-offs and considerations



Chris,

You haven`t built enough momentum for suspense, but so far you have got one of us confused.

Is the 1000uF cap merely a storage and smoothing cap? @250V?

Then dump this 250V into a 10nF cap. I`d be surprised if you can get breakout from that. It`s 0.3uJ

About your SISG coils.
You *could* have worked around the problems of syncronising to the mains frequency by going full DC, with resonant charging of the tank cap. Like I did, and got full flexibility from 1-1200+ BPS.

Another note, When you removed the SIDAC`s and replaced them with opto`s, you put the individual IGBT in grave danger. I doubt it would work. The reason you can stack the SISG primary modules lies in the fact that the SIDAC`s clamp the voltage across each IGBT until they turn on. After turn on, they do so themselves.
Opto`s can`t do that.

Cheers, Finn Hammer


Chris Swinson skrev:
Finn,

I documented many many pages on its operation, it actually begun as a modified SISG, and there is many many pages on that also. I have not updated the current pages as yet, but a lot of it is not valid anymore anyway so there is nothing I can post yet. You could look over my first notes and ideas which are on my website, but these are only ideas and simulations.. to be honest probably not worth looking at, well unless you want to then sure! you could view my SISG updates there, plus many other ideas. Though after that work, I changed the design again to a high Q system....

My SISG pages were to fire the "spark gap" on the zero crossing of the AC wave, rather than shorting out the supply rails via 200R like terry's does.... But then I went onto opto drives in parallel with the IBGT's instead of series.. though I aborted it in favour for my new design.... Though I did get all the bits to build it as all documented!

Though once the design is working to some fashion then at least I can post a known working circuit.... If I post the circuit then it opens ups a lot of talk on it (which can be good) but I don't want to get too involved in chats about it at the moment. I already went though all the if's and but's during the last 8 months myself any currently do not want to open it all up again for debate for another 8 months on a circuit which has not been even tested yet, would be like speculation so I would rather keep it hush hush for now until I have some valid data and experiments at least to put to the group.

As the design gets tweaked it is not even it its final stages yet, it may not even work, so I do not see any point in taking up bandwidth on it at the moment... its got to the "build it and see" part and even though first trial runs looked promising there is still some way to go...

I can tell you the max voltage on the "Tank" can be 250VDC, this is an limitation of the capacitors used. Even so, 1,000uF at 250VDC, well no need to state how many joules!

I worked out that at 25VDC input my High Q system *should* equal a 500W SG coil. Though as this design is totally backwards to normal coils, errors and omissions expected!

1,000uF charges the 10nF 1uH primary which gives 2mhz.. the 1,000uf only delivers the Joules to the primary circuit, in a way the 1,000uF is equiv to a transformer supply... Though the 1,000uF is also part of a DC resonant circuit at 400hz... There is not much more to it, but to go over all the operation..... well just look at all my posts so far on SG coils.....

I do however hope to have it finished in a few weeks. so will post the final diagram then working or not along with all the operation notes I have documented over the past few months...

No doubt once the circuit is working in some respect, others then can chip into the development and make improvements or suggestions... though for now I have enough confusion about things without going over oddball high Q designs also!

It is probable that it will look like a OLTC type design, but with high Q in mind... If there is enough interest then I will try and keep the list posted with progress as it happens....

Sorry to keep you in suspense!

Chris




----- Original Message ----- From: "Finn Hammer" <f-h@xxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Sunday, November 25, 2007 7:11 PM
Subject: Re: [TCML] Sec design trade-offs and considerations


Chris,

I have a problem visualizing how the 1000uF cap takes part in the 2mHz oscillation.
Could you post a schematic?.
You mentioned high Q and low voltage. What voltage do you have in mind?

Cheers, Finn Hammer


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