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Re: Oil filed magnifier drivers (fwd)

Tesla List wrote:
> 
> >> Subject: Oil filed magnifier drivers
> 
> Subscriber: nikki-at-fastlane-dot-net Tue Dec 31 09:36:54 1996
> Date: Mon, 30 Dec 1996 23:22:18 -0600 (CST)
> From: Bert Pool <nikki-at-fastlane-dot-net>
> To: Tesla List <tesla-at-poodle.pupman-dot-com>
> Subject: Re: Oil filed magnifier drivers (fwd)
> 
> At 03:50 PM 12/30/96 -0700, D. Gowin wrote:
> >
> >fwd Bert Pool
> >
> 
> [snip]
> 
> >> Subject: Oil filed magnifier drivers
> >>
> >> Well, here's our report on the agony of building an oil filled magnifier
> >> driver.  We have spent a couple of months, a couple hundred bucks, and yes,
> >> we did learn a lot, and so here it is so you can learn from our mistakes.
> >>
> 
> [big snip]
> 
> You finished:
> 
> >
> >Son-of-a-bitch Bert,
> >       So are you trying to tell us to stick with
> >the conventional "status quo".]
> >
> >D. Gowin
> >
> >
> 
> Simply "Bert" will do, only my closest friends call me Son-of-a-Bitch Bert :)

I love it! Bert, I've also been called much worse! :^)

<SNIP>

> Every good gambler learns that there are times when you fold your hand and
> walk away. I lost playing this game, so I'm moving to another table.
> 
> I did learn a lot of valuable things from the attempt, and I've shared them
> with the group.  I found that Mylar is a very good h.v. insulator, better
> than I expected.  And I now use brass water faucets and copper tubing with
> brass water hose fittings to make all my h.v., high current tank connections
> - water hose fittings and brass faucets are quick connect/disconnect, very
> cheap, widely available.  To ground my magnifier, I simply screw my coil
> ground fitting onto my real "water faucet" outside, and run the copper
> tubing to the base of my driver coil where I screw it onto another brass
> faucet connected directly to the bottom of the secondary (yes, I actually
> plumb all my connections now!)  I learned that transformer oil which works
> very well at 20 kv performs poorly at several hundred kv, much worse than I
> expected.  And I shared several other small discoveries that I posted in my
> original message.
> 
> If you think the concept of an oil filled magnifier driver is still valid,
> then _you_ should start building some oil filled magnifier drivers yourself
> and push the limits beyond where I took it, or if you'd rather, you can mail
> me some financing for more research on my part ;)  I look forward to posts
> on your research in this area if you decide to venture forth.
> 
> Bert
> 
> 
> Bert Pool
> nikki-at-fastlane-dot-net

Thanks for providing a very well written overview of your various design
approaches/trials. The various strategies you tried certainly made
sense. Similar approaches have been successfully used for high-voltage,
high power resonant transformer designs going up to 3 MV. The question
is how much do you push the envelope, at what cost, and when do you
fold... you guys certainly get an A for effort!! Good luck at the next
table!

FWIW, (for anyone willing to try extending this approach in the future),
Sarjeant and Dollinger (High Power Electronics, Tab Professional and
Reference Books, 1989) have a great section on High Voltage Air Core
Transformers. This chapter is actually misnamed, since the entire
chapter dwells on oil-immersed, high coupling coefficient (0.6+)
transformer design approaches. Controlling E-field stresses by
increasing primary-secondary spacing from the bottom to the top of the
primary, or using other voltage-gradient control measures were the keys.
Also, the use of multiple mylar-oil layers was essential. RTEmp may be a
be better insulating oil than mineral oil for this application. 

However, sometimes simplicity is also the best solution - simple
air-core and larger spacing ala Richard Hull's design!

Anyway... safe coilin' and fruitful researchin' to you, Bert!

-- Bert --