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Re: Avalon

>Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net>
>
>Hi Chris,
>
>My "meat" is interspersed.

mmmmmmm beefy :)


>
> > Original Poster: "Christopher Boden" <chrisboden-at-hotmail-dot-com>
>
> > 1. Should the system be AC or DC? Why?
>
>For a coil THIS size, I would go for DC. Why? Two reasons:
>You can run three phase power, which means less current
>draw per phase (smaller wiring, more practical, "easier" to
>fuse AND switch properly). Secondly, you can run an ASRSG,
>by which means you can control the power, which you feed
>the coil, by varying the breakrate. Power control =>> easy
>=>> ;o)). Finding diodes that will handle your power might be
>a problem, I donīt know. Of course, you will need to design
>a charging reactor to limit the inrush current (cap and diode
>death).
>

Reactor design? Alright...now's where one of you Mathemagictians get to do 
your thing.


> > 3. Primary type? (I am thinking interior helical like Electrum, but is
> >here a better way?) I would like to be able to change tuneing
> >without too much hassle.
>
>For this kind of power, I donīt think you NEED a helical coil.
>A flat one would be more than adequate. Donīt know why
>Greg went for the helical coil. I would do tuning off axis. I.e.:
>a big tuning coil (easy to build) during building. After you have
>the final setup, make a "fitting" primary with small adjustment
>possibilities. I wouldnīt worry about "ease" too much. Once
>you are set, you wonīt be changing it much anyway.

I think a large flat spiral made of 1" or bigger Cu pipe might be fun. 
Mounted on a UHMW form. Ribbon woud be cool, but I don't want to fight 
breakout from the edges.


>
> > 5. Power source? I am thinking 200 - 250 kVA from a large
> >pig, or pig array,  powered from 240 or 480 at high amperages.
>
>A single phase pig with 250kVA running on 240v would be (I
>think) a hard-to-find item and it would be crazy. At 250kVA and
>240V you would need at LEAST 1300 amps supply. This is for
>a cos phi of 0.8, which I doubt transformers in that class can
>achieve. Go for 3 phase 660V setup.

Can we GET 660V in the US? 3 phase is easy, and 120-240-277(high freq mostly 
for industrial lighting)-and 480 are easy...but 660 is new to me.

Much lower amperage
>per phase and much easier to handle. You can run your ASRSG
>on 3 phase, too. A 3 phase power frequency converter could
>be used to change the rotating speed (induction motor) of the
>gap. Plan on using a 25-30 hp motor for that gap

I'm thinking a large DC forklift motor, easily adjustable and very strong.

and DESIGN
>it well. The G-forces on a the big (necessary) disk are almost
>unimaginably high. Take material growth (due to heat) into
>account.

I am thinging balanced and turned aluminum disks, 12" dia and 2"thick at the 
center tapering to 3/4" at the edges. Drilled and tapped for 1/2" electrodes 
with dual set screws for each electrode. Possibly turned concentric grooves 
in the disks for cooling.

>
> > 6. Control system?
>
>Very little bells and whistles. Multiple safety circuits, including
>temperature monitoring, etc. Amps, volts, speed control,
>interlock relays, DUAL (!!) SAFETY KEY. Best bet would be
>to use dual operator control, i.e.: make it IMPOSSIBLE to fire
>the coil alone. Remember you WANT (actually your life WILL
>depend on it) total control, NOT good looks. The ahhs and oohs
>should come from a working coil, NOT a cool-looking control
>cabinet that takes a half an hour to find the off switch.
>

My dad hammered something into me from birth, Form Follows Function, make it 
WORK safe, then make it pretty.


> > 8 Gap type? I like the Electrum gap best as far as design,
> > I am thnking of  something similar. 10 Gap series rotary?
>
>ASRSG, number of gaps would depend on processing power.
>
> > I would like to have the maximum amount of flexibility in operation of
> >the coil. Variable tuning, single shot modes, variable spark gap
> >speed...etc. I would like to have an ASync spark gap that we can
> >lock on with a tach or computer control to be sync. This isn;t just
> >for pretty, I would like it to be a research tool to better the state
> >of the art in Tesla Coil design.
>
>Most of this can be included in the control cabinet. I would build
>the control unit, so that you can fire in a "sure mode". Make a
>secondary cabinet, with add-ons, which can be plugged into the
>primary control circuit to add these variables. Do NOT build all
>of it into one cabinet. The main control cabinet MUST be neat and
>anyone should be able to find the important controls in the worst
>case FAST. Make your control cabinet, so that you MUST switch
>off lights manually, but they automatically come back on, once
>power is cut OR a failure occurs.
>





> > 9. Cap type and size? Or should I call the Corona Bottleing
> >company....lol > :) just kidding.
>
>Theoretically, you could build an MMC. I would go for the MMC
>technique, but use Maxwell, etc caps instead of MCs. The name
>for this would be MBPCA ;o)) (Multiple Big Pulse Cap Array). If
>you plan on building beer bottle caps, you had better BUY a
>brewery AND a company that recycles old glass (parts) ;o)))
>Sorry, but I just couldnīt resist that one. Maxwell could custom
>design a cap (array) for you. Aerovox is another company,
>which I have found to be VERY helpfull and informative.
>

I'll be contacting them this week about sponsorship



>More thoughts: run your lights from a two DIFFERENT supply
>sources. (not counting the TC power input). There is nothing worse
>than HV and darkness ;o((((. Plan an emergency exit and post it so
>that ALL can see and find their way out. Make an automated fire
>extinguisher system around all power parts (xformer, rsg, cap,
>etc). Install some turbo fans that can exhaust fumes, etc.  fast, if it
>should ever be necessary. There is nothing worse than bad
>publicity. Make a HEAVY (twice the necessary size) duty grounding
>system. This will require a lot of earth work.  Be prepared to see
>around 1.5-2kA (!!!) peak current in your grounding path. You DONīT
>want that to go astray. Place the xformer, the caps and the RSG
>in shatter proof "containers". If any of these blow, you want to
>contain the hazard to one area and not have it spread around.
>

The HV systems will be housed in a seperate room, a secure environment with 
incredible ventillation. It will have keyed access, and PIR motion sensors, 
the door will not lock to the inside, and the coil will shutdown if there is 
movement in the room.




>BTW: Thanks for putting me in the league with the big dawgs. I donīt
>think I deserve that ;o)) I DO have some knowledge on coils. Some
>of which has been "calculated and tested", the rest is based on not
>so scientific methods (like trial and error ;o)). However, I have NO
>experience with coils anywhere as large as you are planning. Most
>likely, I wont be able to make it, due to lack of money and the fact
>that I am training into a new job field (very limited time; even for my
>own hobbies). However, I can provide assistance per e-mail or
>phone, if that is of any help. I would try to make it over on the *BIG*
>day, of course ;o)) My phone number is 049 for Germany, 6425 (area
>code) and 8210075 (actual number).
>

Got it :)

>If any of the coilers on this list ever come over to Germany, they
>are (of course!!)  more than welcome to come over and stay a
>few days (weeks, etc ;o)). It would be most enjoyable ;o))
>
>Coiler greets from Germany,
>Reinhard

You're on the team :)

Have fun!

Chris Boden
The Geek Group
www.geekgroup-dot-org
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