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Re: Avalon

Hi Mark,
              I like your thinking - however i would favour a 13M style gap
with 'arms' rather than a rotor as this keeps the rotating mass low while
allowing a very large rotor diameter, which as the electrode speed is pretty
much what determines quenching, is a good thing.  My idea would be a 4 rotor
13M style system - with 2 series pairs each 45º out of phase - you'd only
have to spin them at 7500rpm to get 1000bps and the quenching would be
phenonmenal.

Regards
Nick Field

> Original Poster: "Mark Broker" <broker-at-uwplatt.edu>
>
> Chris, list,
>
> <snip>
>
> > > 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.
>
> <snip>
>
> As someone with a bit of experience with mechanical design, I'd like to
> throw a few comments out there regarding the ARSG (I don't think there's
any
> argument about the type...).  I'd also like to appologize if my
inexperience
> with TCs causes an obviously incorrect assumption ;-)
>
> I've noticed several things about the big TC's spark gaps (mainly the 13M
> and Electrum).  First, 13M uses a sync, and Electrum uses Async.  Second,
> the 13M uses a pressurized (~30psi of Sulfur Hexaflouride) two-break
system
> with electrodes on a 24" Diameter circle.  Electrum uses a series 8 break
> system running at STP in the open air with a 28" diameter electrode
circle.
> The 13M uses a 10HP 3phase motor.  Electrum uses a 15HP 3 phase motor with
a
> variable frequency speed adjustment (a standard approach to vary the speed
> of an AC motor).
>
> Question:  why use so many breaks?  The spark gap is supposed to be one of
> the main sources of loss in the primary system.
>
> Ok, on to Avalon.  I don't think that mounting the tungsten electrodes
> axially on a disk (similar to Electrum) is a good idea:  if a set screw
> isn't tight enough, or loosens over time, you have a catostrophic failure.
> If memory serves correct, a 5 kg electrode would have about 750kJ of
energy
> at 3600RPM on a 24" diameter disk!  I think that electrodes should be
> mounted through the disk near the periphery.  I have a little experience
> with large DC motors (1000+HP!!), and they are HUGE compared to an AC
motor
> with the same torque and HP ratings.
>
> Use fewer disks: only one or two.  Use Aluminum or titanium (MUCH
stronger,
> and expensive, but won't "creep" like aluminum will) disks if a design
like
> Electrum's is to be used.  Otherwise, a G-10, or something similar.
>
> Use a high torque 3phase AC motor, with a variable frequency controller to
> adjust speed, torque, and HP.  I have a little experience with large DC
> motors, and they are HUGE compared to an AC motor with the same torque and
> HP ratings.
>
> In my mind, use a system like Electrum's.  However, use only two G10
disks,
> each with 4 tungsten carbide electrodes mounted through the disk on a 24"
> center-to-center diameter with a total of 4 series breaks.  Design it to
run
> at some unGodly high speed (~7200RPM) using a 25HP, ultra-high torque
3Phase
> motor.  Standard high-speed bearings could be used (American Roller
Bearing
> or Timken).  Mounting horizontally or vertically is something to be
> investigated.
>
> I know that's pretty fast, but a well designed, well balanced rotor system
> will be able to handle the speed.
>
> Please comment....
>
> Mark
>
>
>