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Re: New to list, a few questions



Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ludev-at-videotron.ca>

Hi Sean,

For the refresher course check:

HTTP://www.tpub-dot-com/neets/

For your high speed rotary spark gap: you deal with electrical
phenomena that happen really fast you charge your cap in AROUND
half a half cycle 1/240 second ( 4.167 millisecond ) but the cap
discharge is really faster; take a typical tesla coil with a
resonant frequency of 200 kilohertz, when the cap discharge it'll
oscillate at this frequency and it'll take AROUND 10 cycle for
the primary to transfer his energy to the secondary if no
discharge happen this transfer of energy will go back and forth
until no energy remain. Many people think that a well design coil
need to quench at first notch ( after 10 cycles in our example )
Many think that you need to force the gap to quench but other
like me think the best way to quench a gap at first notch is to
have a streamer from your coil happen at this moment ( the energy
go in the streamer and the gap quench because no energy remain in
the circuit ). OK back to your rotary, 200 kHz * 10 cycle = 50
microsecond, you have a rotary turning at 34000 rpm you put your
electrode at 10 inches of the center ( need to have a solid
disk!!! ;-))  ) that mean that your electrode travel at 567
inches by second but they only travel .02835 inch in the 10
cycles of the first notch ....

Rotary gap are useful for force the cap to charge a precise
amount time before the discharge and they are useful for
preventing a gap to power arc ( ex: if your transformer is to big
for your caps or your gap is less than optimal the power from
your supply will discharge in de spark gap instead of recharging
your cap ) But they are useless for force quenching.


Cheers,

Luc Benard    

Tesla list wrote:
> 
> Original poster: "Sean Kinkade by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <thopter-at-earthlink-dot-net>
> 
>   Hello all,
> 
> I am about to construct my first coil but I am so new to this that I
decided to
> unsubscribe to this list shortly after I subscribed since I figured I
wouldn't
> understand what was being discussed.  Evidently unsubscribing didn't work, so
> here I am.  I guess I'll stay on the list.
> 
> I've been reading and researching as much as possible on the Internet about
> TC's so I'd have a decent understanding about them before I dove in and built
> one.   I have forgotten 90% of all the basic electronics I learned 13
years ago
> as a bio-med equipment repairman in the Army so I'm needing a good basic
> electronics refresher course.  Anyone know of a free or cheap tutorial
program
> available?  My main weakness is the topic of capacitance, pretty important
> here!
> 
> What I lack in electrical knowledge I make up for in mechanical design
> knowledge so I shouldn't have any trouble with the hardware aspect of
coiling.
> I have a 9" metal lathe and a medium size milling machine in my garage
plus an
> excellent CAD program on my computer so I can machine any custom parts I
need.
> I also live in the greater Orlando, Florida area and we have a surplus store
> here to die for called Skycraft.  They have everything electronic and
> mechanical there and I do mean everything....but they were sold out of neon
> sign transformers!  That's something I still have to find.
> 
> Now, a few questions:
> 
> 1) Is there any physical limitation to a rotary spark gap if the mechanical
> aspects of it were theoretically unlimited?
> 
> I have a brushless D.C. motor ( approx. .5 HP) that produces 5,300 RPM per
> volt. It is from Germany and used for R/C airplanes.
> It can safely handle a 9.6 volt 2400 mah power supply which means it spins at
> 50,880 RPM with no load.    Even geared down 4 to one for torque this could
> possibly spin the rotary spark gap at over 12,000 RPM.   I'm confident I
could
> machine a spark disc that would not fly apart at this speed.   If I had to I
> could even built an engine powered rotary spark gap device using a 1 HP
R/C car
> engine.  Output of the car engine is 34,000 RPM with laod applied.  It
would be
> noisy but boy would it rev up.
> 
> 2) What effect does a higher frequency spark gap produce?   What is the
highest
> resonant frequency anyone has ever heard of anyone producing with a Tesla
coil?
> 
> 3)  I hope I'm not a heretic among heretics when I say that I am getting into
> this field to explore possible levitation effects on matter.
> 
> 4)  Has anyone on this list ever experimented with mixing different forms of
> energy
> such as operating TC's in the vicinity of Van de Graaf machines,  running
> multiple TC's in close proximity with different frequency spark gaps, playing
> with lasers or microwaves in the vicinity of TC's?
> 
> 5)  Has anyone ever designed a rotating Tesla coil?  What would happen (if
> anything) if the unit spun around the secondary coil axis at a high rpm?   A
> rotary spark gap could be designed to be co-axial for this configuration.
> Or....would anything interesting happen if the TC unit remained
stationary but
> the grounding point were disc mounted and spun around the secondary coil
with a
> rotary contact?  Would a sheath of discharge surround the toroid?
> 
> I have the plans for BTC-5 from Information Unlimited but that baby is a
> monster so I ordered the plans for BTC-4 and will make the it my first coil
> project.  I'll build the BTC-5 next year.
> 
> Thanks for any constructive replies.
> 
> Sean
> 
> 
>