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Re: 250watt solid-state flybacks? (fwd)



---------- Forwarded message ----------
Date: Wed, 13 Oct 1999 14:35:49 +1000
From: davidhosking <davidhosking-at-bigpond-dot-com>
To: Dale Hall <Dale.Hall-at-trw-dot-com>
Cc: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: 250watt solid-state flybacks?

Thanx for the info Dale,
Very impressive results for such a low power input!

I could probably get the visual effect I want (I.e. People say :- WOW Whats
That???)
with about 5-10 sparks/sec.
 Spark length 6 to 8 inches with multiple breakouts using small discharge
points
As I intend to mount it on a helmet I want to produce short bright sparks/
Corona.
I would use a small cap for rapid charging/firing.
How small is the spark gap you are using in the primary circuit ?
I need to make
the primary circuit small enough to fit on the helmet.
Are you using any special flyback circuit or the standard one transistor or
2 transistor circuit
that people use for powering plasma bulbs?
ringing choke circuit
Thanx again,
David Hosking
----- Original Message -----
From: Dale Hall <Dale.Hall-at-trw-dot-com>
To: <davidhosking-at-bigpond-dot-com>
Sent: Wednesday, October 13, 1999 4:31 AM
Subject: 250watt solid-state flybacks?


> David,
> If you could accept a lower bang rate....
> My DC TC design runs from a 12v Nicad consuming <1W (will run from a 9v
> alkaline at some perf loss)
> It will power arc 20" reliable (every time) across a glass to air
interface,
> or 28" max but less frequently.
> A more robust flyback design with discontinuous mode to conserve battery
> power when Cap is fully charged
> (charge maintenance mode) could be developed. So ~ 10 bangs / sec for ~
> 10Wpk ???? maybe
>
> My DCTC:
> 12v (~1watt, 40ma charged, 150ma peak at begin of cap charge) power to
> flyback generating ~`7kV dc
> Charges .1uF mylar cap with time constant = 1 sec so 3sec = nom 7 sec =max
> (C*V^2/2 = 2.45J/bang)
>    you need a BIG cap ie lots of capacitance to make up for the low break
> rate.
> Pri 1/4" frig tubing spiral =~6.7uHy, Sec= 6.25D x 20" H  #24awg on pvc
> L=28mHy k=.18  Vsev ~350-420kV
> Ctop ~25pF  8"x24" galvanized (4ea 90degree heating elbows - home depot
> ~$16total)
> Discharge point to point power arc = 28" best record to date. (air / glass
> dielectric for 2 dimension restriction)
>
> photo's/scope shots enclosed, any questions ?
>
> Dale
> Redondo Beach, CA
>