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replacing the spark gap with SCRs



Original poster: "eahab el naga" <tesla.dude-at-gmail-dot-com> 

I finally got two huge SCRs necessary to handle the current needed for
the capacitive discharge. I also came up with a schematic that will
the fire the SCR's (which are opposing kind running like a triac) at
the peaks of the sine wave. I am letting the circuit ring 5 times then
wait for the next peak in the sine wave. The SCRs i got are 1800V
1000A puk style and can handle 17000 amps repetative pulse for 10ms
each. I really think that i could pull it off..however i am probably
going to double the SCR's before i run full power through it
(hopefully i'd be able to find a 1kv transformer for several kw)
meanwhile i am going to rectify 440volts through a transformer i have
and have a capacitor to smooth followed by chokes to the tank
capacitor (not sure about my terminology but i'm refering to the one
in the LC circuit).
I'd like to know how to possibly improve the design and if there are
any flaws in this concept. I plan on testing the cuircuit with just 12
volts on it and have a scope monitor it from a few turns of coil
placed in the center where the secondary would normally be. If this
works i am hopeing to get a dramatic increase in effeciency but i came
across a few thoughts:
1) the secondary current would be way too high and instead of getting
long streamers i'd get short intense ones because the primary voltage
is low (kinda like the effects of a solid state tesla coil)
2) to lower the current rise, I would increase the number of turns of
the primary inorder to ease the stress on the SCR's and allow them all
to turn on before the high current pulse is sent through them(keeping
in mind that i'll be paralling them once i get 4 SCRs),but would that
make problem number one more significant.
3) because of the lower primary voltage, can i make the winding closer
to the secondary as long as they don't rise too much in order to raise
the coupling coeffecient

anyways this has a long, long way to go but i plan to have this
actually done within 2 weeks.

by the way, i also have smaller SCRs that are also puk style that i
hope to use on a table top tesla coil one day if this ever works out.

thanks a buch,
Eahab El Naga

my old, old site: http://eahab1.port5-dot-com