Re: Triggered Spark gap triac question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Darin Willson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <darinwil-at-wmt.dnsq-dot-org>

Well I must be lucky as since I couldnt return them anyways
I threw them in and boy it works alot better! This comes
to my next question/observation. Im using two of the
Triggered gap power supplies in parallel to power a small
coil and when I hooked it all up no change in performance!?!
Then I got to thinking Ive asked before the output of such
a power supply and people have said anywhere between 25Kv-50Kv
and I thought to myself finally I must be overvolting my cap!
I have a partycup cap and If I set the SG small enough so that
it fires I only get about 1 1/2" arcs to a grounded wire If I 
widen the cap any it just stops firing and this seems kinda weird
as directly off the power supply I can arc gaps of about 2"!

Does this sound like what is happining?

Thanks 
Darin


9/5/2002 9:00:09 PM, "Tesla list" <tesla-at-pupman-dot-com> wrote:

>Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<bert.hickman-at-aquila-dot-net>
>
>Darin,
>
>Unfortunately, it will likely be a problem if your TRIAC is truly a 200
>volt device. Some electronics store chains will re-mark higher voltage
>devices and sell them as lower voltage devices (with proprietary
>brand/markings) in order to use up inventory surpluses and "broaden"
>their product offering.   
>
>The capacitor that's in series with the ignition coil can store as much
>as 1.4 times the RMS line voltage when the TRIAC fires. On the NEXT half
>cycle of incoming line voltage,  the capacitor's stored voltage "adds"
>to the incoming voltage, resulting in a stress of as much as 2.8X the
>incoming RMS voltage being applied across the TRIAC before the next
>firing. If you are applying 120 volts AC off the mains, the TRIAC will
>need to be able to safely hold off over 330 volts. A 400 volt TRIAC is
>probably the minimum rating you should use for this application. 
>
>Best regards.
>
>-- Bert --
>--
>Bert Hickman
>Stoneridge Engineering
>"Electromagically" (TM) Shrunken Coins!
>http://www.teslamania-dot-com
>
>
<snip>