Re: Triggered Spark gap triac question

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

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

Tesla list wrote:
> 
> Original poster: "Darin Willson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <darinwil-at-wmt.dnsq-dot-org>
> 
> I went to the electronics store and bought
> a triac to replace the one in my dimmer
> for this setup, being the type of person
> that I am I just looked for a 25A triac and
> bought it (they only had the type that I bought
> at that amp rating)
> When I got it I looked up the one that Mark used
> and found that his is rated for 600V and mine is
> only 200V , Is this going to be a big deal?
> 
> Thanks
> Darin

-- 
Bert Hickman
Stoneridge Engineering
"Electromagically" (TM) Shrunken Coins!
http://www.teslamania-dot-com