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Re: Thyratron pair (was DC Drive)
---------- Forwarded message ----------
Date: Wed, 15 Oct 1997 00:09:40 -0400 (EDT)
From: richard hull <rhull-at-richmond.infi-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Thyratron pair (was DC Drive)
>>Malcolm
>
>No, fast pulse rise time is basically related to switch turn on time.
>Spark Gaps and H2 Thyratrons turn on in a few nanoseconds, some newer
>fast tubes in the 10's of nS, IGBTs in the low 100s nS and older vacuum
>tubes much slower. Secondarily, low surge impedance may slow rise time
>a bit, but fast switch turn on time is most important.
>
>The faster the rise time the more the wave form resembles a square wave
>and there are multiple odd harmonics available for the resonator to
>use. There is a danger in having too fast of a rise time with a very
>narrow pulse as the resonator is unable to use the fequency content of
>the pulse.
>
>So, while rapid rise time is important, driver dwell time and frequency
>content during on time are also important considerations. Frequency
>content of the driving pulse that matches frequency requirements of the
>resonator is crucial and probably represents a great deal of energy
>transfer to the resonator.
>
>
>
>RWW
>
>Richard Wall is correct in the above by my observations to date. You can
definitely quench too fast even at k=.66!!! Spark gaps appear way too slow
and H2 Thyratrons appear a bit fast. Faster is better than slower if you
are building a very tightly coupled, small table top maggey system with a
natural higher frequency than the big jobs. I don't think an H2 thyratron
could compete with series quench rotaries in k=.45 coupled maggeys of 100khz
or lower frequencies in the 10KW power class. (they are just too quick)
Richard Hull, TCBOR
>