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Re: Very weak coupling and life of primary arc



In a message dated 99-09-24 08:09:53 EDT, you write:

<< 
> Hi Terry,All,
> I'm interested in the correctness of one claim that
> concerns weak prim/sec coupling and lasting of prim.
> gap arc.
> If k is very low (read k< 0.1) it is claimed that
> after all the energy is completely transferred to
> secondary circuit for the first time,primary arc turns
> off and doesn't refire again.
> In other words this is a case where there's no return
> of energy from secondary way back to primary.
> Relatively small induced voltage across Lp by mag.
> influence of secondary is found to be a reason (which
> is understandable since small k).
> However ,I doubt.The gap should lost its conductive
> properties in 1 microsec. itself!
> It is emphasized: no need of any rotary
> ,cooling,forced air flow in gap if input power isn't
> to considerable (1 KW aprox.limit)-just static gap
> employed.
> Maybe it would work if multiple series gap used?
> And yes, just for any case -the protection of power
> transformer is a must here.
 
> Every experience/info/thoughts on this subject is
> welcome.
 
> -Boris
   >>

Boris,

It is true that the energy transfer will be one way, from primary
to secondary with loose coupling.  But it will not occur in 1uS.  Rather
it will take the amount of time for one complete beat, which could be 
10 RF cycles or so.  The transfer of energy is gradual, and usually 
takes a number of RF cycles.  The number of cycles depends on the
degree of coupling.

With loose coupling the energy does not transfer faster; it actually
transfers more slowly.  If the coupling is tight, the energy will transfer
faster, but there's the likelihood that the gap will not quench at that
point, and the energy will be able to reflect back to the primary.  For
this reason, the total time that the gap is ignited may be approximately
equal with either loose or tight coupling.

The real way to extinquish the gap quickly is to make sure the TC is
well tuned and is heavily loaded by output streamers which will suck
the energy out the the system quickly, and permit the gap to quench.

Cheers,
John Freau>