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Re: Gap Dwell Times (formerly: Beating Solved)
Tesla List wrote:
>
> > Subject: Re: Gap Dwell Times (formerly: Beating Solved)
>
> >From sgreiner-at-mail.wwnet-dot-comTue Oct 1 21:51:08 1996
> Date: Mon, 30 Sep 1996 14:50:17 -0700
> From: Skip Greiner <sgreiner-at-mail.wwnet-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Gap Dwell Times (formerly: Beating Solved)
>
> Tesla List wrote:
> >
> > >From MALCOLM-at-directorate.wnp.ac.nzThu Sep 26 22:18:09 1996
> > Date: Fri, 27 Sep 1996 08:13:59 +1200
> > From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> > To: tesla-at-pupman-dot-com
> > Subject: Re: Gap Dwell Times (formerly: Beating Solved)
> >
> > In reply...
> >
> > > I did some research this weekend, pouring through a Corum brothers
> > > monograph and some old posts to this newsgroup and found out that the
> > > optimal dwell is 1/(k*Fr), *not* 1/(2*k*Fr). In other words, the spark
> > > gap should conduct for only 1/2 of the superimposed beat-frequency
> > > envelope. Primary current peaks at that point, and maximum energy is
> > > transferred into the secondary.
> >
> > I started from k approx dF/F, and ringup time = 1/2dF so you can see
> > how I derived that. The problem when cutting the gap off (if you
> > could) when Ip is maximum is that with k<1, most of the primary
> > energy is coupled to the primary. I tried doing exactly this with the
> > MOSFET gap and the spikes hit the roof. Virtually none of that energy
> > was coupled to the secondary. The spikes in a real gap would have re-
> > ignited it anyway. I wonder if they have actually tried doing this?
> > I found the ideal dwell to be when the secondary was fully rung-up
> > and the primary had virtually nothing left. Even then, quenching at a
> > primary zero-crossing is a no-no because of spike generation. I sent
> > some photos I took of this process to several people.
> >
> > Malcolm
>
> Hi Malcolm and all
>
> This is an extremely interesting thread. I am now getting confused.
> Exactly what do you mean when you say that the secondary was fully rung
> up? Is this when you believe that all of the energy is fully transferred
> to the secondary from the primary? If so, how can you tell?
>
> Thanks
>
> Skip
Skip,
I can't speak for Malcolm's interpretation, but a system is normally
considered fully rung up at the first maximum of the damped resonant
wave. It is rung down at the end of the wave train of damped
oscillations.
A lot of folks think the primary rings are transferred to the secondary!
Well,.... yes and no. If you do not quench your primary circuit arc
quickly enough, yes! If you quench the arc at the first zero crossing of
the primary volatge peak, no!
Remember that the primary is a complete resonant circuit all by itself.
The secondary is also a complete and separate resonant circuit unique to
itself.
Ideally, we want to dump the magnetic energy we have expanded out from
the primary winding into the secondary. But, before the secondary has a
chance to "talk back" or do an "inductive dance" with the primary, we
want the primary circuit OPEN (it doesn't exisit as a current carrying
path anymore) That is, there no longer exists a ringing in the primary
circuit. The magnetic energy we sent out from the capacitor blast, now
falls in on the secondary and the secondary is absolutely free to ring up
and down without the primary system interacting with it in any way.
This is ideal action according to a number of theoretical approaches as
well as the Corums. The spectral purity of the secondary is preserved.
I am not 100% convinced that this gives best spark. I am convinced this
gives the best RF wave.
Richard Hull, TCBOR