Re: Arc length vs pwr

To: tesla-at-pupman-dot-com
Subject: Re: Arc length vs pwr
From: Mark S Graalman <wb8jkr-at-juno-dot-com>
Date: Mon, 21 Oct 1996 05:38:34 EDT

On Sun, 20 Oct 1996 22:26:08 -0600 Tesla List <tesla-at-poodle.pupman-dot-com>
writes:
>>From MALCOLM-at-directorate.wnp.ac.nzSun Oct 20 22:13:26 1996
>Date: Mon, 21 Oct 1996 09:37:25 +1200
>From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
>To: tesla-at-pupman-dot-com
>Subject: Re: Arc length vs pwr
>
>Hi all,
>
><lotsa snip>
>> >The coupling or K factor is only a ratio of mutual inductance 
>divided 
>> >by
>> >sqrt LpLs.
>> >The ratio indicates the amount of energy transferred. Coupling does 
>
>> >not
>> >create or consume energy. Creation or consumption of energy is only 
>in 
>> >the
>> >primary or secondary circuits.
>> >
>> >Jack C.
>> >Jack,
>> 
>>  That point is understood, I was talking about what the
>> effect to the primary is during its energy release if it
>> is loosely coupled to a secondary coil, or any other load
>> for that matter. I guess my thought was any energy that
>> wasn't transferred to the secondary coil would be returned
>> to the capacitor during the collapse of the primary field. I would 
>think
>> that a ringing primary too loosely
>> coupled to a load or not coupled at all to a load, namely
>> a secondary coil would exhibit extremely high peak voltages and
>> distruction of the capacitor would be ultimately unavoidable. 
>
>>             Mark Graalman
>
>Well that happens on each half cycle of primary ringdown during 
>energy transfer to the secondary. But bearing in mind that unless
>there is an external source of energy from somewhere, Vcp can not
>rise higher than it initially was before the gap fired can it?
>A cap with high ESR will suffer badly from running in an uncoupled 
>circuit as the dielectric heats and possibly hot-spots.
>
>Malcolm 
>
     Malcom,

 The voltage most certainly can rise above the source, if
the primary circuit is viewed from "inside" the loop 
I.E. the capacitor, coil and closed spark gap, the voltage acrossed each
reactance is proportionate to the
current through it. This is series resonance and current is maximum, if
the capacitor has a reactance of lets say
10 ohms and the inductance also 10 ohms (resonance) the
two reactances are of opposite signs so together they
cancel leaving only R losses and the resistance of the
spark gap to limit the discharge current. If the total
non-reactive resistance of the circuit is lets say 5 ohms
(gap and wiring losses) the peak discharge current could
be as high as 2000 amps, now if this 2000 amps is flowing
through our primary capacitor the drop acrossed it could reach 20000
volts with a 10000 volt source. Once that
spark gap fires the charging transformer has nothing to
do wth nothing. I wrote a short article in the TCBA news
a few years back that explains it a little better than I
can go into here, (TCBA news Vol 12, #4 pg. 14-16).

			Mark Graalman