Re: GB> Chaffee Spark Gap

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

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

Tesla list wrote:

> Original poster: "Wells Campbell by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <wellscampbell-at-onebox-dot-com>

> could you run down a couple of things to a non-expert? like describe
> basically what a poulson arc is and does, is it similar to a quench
> gap?

	If the terms are used accurately, they are utterly different.
	(properly used a spark is a very different thing from an arc.)

	An arc (a Pulse is a specific type, runs in a mag field and an
	alcohol vapor atmosphere, IIR....) has (essentially) continuous
	conduction.  Since it has a negative resistance (yes, really), it
	can function as a sport of amplifier.  If surrounded with
	a resonant circuit, it can generate oscillations, more or less
	CW (ok, noisy by modern standards....).  On could build a TC
	type device, analagous to a VTTC, with an arc as the active
	element.  For a decade or so, arcs could handle more power than
	vacuum tubes, were used for early code & voice.

	All spark gaps are more or less 'quenched', in that current
	flow is NOT continuous, tho the interruptions may be brief.
	A spark rig with an arc across the points is, by definition,
	malfunctioning.  The term 'quenched gap', as commonly used,
	refers to a specific type of gap, with better than average
	quenching.

> And the probable environment in the gap in the article? It said moist
> hydrogen in nitrogen, if I remember correctly? Is that at sea level
> pressure, or more, or less? what would be purity concerns, (besides
> eliminating the o2!)

> Would the alcohol vapor have to be pure alcohol, or would this too be
> in nitrogen? Could you "prime" such a gap by running a spark through
> alcohol and air with an outlet hole and burn off the 02, then seal it
> and run it? It seems that if small enough a cavity is made, then the
> amount of alcohol needed would be very small (teaspoon at a time)?
 
> ---- "Tesla list" <tesla-at-pupman-dot-com> wrote:
> > Original poster: "Mike Nolley by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > <nolleym-at-willamette.edu>

> > >Originally the gap was run in an atmosphere of moist hydrogen,
> > >but hydrogen being difficult to obtain in ordinary practice, it
>>> was found by Cutting and Washington that alcohol vapor could be
>>> substituted, provided it was distilled into the gap

> > Sounds a little like the Poulsen Arc, except the electrodes are
> >aluminum and copper.

> > Fairly little research has been done on this list with regard to using
> > hydrogen gas or alchohol vapor as a quenching medium.

	Arcs don't quench, generally.

>>  This is due to the danger of using flammable gases.  Methinks however
>>that this concern pales in comparison with the dangers of hv.

	Concur.  Sort of.  AND the dangers of flammable oils in caps...

	best
	dwp