Re: [TCML] RSG disks - who can make them ?

["Chris Swinson" <list@xxxxxxxxxxxxxxxxxxxxxxxxx>]

John,

> Very few coils actually power arc.  Only those rare coils that are  very
> badly designed ever power arc.

It's the same as I think also. It's why I do not class arcing after the 
physcial gap alignment as a factor to be taken into account (assuming the 
coil is built resonably well of course)

> > I think the issues is still there that 1st notch does not work,  when in
> > theory it should work better.  So as 3rd or 4th does...  why is that ?
>
> I'm not sure what you mean when you say that 1st notch quench  doesn't
> work?  Ed Wingate's magnifier quenches at 1st notch at full power  and
> his coil works very well.  Some other folks' coils may be also  quenching

It was a previous post, I can't recall off-hand who said it, but someone 
said generally that coils work better on the 3 or 4th notch and 1st notch 
was found to work worse than 3rd or 4th... that was the reason for my 
comment....

> at first notch too, who knows?

Exactly!


> Most folks have never scoped their
> quenching waveforms !!!!!

I have never done this. Though I dare not run any equipment near my coil, I 
have fried a lot of electronics around the house some meters away form the 
coil even at a few meters range (500W coil)...

In anycase, It would be something I would really like to measure also! See 
what is going on in the real world. I am not sure how to go about it though 
so any clues are most welcome.


> > Something is still missing I think. I like things to add up in  theory and
> in
> > practice... a lot of aspects seem to be a bit  generalised and some points
> > are never really solved and just end up a  matter of general opinion. I
> think
> > the challange of 1st notch quench  is still out there... Though that is 
> > just
> > my own opinion ;-)
>
> I agree that the issues involved in first notch quenching are  worthy
> of further experimentation.


I think its a double problem, first one is dwell time in the gap, BUT, if 
the coil can drain all the energy fast anyway, then the dwell time is 
un-important. however it will not hurt to try to keep it to a low value.

So we just need to know what are the factors, tight coupling for faster 
transfer ? Would less inductance on the secondary make it "easier" for the 
tank energy to transfer into the secondary ?

I know I tried a LOT of coils some years ago. I found that increasing 
inductance to a point works, but increasing it beyond that point is actually 
bad. It could just be that a particular inductance worked best in terms of 
spark gap quench....

I think I documented the results all those years ago (even though I knew 
very little back then) so well worth me taking a second look at my 
figures.... I recall that something like 50 to 100mH was the normal 
"general" figure, though I found something daft like 10mH worked best. When 
I tried 5mH I lost a lot of spark output..

At a guess, the frequency was high, maybe 250khz, though I know I ran up to 
500khz in some tests. Cycle time (frequency) across the gap would be fast, 
though by the sounds of it I could be on the 10th notch by the time the 
spark gap quenches... I concluded at the time that as my tank cap was 10nF 
that it fixed in with 10mH secondary. Maybe to keep all the factors the same 
but progress to 20nF and 20mH.... There is probably no relation between the 
two but I thought it just a little odd that the tank cap size worked with 
the same figure in inductance.

Hopefully in the not too distant future I can plug away at my own confusing 
data and measurements :-)

Chris







cheers

Chris



>
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