Re: Triggered gaps vs Sync rotary

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

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

In a message dated 7/24/02 1:48:47 PM Eastern Daylight Time, tesla-at-pupman-dot-com
writes:

Jim,

Good point about the soaring losses at higher powers.  I hadn't 
thought of that, and I don't think anyone mentioned it in the past
during the triggered gap discussions.  Perhaps a triggered 
gap may never be very efficient for large coils, unless some radical
improvement can be thought of.  

Cheers,
John


>
> jimlux-at-earthlink-dot-net>
>
> > >
> > > One wonders why the SRSG seems to have better performance?  What aspect
> of
> > > the triggered gap is the problem? On-resistance? Quenching?
> >
> > I got the same spark length with a triggered gap and with a
> > SRSG on my TT-42 TC, at about 700 watts.  I suspect that
> > at higher powers, the triggered gaps have poor quenching,
> > or may heat up and misfire, etc., unless they have some
> > sort of cooling/quenching airblast, such as a typical static
> > gap would probably require.
> >
>
> I was thinking that while an air blast can fix the quenching and cooling,
> with a triggered gap, you're still looking at a longer arc path (since it
> has to be long enough to hold off the primary voltage before firing).  A
> rotary can have a very short gap for the time while the arc is burning (and,
> in fact, probably actually gets shorter during the arc, as the electrodes
> come closer to each other).
>
> A few extra hundred volts drop in the gap could have a very large effect on
> overall efficiency, particularly for a high powered coil where the primary
> current is high.  In a 1000A arc, the voltage drop is something along the
> lines of 10kV/meter (or 100 V/cm), and for the probably much lower currents
> in a TC, the drop is probably higher.
>
>
>
>