Re: OLTC update

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Jumping in ahead of Terry here...

In the typical TC where you're feeding the tank with a high impedance AC
source (i.e. a NST ), then you put the gap across the transformer to serve
as a safety gap, with the primary C charging through the primary L, and the
voltage source shorting during the spark.  Fortunately, the source is
current limited (by design), and the spark doesn't last very long (low DC),
and you don't really want to start trying to recharge the C during the
"bang" anyway.

In Terry's design, it's more of a resonant charger from a DC source, so you
need to have the primary C fed through an inductor from a fairly stiff (low
impedance) source.

Tesla list wrote:
> 
> Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Gary.Lau-at-hp-dot-com>
> 
> Hi Terry:
> 
> I noticed that contrary to the practice with spark gap coils, you are
> placing the power supply across the tank cap, rather than the "gap".  This
> places a more difficult burden on the filter network between the tank and
> the power supply, to keep the RF out of your mains.  Have you examined the
> signals going back to the mains?  I see the obvious problem with placing
> the power supply across the gap - a turn-on fault will short out the power
> supply and smoke will flow...  Maybe a lower current IGBT could be placed
> in series with the PS, breaking the connection whenever the main gap IGBT's
> are told to turn on?
> 
> Also, with the distributed tank cap/IGBT concept, I assume you plan to have
> a separate decoupling network/filter for each segment?
> 
> Regards, Gary
> 
> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> 
> Hi All,
> 
> Today I made a fairly accurate MicroSim Model of the OLTC:
> http://hot-streamer-dot-com/temp/OLTCigbtC-8-13-01.gif
> http://hot-streamer-dot-com/temp/OLTCigbtC-8-13-02.gif
> I change a few component values in the controller between the LM311 and the
> LMC555 for better control:
> http://hot-streamer-dot-com/temp/OLTCigbtC-8-13-03.gif
> 
> Cheers,
> 
>         Terry