Re: Protecting NSTs + Thor project status

Tesla List <tesla-at-pupman-dot-com> on 27.09.99 11:44:03

To:   tesla-at-pupman-dot-com
cc:    (bcc: Marco Denicolai/MARTIS)
Subject:  Re: Protecting NSTs

>Original Poster: "Malcolm Watts" <malcolm.watts-at-wnp.ac.nz>
>> Original Poster: "Marco Denicolai" <Marco.Denicolai-at-tellabs.fi>
>> Hello.
>> If with "fullwave" you mean a bridge (4 diodes), actually a single
>> series diode is enough.
>Indeed I did mean a fullwave bridge. All the  NSTs I've seen have a
>centre-tap in the secondary. I don't know how you'd get a fullwave
>output from anything using a single diode?

Of course you need the full-bridge to get a DC, then I though you have a
filtering tank capacitor. So I understood the question was to avoid resonant
charging and to avoid to discharge all your power supply tank capacitor through
the spark gap. Then you need one more series diode and a series inductor.
Probably the NST magnetic shunt replaces that inductor but you still need the

>> What is the maximum quench time of the spark gap used? That could be
>> so fast to limit by itself the current rise at the transformer side.
>?  Not sure how this relates.

Probably I was wrong assuming that you have the big capacitor filtering
your DC.
Without that it surely doesn't relate.

>How's the quasi-resonant supply going? I've just resumed work on
>my DC charger also.

Prototype ready and working, final version's PCBs ready, assembling the final
version into a decent 19" rack (9U high!). See the rack picture at

If all that stuff works, I though I could make public schematics and PCB layout
to everybody.

The only open problem is spikes from the power supply output getting back
to the
drivers and killing some driver IC. That happens after some minutes of
continuous run.
I am not so worried about that because my "runs" up to now have been with
just a
capacitor and spark gap series as a load (no primary inductance). I hope that
the presence of the primary coil, dropping down the ringing frequency to 50 -
100 kHz, will reduce the damaging spikes induced back to the driver.

Let's see...