Re: SISG Test Procedure

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Paul Benham" <paulb@xxxxxxxxxxxxxxxxxxxx>

Hi Mark,

How about modifying the circuit so that it has a trigger input or on board
oscillator?

Cheers,

Paul.

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Thursday, June 01, 2006 3:08 AM
Subject: RE: SISG Test Procedure


> Original poster: "DAVID BAILEY" <psigraphics@xxxxxxxxxxx>
>
> Wrap liquid Nitrogen around the coil in a tube.
>
>
> >From: "Tesla list" <tesla@xxxxxxxxxx>
> >To: tesla@xxxxxxxxxx
> >Subject: SISG Test Procedure
> >Date: Wed, 31 May 2006 16:14:21 -0600
> >
> >Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>
> >
> >
> >All:
> >
> >I am getting ready to test the SISG concept on a full size coil and just
> >realized that my test plan is flawed.  I need some help to set up the
> >test so I don't blow things up out of the box.
> >
> >The coil is 4.5" OD X 27" lg with a John Freau Toroid resonates at
> >around 150Khz.  The primary is flat and tapped at about 9 to 10 turns to
> >resonate similarly with a 36 nF MMC(previously was 38 nF homemade
> >parallel plate cap).
> >
> >The important details are that it is uses DC resonant charging with a
> >bank of (4) MOTS wired parallel(2 anti-parallel) on the primary and the
> >secondaries in series followed by a full wave rectifier feeding filter
> >capacitors to reduce ripple to 1000 vdc.  A 31H charging reactor
> >followed by a blocking diode charges the tank capacitor.
> >
> >I current limit the MOT power supply with an additional MOT(secondary
> >removed primary reduced to 60 turns) that is gapped between the I and E
> >cores.  A .040" gap gives me 16 mH which current limits the power supply
> >at about 17 amps.
> >
> >Spark Gap is an RSG running at 460 bps which is about the max allowable
> >for the power supply to re-charge the cap between bangs.
> >
> >Here is the problem.  I want to start out with the SISG running at a low
> >BPS and then bring it up in stages.  This way I can collect data and
> >analyze as I go.  Specifically, one of the concerns will be IGBT
> >heating/cooling.  Originally, I thought that I would adjust the current
> >limiter(by reducing the gap) thus de-rating the power supply and that
> >this would drop the SISG BPS because the cap would charge slower between
> >bang.
> >
> >I now think that this is wrong because it is the filter caps that charge
> >the tank cap thru the charging reactor resonating with the tank cap.
> >Thus, my plan will cause the process to start with the filter caps fully
> >charged and the SISG will take-off at 460 BPS.  Since the power supply
> >will not keep up due to current limiting, the filter caps will gradually
> >discharge and the BPS will drop until the threshold voltage is not
> >attainable and the SISG will stop firing.  Nothing like an
> >unsteady-state test method.
> >
> >It seems that I need to increase the inductance of the charging
> >reactor(and leave the current limiter alone).  Problem is a charging
> >reactor inductance of 100H will only get me down to 150 BPS and where am
> >I going to get another 70H over my 31H that I have.
> >
> >Can anyone follow my babbling and suggest an alternative approach that
> >can get the BPS down for the initial testing without abandoning the DC
> >resonant charging.
> >
> >Thanks
> >
> >Mark Dunn
> >
>
>