Re: Off Line - DRSSTC (OL-DRSSTC) - 3

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mike" <induction@xxxxxxxxxxx>

Hi Terry,
              Regarding your concern for the 185 UF Buss cap, and 
the ~ 22 amp RMS, can you go to the standard 660 VAC 20 UF caps we 
use in 480 volt input constant voltage filament transformers? Just 
motor starter /run caps really, metal case for getting rid of heat, 
etc. For your value that would be 9.25 caps so a bank of 10 would do 
if they match this service.
Mike


----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, September 27, 2005 8:32 PM
Subject: Off Line - DRSSTC (OL-DRSSTC) - 3


> Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi All,
>
> I have been running a lot of models and now have this for the OL 
> -DRSSTC concept schematic:
>
> http://hot-streamer.com/temp/OL-DRSSTC-03.gif
>
> I had to go to 60BPS instead of 120 BPS.  I use the dead 1/2 cycle 
> to fire the coil so there is no incoming current to quickly recharge 
> the buss cap. Otherwise, once the coil is started, in never turns 
> off!!  The waveforms look like this:
>
> http://hot-streamer.com/temp/OL-DRSSTC-03a.gif
>
> It should put out nice 60BPS bursts with 200kV peaks.  Very long 2mS 
> duration.  Power to the streamer is roughly 1080 watts.  The 
> resonant charger gets the cap up to about 520VDC firing voltage with 
> the line and resistive losses (note that the inductor is 19mH now 
> for 60Hz).  It is a stunning 25 joules per bang!!!
>
> The primary current is only 200 amps and everything else seems 
> generally easy without massive over loads.  The 50 ohm resistors 
> across the gates reduce the gate voltage and act a bit like a dead 
> zone for the IGBT crossover.
>
> The trigger circuit is pretty much out of the SIDAC data sheet...
>
> The only concern is the 185uF buss cap.  It will see about 22A 
> RMS!  That would kill most single electrolytics so I will have to 
> look into that more.
>
> By changing the SIDAC value, it should work off 120VAC or a variac 
> at lower test  voltages too.  Everything can be "fiddled with" as 
> needed to make adjustments or to get it to work.
>
> So it is looking pretty good on paper and by computer.  I think I 
> will order some parts...
>
> Cheers,
>
> Terry