RE: [TCML] DRSSTC RF cycles

[Justin B <boshjack@xxxxxxxxxxx>]

Yes, it's a fun mess. I just have to keep on tuning. Sadly my system isn't built for coupling adjustment. right now the first primary turn is about 1"below the first secondary turn. I can however lift the secondary, just not lower.  But I mainly have to tune it and play around I guess. See, earlier I manage to run it wrong with way too much duty, so it did 18" power arcs at 30vac into the voltage doubler...but I was running the system wrong I guess.  Either way I'll try to tune it and see what happens...will keep posted..

> Date: Thu, 9 Jun 2011 22:31:01 +0100
> From: tesla@xxxxxxxxxxxxxxxxxxxxxxxx
> To: tesla@xxxxxxxxxx
> Subject: Re: [TCML] DRSSTC RF cycles
> 
> Justin,
>      I usually tweak up the cycles until the arc gets no longer into 
> free air.
> At this point putting in more cycles only makes the arc brighter and no 
> longer so I take that point as the most efficient use of energy.
> 
> The other limiting factor is how much current your IGBT's will stand, It 
> may be that you reach the limit of your IGBT's in either current or heat 
> dissipation before you get to the point that your streamers no longer grow.
> 
> Coupling will make a difference as a lower coupling will allow the 
> current to build over more cycles than looser coupling.
> 
> I don't think there is a golden rule and each coil will "like" different 
> coupling & on times.
> 
> Cheers
>          Derek
> 
> On 09/06/2011 18:26, Justin B wrote:
> >
> > Hey all coilers, I have been recently building a large size DRSSTC which operates on a CM300, dual halfbridge model IGBT. In the past, this coil would just make small sparks, and once i hit 60VAC, it went from 1mm spark to 7" power hungry sparks.  I figured that was because it was out of tune.  So, after adding more primary turns, I now have the range of Over and under tuning to match the resonance frequency.
> >
> > But, for a CM300 IGBT driven coil, whats the best way to figure out what RF cycle count to use?  Im afraid doing too much could risk the system, but when googling, I see some do 3-4. some 10, some even as high as 20.  Is there any way to actually KNOW the best range for your coil?  Right now my system is still doing tiny sparks until i reach X voltage.  I have not yet cranked that dial, as I figured a DRSSTC should gradually grow length as you crank it, like a SSTC, shouldn't it?  Or do all DRSSTCs go from tiny to giant sparks?  Right now I have a duty cycle control on the interrupter, and a 15-turn pot on the driver, to limit the duty so I can get exact amount of cycles.
> >
> > Please let me know your thoughts, Thanks!
> > -Justin
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